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Total Knee Replacement

Total knee arthroplasty for end-stage degeneration, including management of PJI, component malalignment, and aseptic loosening.

256 citationsUpdated Sep 2026

For patients: a plain-language version of this topic is available. See the patient guide.

Overview

The primary objective of total knee arthroplasty (TKA) is to deliver the best possible outcome for each individual patient, whether by restoring the native knee or creating an optimal prosthetic joint [2, 3]. For the vast majority of patients, a standard conventional TKA with a familiar surgical approach and standard components leads to satisfactory long-term clinical outcomes [15]. While there is no single 'best' way to perform the procedure [15], TKA is generally considered the last surgical option for unicompartmental osteoarthritis [17]. Indication criteria for TKA are based on limited evidence [21] and should consider the patient’s general health, emotional role, and knee function to predict outcomes [217]. The Appropriate Use Criteria provide guidance for determining the appropriateness of surgical options based on patient-specific factors [35].

Headline outcome data indicate that TKA can be performed safely in specific populations, including nonagenarians and patients with end-stage renal failure, provided careful patient selection excludes those with stroke or peripheral vascular disease [56, 57]. However, nearly 20% of patients remain dissatisfied following well-performed TKA with good functional outcomes, often due to unfulfilled expectations [51]. Most patients are successfully treated, but a certain number remain unhappy, requiring careful analysis of whether symptoms are surgery-related or patient-related [36]. Periprosthetic joint infection is the most common indication for secondary TKA revision within one year after primary TKA [60]. There is a lack of consensus regarding definitions for poor outcome after TKA, highlighting the need for standardized definitions to improve comparability across studies [5].

Unicompartmental knee arthroplasty (UKA) offers clinical results and survivability that are as good as, or better than, TKA with careful attention to specific patient and anatomic indications [8]. Evidence suggests that many originally described contraindications to UKA are no longer applicable in modern practice [19], and expanded indications for younger and heavier patients have been associated with comparable clinical outcomes [22, 179]. Good-to-excellent outcomes can be achieved following UKA and TKA in patients less than 65 years of age [214]. The health benefits of kinematic TKA were maintained after a minimum duration of follow-up of ten years [167]. In salvage TKA, the implant design does not significantly affect the overall functional outcome [53]. Further data must be collected regarding long-term outcomes for revision TKA using kinematic alignment for the restoration of joint line obliquity [43].

Anatomy & Pathophysiology

Bony Anatomy and Alignment

The knee functions as a hinge joint incorporating both gliding and rolling motions essential to its kinematics [85]. During the final 15 degrees of extension, the tibia externally rotates 5 degrees via the "screw-home" mechanism [85]. The mechanical limb line, or Mikulicz line, extends from the femoral head center to the ankle center and normally passes within the confines of the knee [11]. Femoral alignment is defined by two axes: the mechanical axis of the femur (MAF), extending from the femoral head center to the center of the distal femur intercondylar groove, and the anatomic axis of the femur (AAF), defined by the femoral medullary canal [11]. The mechanical lateral distal femoral angle (mLDFA) is subtended by the MAF and the distal femoral intercondylar line, with a neutral value of 90 degrees [11]. In contrast, the anatomic lateral distal femoral angle (aLDFA) is subtended by the AAF and the distal femoral intercondylar line, usually measuring less than 90 degrees [11].

Tibial alignment is defined by the mechanical axis of the tibia (MAT), extending from the ankle center to the center of the proximal tibia [11]. The mechanical proximal tibial angle (mPTA) is subtended by the proximal tibial intercondylar line and the MAT [11]. The native proximal tibia is often in slight varus, with an average mPTA of 3 degrees varus [13]. During total knee arthroplasty, cutting the proximal tibia perpendicular to the mechanical axis can result in a trapezoidal and unbalanced flexion gap if not compensated [13]. This trapezoidal gap causes relative lateral tilt of the patella, leading to either a loose lateral compartment or a tight medial compartment [13]. A rectangular flexion gap is achieved by externally rotating the femoral component to compensate for native tibial varus, thereby optimizing patellar tracking and stability [13].

For mechanical alignment, the distal femoral bone cut is made perpendicular to the MAF to achieve an mLDFA of 90 degrees, while the proximal tibial bone cut is made perpendicular to the MAT to achieve an mPTA of 90 degrees [172]. Kinematic alignment maintains native limb alignment by making the distal femoral cut at the native mLDFA and the proximal tibial cut at the native mPTA [172]. The tibial tubercle–trochlear groove (TT–TG) distance measures lateralization of the tibial tubercle, with normal values between 9 and 13 mm [40]. A TT–TG distance over 20 mm is highly associated with patellar instability [40].

Ligamentous Anatomy and Biomechanics

The anterior cruciate ligament (ACL) comprises two bundles: the anteromedial bundle, which is tight in flexion and primarily resists anterior tibial translation, and the posterolateral bundle, which is tight in extension and primarily resists rotatory loads [85]. The ACL measures approximately 30 mm in length and 11 mm in diameter, with a composition of 90% type I collagen and 10% type III collagen [85]. Its tensile strength is approximately 2200 N, reaching up to 2500 N in young individuals [183]. The posterior cruciate ligament (PCL) resists posterior tibial translation at all degrees of knee flexion and has a tensile strength of approximately 2500 to 3000 N [85, 183].

Collateral and accessory ligaments provide additional stability. The superficial medial collateral ligament (sMCL) has a tensile strength of approximately 550 N, while the deep medial collateral ligament (dMCL) has a tensile strength of approximately 100 N [183]. The sMCL proximal division resists valgus tibial translation and tibial external rotation [85]. The lateral collateral ligament (LCL) has a tensile strength of approximately 750 N and resists varus tibial translation and tibial external rotation, especially at 30 degrees of knee flexion [85, 183]. The posterior oblique ligament (POL) has a tensile strength of approximately 250 N [183]. The popliteus tendon resists tibial external rotation, especially in knee flexion, while the oblique popliteal ligament resists knee hyperextension and varus tibial translation [85].

As the knee flexes, the center of joint rotation moves posteriorly, causing rolling and gliding at the articular surfaces [183]. Ligaments anterior to the flexion axis stretch as the joint flexes, while ligaments posterior to the axis shorten [183].

Meniscal Anatomy and Biomechanics

The menisci transmit 50% to 75% of axial loads across the knee in full extension and 85% of axial loads in 90 degrees of knee flexion [183]. The medial meniscus bears 30% to 40% of the tibiofemoral load, whereas the lateral meniscus bears 70% [183]. Menisci decrease peak contact stresses at the articular surface by 100% to 200% [183]. Resection of 75% of the radial meniscal width results in an increase in peak contact stresses equivalent to that after a segmental or total meniscectomy [183]. The lateral meniscus has twice the excursion of the medial meniscus during knee flexion [183]. In an ACL-deficient knee, the posterior horn of the medial meniscus acts as a major secondary stabilizer against anterior tibial translation [183].

Meniscal root tears completely disrupt the circumferential fibers of the meniscus, leading to meniscal extrusion [183]. Biomechanical studies show similar load patterns in posterior meniscal root tears and complete meniscectomy, rendering them functionally equivalent [183, 199]. The medial meniscus is torn approximately three times more often than the lateral meniscus [199]. Lateral meniscus tears occur more commonly with acute ACL tears, while medial meniscal root tears are associated with chondral injuries [199]. There is an increased rate of osteoarthritis in knees after meniscal tears and meniscectomy, particularly on the lateral side [199].

Patellar Anatomy and Tracking

Internal rotation of the femoral component causes the patellar groove to face inward, adversely affecting patellar tracking and flexion kinematics [13]. This internal rotation results in relative lateral tilt of the patella [13]. To center the patellar groove under the patella and create a balanced flexion gap, the femoral component should be externally rotated [13]. An increased Q angle increases the resultant lateral subluxation force on the patella [13]. The shape of the resurfaced patella is a dome, which is less able to resist lateral pull effects compared to other designs [13].

Patellar instability exists on a spectrum from frank dislocation to subtle subluxation, with dislocation typically occurring laterally [40]. During reduction of the patella, the articular cartilage on the medial facet is most commonly injured [40]. The medial patellofemoral ligament (MPFL) is often disrupted in complete patellar dislocation, most frequently at its patellar insertion [40]. The Schottle point for the femoral attachment of the MPFL occurs 1 mm anterior to the posterior cortex extension line and 2.5 mm distal to the posterior origin of the medial femoral condyle [40]. Trochlear dysplasia can be identified on a lateral radiograph by the presence of a crossing sign or a supratrochlear spur [40]. A crossing sign is present when the trochlear groove line intersects the anterior femoral condyle [40].

Patellar thickness affects patellofemoral kinematics after total knee arthroplasty [132]. Kinematic alignment restores native patellar tracking patterns more closely than mechanical alignment [141]. Kinematically aligned total knee arthroplasty better restores patellar kinematics and patellofemoral contact pressure distribution to the native condition than mechanically aligned total knee arthroplasty during deep knee flexion [133]. None of the analyzed surgical patellar interventions could restore natural patellar kinematics after total knee arthroplasty [161]. Tibial component rotation did not influence patellar kinematics in a cadaveric investigation using a ligament-balanced technique [147].

Pathophysiology of Pain and Instability

Varus thrust indicates ligament stretch-out on the convex side of the thrust, overloading the medial compartment and accelerating cartilage degeneration [38]. Valgus thrust indicates ligament stretch-out on the convex side of the thrust, overloading the lateral compartment and accelerating cartilage degeneration [38]. Referred pain from the hip typically presents in the anterior-medial knee region via the distal branch of the obturator nerve, while referred pain from the spine typically involves L3 and L4 nerve roots [59].

Infection is the number one reason for revision total knee arthroplasty and the number one reason for revision within 2 years of index primary total knee arthroplasty [59]. Aseptic mechanical implant loosening is the number two reason for revision total knee arthroplasty [59]. Early aseptic loosening can result from failure of osteointegration into cementless implants or cement fixation failure, while late aseptic loosening can result from cement fixation failure due to PMMA fatigue or osteolysis with bone resorption from cement [59]. Implant malposition or malalignment typically presents with knee stiffness and activity-related pain [59]. Instability results in abnormal excessive limb subluxation or angulation with weight-bearing stress [59].

Early polyethylene wear debris presentation includes a warm knee and effusion due to reactive synovitis, while late presentation includes osteolysis with bone resorption and retroprosthetic bone resorption [59]. Hypersensitivity to implants typically presents with constant global pain, normal serum biomarkers, and negative aspiration studies [59]. Unbalanced gaps in total knee arthroplasty cause pain from tightness or instability [9]. The flexion gap is controlled by the posterior cut of the femur, the tibial cut, and the posterior cruciate ligament, while the extension gap is controlled by the distal cut of the femur, the tibial cut, and the posterior capsule [9]. Posterior capsule recession is performed with the knee flexed at least 90 degrees because the popliteal artery relaxes posteriorly in flexion [9]. A symmetrical gap problem is addressed by tinkering with the tibia first, while an asymmetrical gap problem is addressed by tinkering with the femur first [9]. Cutting 2 mm of proximal tibia corrects a 10-degree contracture, as does cutting 2 mm of distal femur [9].

Pathophysiology of Wear and Osteolysis

Macroscopic polyethylene failure generally occurs in the intermediate lifecycle of the implant [69]. If untreated, areas of broken polyethylene allow metal-to-metal contact, creating metallosis [69]. To keep knee bearing contact stress below the yield strength of UHMWPE (12–20 MPa), the polyethylene must be at least 6 to 8 mm thick for traditional non-highly cross-linked material [69]. Many second-generation knee systems had polyethylene inserts with a thickness of 4 to 5 mm in the thinnest region, whereas current designs ensure that polyethylene thickness in the thinnest areas of the insert is at least 6 mm [69]. Flat polyethylene designs should be avoided because knee loads exceed the yield strength of UHMWPE due to a thin line of joint contact [69]. Goals of current tibial articular designs are to maximize contact area and minimize contact loads [69]. Sliding movements are least pronounced in a posterior-stabilized or anterior-stabilized knee design with a congruent polyethylene insert, as sliding wear across the tibia in laboratory testing created surface and subsurface cracking with high wear [69].

Osteolysis occurs late in the lifecycle of the implant, typically at 13 to 15 years [205]. It is initiated by submicron shedding of microparticulate polyethylene debris that invades bone surrounding the knee [205]. Macrophages are stimulated by phagocytosis of submicron-sized polyethylene wear particles and release TNFα, IL-1β, and IL-6 [205]. Subsequent up-regulation of RANKL production by osteophytes leads to RANK binding on osteoclast progenitors, mediating osteoclast differentiation and increased bone resorption [205]. The most common site for osteolytic lesions in total knee arthroplasty is behind the posterior femur [205]. Femoral osteolysis can be more difficult to detect on an AP radiograph because lesions are typically located in the posterior condyles and obscured by the femoral implant, whereas tibial osteolytic lesions are usually more readily visible on radiographs than femoral lesions [202]. Smaller wear particles less than 10 mm are more readily absorbed by macrophages, which release cytokines that signal osteoclasts to resorb bone [202]. PMMA cement debris can contribute to osteolysis when caused by motion between the implant and cement due to loosening or debonding [202]. Limb malalignment causes asymmetric loading of the knee, which can result in early loosening, with loosening appearing to occur more frequently with varus malalignment than with valgus malalignment [202].

Pathophysiology of Instability and Constraint

Soft tissues about the knee may not support an unconstrained prosthesis due to the loss of key vital support structures [55]. A constrained nonhinged total knee arthroplasty uses a high central post that substitutes for medial and lateral collateral ligament function, whereas a standard posterior-stabilized post is not considered a constrained bearing [55]. Residual flexion gap laxity due to soft tissue weakness is the most common indication for a constrained nonhinged total knee arthroplasty [55]. A rotating hinge total knee arthroplasty links femoral and tibial components with a connecting bar and bearings, preventing hyperextension [55]. Global instability due to trauma, infection, or multirevised knee is the number one indication for a rotating hinge total knee arthroplasty, and hyperextension instability is an absolute indication [55]. The functional Achilles heel of a rotating hinge design is buckling, as it changes sagittal knee kinematics from polyaxial to uniaxial [55].

Loss of collateral ligament support requires an implant constrained to varus and valgus stress [202]. Flexion instability can result from the sacrifice of the anterior cruciate ligament in both cruciate-retaining and posterior-stabilized total knee arthroplasties [202]. Radiographs of patients with symptomatic flexion instability typically demonstrate paradoxical motion, or anterior subluxation of the femur on the tibia in flexion [202].

Pathophysiology of Extensor Mechanism Failure

Extensor mechanism dysfunction is the most frequent complication and the most commonly cited reason for secondary surgery after total knee arthroplasty [72]. The incidence of extensor mechanism complications has decreased from approximately 12% to 1.5% over the past three decades [72]. Patellofemoral instability is the most commonly reported extensor mechanism complication [273]. Patellar fracture or rupture of the quadriceps or patellar tendon can cause catastrophic disruption of the extensor mechanism [273]. The incidence of extensor mechanism disruption after total knee arthroplasty has been reported to range from 0.17% to 2.5% [323]. Risk factors for extensor mechanism disruption include patient comorbidities, prior knee procedures, surgical technique, and prosthetic design [323]. Over-resection of patellar bone is a cause of patellar fracture, with a minimum thickness of 13 mm required [200]. Compromised circulation from an extended lateral retinacular release can result in osteonecrosis with fracture and fragmentation of the patella [200]. Patellofemoral maltracking can cause bone overload.

Classification

Outcome and Satisfaction Scoring

WOMAC: The Western Ontario and McMaster Universities Osteoarthritis Index score reliably classifies patient satisfaction after total knee arthroplasty into post-operative categories of excellent, good, fair, and poor for both component and total scores [164].

Knee Society Scoring System: This system categorizes patients into Category A (unilateral replacement, or bilateral replacement with a successful contralateral arthroplasty), Category B (unilateral replacement and a symptomatic contralateral knee), and Category C (multiple joints involved by arthritis, or a medical infirmity) [42]. In studies of posterior stabilized prostheses, overall knee scores averaged 94 points for Category A, 92 points for Category B, and 89 points for Category C [42]. Functional scores averaged 85 points for Category A, 64 points for Category B, and 47 points for Category C [42].

Hospital for Special Surgery Rating Scale: This scale classifies results as excellent, good, fair, or poor and was utilized in studies of posterior stabilized prostheses [42].

Statistical Model-Based Approaches: Classifications of good versus poor outcome should not rely on arbitrary cutoff scores, as such homogeneity impedes scientific progress [182]. Instead, non-biased statistical model-based approaches are proposed for classifying outcomes following knee arthroplasty [182]. An inventory review highlights the lack of consensus and the wide variety of definitions for poor outcome, emphasizing the need for standardized definitions to improve comparability across studies [5].

Radiographic and Anatomical Classification

Knee Society Radiographic Evaluation and Scoring System: This system provides a classification framework for total knee arthroplasty radiographs [39].

Periprosthetic Femur Fracture Classification: A new classification system for periprosthetic femur fractures following total knee arthroplasty considers fracture location and implant type [150]. This system is easy to use, demonstrates good interobserver reliability, and allows conclusions to be drawn on treatment recommendations [150].

Unified Classification System: This system proposes a rational approach to treatment regardless of the bone broken or joint involved, aiming to improve understanding and consistency in reporting periprosthetic fractures [224].

Anderson Orthopaedic Research Institute: This classification is used to classify preoperative tibial and femoral bone loss in revision total knee arthroplasty [307].

Ahlback Classification: This system grades the presence of osteoarthritic changes in the nonreplaced compartment in unicompartmental knee replacement [321].

Modified Joint Line Obliquity Classification: This classification assesses postoperative joint line obliquity, which was associated with high survival rates following total knee arthroplasty at a mean follow-up of 12.7 years [206].

Brooker Classification: This four-stage system for hip heterotopic ossification has been implemented widely and is the only validated grading system for hip heterotopic ossification [316]. Maloney et al. modified this classification to reflect functional limitation resulting from heterotopic ossification by subdividing classes III and IV into A and B [316]. The absence of a single, standardized classification system for heterotopic ossification precludes the comparisons of heterotopic ossification severity between studies [54].

Anatomical Categorisation: The anatomical site of radiographic degeneration is an independent variable influencing the outcome of total knee arthroplasty [220]. Precise anatomical categorisation of knee osteoarthritis is supported for use in outcome studies with the adoption of patient-reported outcome measures by arthroplasty registries [220].

Surgical Indication and Appropriateness

Appropriateness Criteria: Validated total knee replacement appropriateness criteria include 16 mutually exclusive combinations of 5 elements: age, symptomatology, radiographic knee osteoarthritis severity, number of knee compartments involved, and knee stability [25]. Patients are classified into three categories based on these criteria: appropriate, inconclusive, and inappropriate [25]. Individuals classified as "appropriate" and "inconclusive" are combined into a group defined as "potentially appropriate" for total knee replacement because they have been shown to have the same 2-year postoperative trajectories of pain and functional improvement [25]. The "inappropriate" group is defined as "likely inappropriate" for total knee replacement [25]. A procedure is considered appropriate if its expected benefit exceeds its expected negative consequences by a sufficiently wide margin [25].

Revision and Complexity Classification

Revision Knee Complexity Classification (RKCC): This classification serves as a guide for surgeons to support regional clinical networking in revision knee surgery [41].

Baldini Classification: A modified grading system for the Baldini Classification for Revision Total Knee Arthroplasty was developed and validated to improve reliability [216].

ICD Coding: International Classification of Diseases, Ninth Revision, Clinical Modification procedure codes are used to identify patients undergoing revision total knee arthroplasty [301]. International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes are used to identify the indication for each revision procedure [301]. The transition to International Classification of Diseases, Tenth Revision coding in the fourth quarter of 2015 introduces uncertainty into data sets and has the potential to confound results regarding revision arthroplasty indications [301].

Diagnosis-Related Groups: Several countries' Diagnosis-Related Group systems might be improved through the introduction of classification variables for revision of knee replacement or for the presence of complications or comorbidities [124].

Implant Classification: A generic implant classification enables comparison across implant designs, with a complete implant library containing characteristics of 32,500 orthopaedic implants covering about 85 different hip and 85 different knee implants [242].

Phenotype and Morphometry

Functional Knee Phenotypes: These phenotypes go beyond utilizing implants manufactured based on individual 3D-data and may help to structure and categorize individual morphology and alignment to identify the optimal total knee arthroplasty strategy [215]. The distribution of functional phenotypes of the knee in patients undergoing total knee arthroplasty is different from those found in a reference non-osteoarthritic population [46]. Advancements in total knee arthroplasty require a multifaceted approach that recognizes variations in knee morphometry and phenotypes, as not all knees are the same [4].

Ethnic Morphometry: Absolute and relative differences in knee dimensions exist between Asian and Caucasian knees, and not all total knee arthroplasty systems fit these phenotypes well [196].

Intraoperative and Complication Classification

Component Loosening: A Delphi study established a consensus among knee revision surgeons on the definition of intraoperatively determined component loosening as visible fluid motion on manipulation [234].

Fractures: Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries [225].

Hinged Prostheses: The incidence of major complications is much higher with hinged total knee arthroplasty than with other types of total knee arthroplasty and arthrodesis [237].

Clinical Presentation

Assessment of Painful Total Knee Arthroplasty

A complete and accurate history, physical examination, and radiographic assessment are critical for determining a specific diagnosis and treatment plan for pain after total knee replacement [23]. The workup should include evaluation for infection, neurogenic pain, referred pain from the hip or back, and mechanical sources of pain [281]. This evaluation requires a thorough history and physical examination, laboratory studies, and plain radiographs, with additional nuclear medicine studies or specialized imaging as necessary [281]. A practical 10-step diagnostic algorithm for failure analysis includes an extended history, analysis of the type of pain, psychological exploration, thorough clinical examination including spine, hip and ankle, laboratory tests, joint aspiration and test infiltration, radiographic analysis and special imaging techniques [137]. It is important to enquire about the length and type of conservative therapy when evaluating a painful total knee arthroplasty [137].

History and Pain Characterization: A history of pain that develops immediately after surgery and persists without a pain-free interval, along with pain at rest and with weight bearing, suggests an inflammatory and/or neurogenic source of pain [281]. Pain during weight-bearing activity or knee motion is consistent with a mechanical source of pain [281]. Pain associated with localized warmth and swelling that occurs more after activity and is relieved with rest is less consistent with infection and more typical of soft-tissue inflammation resulting from postsurgical rehabilitation [281]. Pain described as burning or numbness that is nonfocal on examination or improves with analgesic medications, neuropathic pain medications, local trigger point injections, or epidural injections supports the diagnosis of neurogenic pain [281]. A history of pain and effusion that occurs after activity and is relieved with rest is consistent with flexion instability [281]. Pain that develops late after total knee arthroplasty is more often associated with loosening or ultra-high-molecular-weight polyethylene wear, although late hematogenous infection should be included in the differential diagnosis [281].

Infection Workup: Infection is a common source of pain after total knee arthroplasty and must be ruled out first in all patients [281]. Infection is usually associated with an elevated erythrocyte sedimentation rate and C-reactive protein level and can be detected by aspiration with cell count, differential, and culture [281]. False-negative and false-positive results can occur in the laboratory evaluation for infection, and additional imaging studies may be necessary [281]. A history and physical remain the most important diagnostic tools for periprosthetic joint infection [134]. Many current laboratory tests for periprosthetic joint infection are indirect measures of infection, lack specificity for diagnosis, but serve as sensitive and cost-effective screening tools [134]. Biomarkers hold the promise of improved specificity and are becoming increasingly popular as a diagnostic tool for periprosthetic joint infection [134]. Periprosthetic joint infection is the leading cause of revision for failed total knee arthroplasty, accounting for 16.8% of all knee revisions [134]. Joint aspiration was encouraged as a primary diagnostic procedure but not always performed in a retrospective analysis of periprosthetic joint infection diagnosis [140]. Ordering X-ray examination and routine inflammatory markers (leukocyte count in peripheral blood and plasma C-reactive protein) were standardized laboratory-confirmed steps in a pragmatic evaluation for suspected periprosthetic joint infection [140].

Physical Examination and Referred Pain: Motor strength, sensory, and vascular examination of the lower extremity complete the assessment of a painful total knee arthroplasty [1]. Gait analysis and dedicated examinations of the ipsilateral hip and spine are performed because radiating or referred pain may be experienced in the anterior thigh or knee [1]. Crepitus and patellar clunk syndrome may be carefully assessed during the physical examination of a painful total knee arthroplasty [1]. MRI utility in working up a painful arthroplasty is demonstrated when history, physical examination, and other diagnostic utilities fail to provide answers [34]. The role for MRI in the postarthroplasty knee has yet to be clearly defined [34].

Mechanical Causes: Patellar Problems: Mechanical causes of early pain after total knee arthroplasty include patellar maltracking, patellar clunk or crepitus, tibiofemoral instability, periprosthetic fracture, or occult implant loosening [281]. Patellar problems are usually evident on physical examination because the location of pain is restricted to the patellofemoral joint [281]. Patients with patellar problems may present with reduced knee range of motion and flexion [281]. Patellar clunk is a complication of posterior-stabilized total knee arthroplasty that occurs when a fibrous nodule at the inferior pole of the patella catches in the trochlear groove during knee extension [281]. Patellar clunk was a problem with older implant designs but is rarely described with newer ones [281]. Patellar crepitus is more common with current posterior-stabilized designs and may cause anterior knee pain [281]. Symptoms of patellar clunk and crepitus are relieved by open or arthroscopic excision of the fibrous nodules and synovium [281]. Patellar maltracking and subluxation may result from dehiscence of the medial retinacular arthrotomy, femoral or tibial component internal rotation, or patellar component malpositioning [281]. Rotational orientation of the femoral implant may be assessed on an axial view of the patella but is better quantitated using CT with metal artifact reduction [281]. Symptomatic patellar subluxation or maltracking resulting from internal rotation of the femoral or tibial components requires revision of the malaligned components [281].

Mechanical Causes: Instability and Loosening: Flexion instability caused by intact but attenuated soft-tissue constraints can be detected on physical examination by varus and valgus stress testing [281]. Laxity in flexion instability is typically more evident in flexion than in full extension as the posterior capsule and hamstrings contribute to stability in extension [281]. Flexion instability is more common with cruciate-retaining total knee arthroplasties than with posterior-stabilized total knee arthroplasties [281]. Flexion instability is associated with paradoxic motion or rolling forward of the femoral implant, which can be seen on flexion lateral radiographs as anterior subluxation of the distal femur on the tibia [281]. Complete dislocation of a posterior-stabilized knee presents with gross instability in flexion on physical examination and posterior displacement of the tibia on the femur [281]. Complete dislocation of a posterior-stabilized knee is more common when excessive posterior slope occurs with the tibial cut and with some posterior-stabilized-designed total knee arthroplasties [281]. Wear can be seen radiographically as asymmetric height of the tibial plateaus, although rotation and flexion of the knee can alter the projected height of the joint space, making radiographic measurements of wear inaccurate [281]. Loosening occurs when subsidence or displacement of the component or a complete or progressive radiolucency at the implant and bone interface occurs [281]. Amongst specialized knee revision surgeons, there is high variability in clinical and radiological criteria that are seen as important contributing factors to diagnosis of knee implant loosening [30]. Weight-bearing pain and implant migration, progressive radiolucencies, radiolucency more than 2 mm and subsidence on radiographs and CT are generally accepted criteria for knee arthroplasty loosening [30].

Preoperative Evaluation and Indications

Preoperative evaluation of a patient requiring revision total knee arthroplasty involves obtaining a thorough history and performing a clinical examination in addition to laboratory assessment and a critical review of radiographs [126]. The goals of the history in revision total knee arthroplasty are to determine if the patient’s symptomatology is consistent with a failed total knee arthroplasty and to rule out conditions in which revision may be contraindicated such as infection, Charcot arthropathy, neuromuscular disease, or adverse medical conditions [126]. Analysis of previous surgical procedures, including review of previous operative reports, is necessary to assess the previous surgical approach used, the soft-tissue releases performed, and the size and type of the present prosthetic components [126]. Clinical examination for revision total knee arthroplasty includes assessment of range of motion, ligamentous stability, lower-limb alignment, and patellofemoral tracking [126]. The skin is carefully inspected during revision total knee arthroplasty evaluation to determine previous skin incisions, mobility of the anterior soft tissues, and presence of any preexisting ulcerations that would require treatment before proceeding [126]. A neurologic examination is performed during revision total knee arthroplasty evaluation to ensure the patient has adequate motor control of the operative lower extremity [126]. If diminished pulses are present during revision total knee arthroplasty evaluation, noninvasive arterial studies are obtained and a preoperative vascular surgery consultation is considered [126]. Signs of venous insufficiency are evaluated with duplex color ultrasonography during revision total knee arthroplasty evaluation [126]. The examination for revision total knee arthroplasty must confirm that the patient’s symptoms are truly secondary to a failed total knee arthroplasty by ruling out referred pain from adjacent areas, such as a diseased hip joint, or radicular pain from spinal nerve root impingement [126].

Indications and Patient Selection: The AAOS Appropriate Use Criteria for Surgical Management of Osteoarthritis of the Knee categorize treatments as Appropriate, May Be Appropriate, or Rarely Appropriate based on specific clinical scenarios to assist in decision-making [174]. The AAOS Appropriate Use Criteria were developed by a voting panel reviewing 864 scenarios [174]. Patients were classified into 3 categories based on appropriateness criteria: appropriate, inconclusive, and inappropriate [25]. Individuals classified as “appropriate” and “inconclusive” were combined into 1 group defined as “potentially appropriate” for total knee replacement because they have been shown to have the same 2-year postoperative trajectories of pain and functional improvement [25]. Pain symptoms of moderate or severe pain are unequivocal when considering a total knee arthroplasty [166]. Total knee replacement cannot be seen as an isolated intervention without considering the many other factors that contribute to outcomes [26]. The optimal surgical treatment of knee osteoarthritis in the young and active patient is still insufficiently defined, requiring a compromise between pain relief, functional restoration, and treatment durability [48]. Total knee arthroplasty done in young and presumed active patients less than 65 years have excellent survivorship [6]. Good early outcomes, as measured by the Oxford Knee Score and EQ-5D, can be anticipated following knee replacement regardless of the patient's age, although younger patients gain greater improvement [44]. Patients aged 68 years or older experience deterioration in functional outcomes and quality of life from 2 to 10 years after total knee arthroplasty [176]. The estimated lifetime risk of revision knee arthroplasty varied depending on patient sex, age, and underlying diagnosis [171]. Presence of diagnosis codes for both knee osteoarthritis and obesity are risk factors for knee arthroplasty following knee arthroscopy in patients 50 years and older [123]. With careful patient selection, bilateral knee replacement under a single anaesthetic would be a suitable option for patients who present with bilateral symptomatic arthritis of the knee [165]. More than half the patients presenting for total knee arthroplasty had mild-to-severe contralateral knee pain, most of whom had a clinically meaningful improvement but were significantly less likely to be satisfied with their total knee arthroplasty [145]. Surgical timing preferences for knee replacement vary between patients older than 65 years (immediate surgery only when pain is intense) and younger patients (immediate surgery no matter the amount of pain) [178]. Clinically, elderly patients undergoing hip or knee replacement surgery should perform well in terms of preoperative and perioperative management [168]. Routine pathological examination of surgical specimens from patients undergoing primary total hip or knee replacement because of the clinical diagnosis of osteoarthritis had limited cost-effectiveness due to the low prevalence of findings that altered patient management [170].

Expectations and Guidelines: The goal of total knee arthroplasty remains delivering the best possible outcome for each individual patient, whether through restoring the native knee or creating the optimal prosthetic knee [3]. Patients from different countries have different expectations regarding total knee arthroplasty, which are not fully explained by differences in sociodemographic factors, clinical characteristics, and pain and functional status [160]. The KSPQ is a valid questionnaire to assess patients' expected and desired outcomes of knee replacement surgery and their perception of their current abilities and function, and discrepancy between these [157]. The findings from a prospective randomized clinical trial provide insights into the function of different knee arthroplasty designs during deep kneeling and may allow improved management of patients' functional expectations [37]. The guideline provides 16 recommendations and seven options based on a systematic review of over 1,500 full-text articles to assist surgeons in the surgical management of osteoarthritis of the knee [27]. The panel reached consensus on 18 critical clinical questions spanning general principles, total hip arthroplasty, and total knee arthroplasty [45].

Postoperative Outcomes and Complications

Almost a third of the patients continued to have residual knee pain at 2 years post-total knee arthroplasty [143]. Factors such as gender, presence of ischaemic heart disease, and implant type are significantly associated with the development of residual knee pain and/or poorer functional outcome scores after total knee arthroplasty [143]. A small but clinically significant minority of people continued to have high pain levels at 3-, 12- and 36-months following a primary total knee replacement for osteoarthritis [47]. Improvement in knee pain after total knee arthroplasty is associated with a reduction in pain in other bodily regions, suggesting a potential physiological link, though persistent pain remains common and improvement does not equate to cure [159]. Long-term patient-reported outcome measures for total knee and hip arthroplasty beyond one or two years are often incomplete and lose sensitivity [49]. ED visits following elective major joint replacement were numerous and most commonly for pain-related diagnoses [175]. This inventory review identifies a wide variety of definitions for poor outcome after total knee arthroplasty, highlighting the lack of consensus and the need for standardized definitions to improve comparability across studies [5].

Revision and Management: Revision total knee arthroplasty is a challenging procedure requiring a correct diagnosis of the original cause of failure and a detailed plan [32]. The authors acknowledge that revision of well-fixed mechanically-aligned total knee arthroplasty using kinematic alignment for the restoration of joint line obliquity is not a universally accepted indication for revision total knee surgery and that further data must be collected regarding long-term outcomes [43]. The use of knee arthroplasty should be thoroughly monitored with more emphasis on standardization in the decision-making process and preventive measures [28]. The unstable total knee arthroplasty may result from a variety of distinct etiologies which must be identified and treated at the time of revision [177].

Investigations

Clinical Assessment and History

Revision total knee arthroplasty requires a correct diagnosis of the original cause of failure and a detailed plan [32]. Assessment of a painful total knee arthroplasty includes evaluating crepitus, patellar clunk syndrome, motor strength, sensory and vascular examination of the lower extremity, gait analysis, and dedicated examinations of the ipsilateral hip and spine [1]. Radiating or referred pain from the hip or spine may be experienced in the anterior thigh or knee [1].

Differentiating pain onset narrows the differential diagnosis. Immediate-onset pain is associated with acute postoperative infection, periprosthetic fracture, severe implant malpositioning, polyethylene liner dislocation, venous thromboembolism, and ligamentous injury [1]. Delayed-onset pain is associated with hematogenous or chronic infection, implant malpositioning or loosening, knee instability, extensor mechanism disorders, arthrofibrosis, and rare causes [1]. Pain that differs from the preoperative presentation is associated with infection, implant malpositioning or loosening, knee instability, extensor mechanism disorders, arthrofibrosis, and rare causes [1]. Pain that matches the preoperative presentation is associated with hip pathology, spine pathology, vascular pathology, tendinitis and bursitis, minimal preoperative knee osteoarthritis, and rare causes [1].

Plain Radiography

Weight-bearing AP and lateral views are standard for initial evaluation of the knee [38]. Standard radiographic evaluation also includes a weight-bearing knee flexed at 45-degree angle imaged posterior to anterior, the sunrise view (Merchant view), and extension and flexion lateral views [38]. A standing full-length AP radiograph from hip joint to ankle joint evaluates limb alignment and knee deformity and identifies femoral and/or tibial bone deformity [38]. Utilization of an axial weight-bearing view to evaluate total knee arthroplasty may provide additional information over standard radiographic views [363].

The Kellgren-Lawrence (KL) rating grades the extent of osteoarthritis based on review of the AP knee radiograph [38]. Primary features used for KL rating include osteophytes, joint space narrowing, subchondral sclerosis with or without subchondral cysts, and altered shape of periarticular bones [38]. KL Grade 0 indicates normal knee features with no osteoarthritis [38]. KL Grade 1 indicates osteoarthritis possibly present [38]. KL Grade 2 indicates minimal severity osteoarthritis [38]. KL Grade 3 indicates moderate severity osteoarthritis [38]. KL Grade 4 indicates severe osteoarthritis [38]. Knee arthroplasty is recommended when KL Grade 4 findings are present [38].

Routine radiographic surveillance did not detect any true abnormalities during the first year after primary total joint arthroplasty [327]. Weight-bearing pain, implant migration, progressive radiolucencies, radiolucency more than 2 mm, and subsidence on radiographs and CT are generally accepted criteria for knee arthroplasty loosening [30]. Novel radiographic findings of anterior heterotopic bone formation and cysts develop in patients who have aseptic loosening following primary total knee arthroplasty [369]. Simultaneous biplane radiography can accurately assess the motion of total joint replacements in vivo and may detect early changes before clinical or radiographic evidence of loosening is apparent [364]. A deep learning algorithm using plain radiographs differentiated between 9 unique knee arthroplasty implants from four manufacturers with near-perfect accuracy [333].

Radiographic findings including joint space narrowing are significantly associated with the long term risk of TKA in persons with knee osteoarthritis [296]. Baseline radiographic severity grade was only associated with future total knee arthroplasty risk in the absence of a full-thickness defect [249]. Patients with mild radiographic osteoarthritis are anticipated to gain less from total knee arthroplasty compared to those with severe osteoarthritis [278]. Severe arthritis predicts greater improvements in function following total knee arthroplasty [330]. Radiographic severity of arthritic changes can predict knee-specific functional improvement, but the extent of global functional improvement cannot be predicted by radiographic severity [330]. A low radiological severity of osteoarthritis was not associated with pain 12 months postoperatively [339]. Mild radiographic knee OA was the main predicting factor for dissatisfaction after TKA in patients aged 65 years or less [377]. In a patient who has an unsatisfactory response to their first knee replacement, the best predictor of achieving a satisfactory response to their contralateral knee replacement is the level of radiographic osteoarthritis in that knee [376]. Patients undergoing TKR exhibited significantly worse baseline clinical outcomes, particularly in WOMAC scores, despite having similar radiographic severity to those receiving conservative treatment [392]. Functional and symptomatic measures may be more valuable than radiographic findings in determining surgical intervention for knee osteoarthritis [392]. Standardised radiological imaging should be part of the pre-operative assessment for the Femoro-Patella Vialla joint replacement, especially for the non-dysplastic knee [291].

MRI

MRI is not indicated if the joint space is significantly narrowed on radiograph [38]. MRI is used when osteonecrosis is suspected in the arthritic patient population [38]. Routine screening for osteonecrosis is not necessary, but patients with persistent hip or knee pain should be assessed with MRI [314]. MRI has a noteworthy value of distinguishing suspected periprosthetic joint infection in patients with total knee arthroplasty, but the definition of specific MRI features related to PJIs diagnosis lacks consensus and standardization [292]. Although the role for MRI in the postarthroplasty knee has yet to be clearly defined, its utility in working up a painful arthroplasty when history, physical examination, and other diagnostic utilities fail to provide answers is clearly demonstrated [34].

MRI detected bone marrow lesions, synovitis, and effusion were all significantly associated with the long term risk of TKA in persons with knee osteoarthritis [296]. A thorough preoperative investigation, especially MRI, is required to determine the role of each layer to make the correct decision between fusion, preservation, removal, or resurfacing of the patella in double-layered patella management [324]. Assessment of medial cartilage thickness loss using MRI provides additional utility over standard radiographs in preoperative assessments of medial UKA patients [374]. MRI should be the imaging modality of choice when performing TKA surgery with patient-specific instruments to prevent malalignment [382].

CT

Three-dimensional CT with remodeling is used for preoperative planning for reconstruction associated with dysplasia, post-trauma planning, and complex total knee arthroplasty planning [38].

Bone Scan

MRI and SPECT/CT are currently the most accurate modalities available to aid the diagnosis of aseptic loosening of knee arthroplasty components, based on low certainty of evidence [246]. The diagnostic benefits of SPECT/CT in patients with pain after primary TKA have been proven, with excellent sensitivity and specificity for detection of tibial or femoral component loosening and patellofemoral OA surgically confirmed [343]. SPECT/CT was very helpful in establishing the diagnosis and guiding subsequent management in patients with painful knees after TKA, particularly in patients with patellofemoral problems and malpositioned or loose TKA [341]. The diagnostic benefits of SPECT/CT in patients after total knee arthroplasty have been proven [303]. A standardized algorithm for evaluating patients with painful total knee arthroplasty using combined SPECT/CT is both reliable and useful in management [397].

Tomosynthesis

Tomosynthesis is superior to fluoroscopically guided plain radiography, CT, and MRI for the early detection of small periprosthetic bone defects after total knee arthroplasty in terms of sensitivity, specificity, radiation dose, and cost [326].

Other Considerations

Navigated knee replacement provides few advantages over conventional surgery on the basis of radiographic end points [24]. The use of routinely available preoperative radiology reports provides promising potential to help screen suitable candidates for THA, but not for TKA [286]. In the setting of image-based robotic-assisted TKA performed with functional knee positioning, the rotational alignment of the femoral component changes significantly among different knee phenotypes [328]. Improving long-term outcomes after total knee arthroplasty requires moving beyond the static concept of 'correct alignment option' to integrate static images with dynamic and kinetic insights [385]. Advancements in total knee arthroplasty require a multifaceted approach that recognizes variations in knee morphometry and phenotypes [4].

Treatment

Non-Operative

A stepwise approach with graduated interventional treatment is recommended as pain and functional disability progress in knee osteoarthritis [11]. Patient education programs, self-management programs, and exercise—including supervised, unsupervised, and aquatic modalities—are strongly recommended [11]. Topical NSAIDs, oral NSAIDs, and oral acetaminophen are also strongly recommended for management [11]. Canes, brace treatment, neuromuscular training combined with traditional exercise, sustained weight loss, and intraarticular corticosteroids for short-term relief are moderately recommended [11]. Arthroscopic partial meniscectomy for meniscal tears in patients with concomitant mild to moderate osteoarthritis is moderately recommended [11]. Oral narcotics, including Tramadol, lateral wedge insoles, hyaluronic acid intraarticular injections, and arthroscopy with lavage and/or débridement are not recommended [11]. Supplements such as turmeric, ginger extract, glucosamine, chondroitin, and vitamin D may be helpful [11]. Manual therapy, massage, FDA-approved laser treatment, acupuncture, transcutaneous electrical nerve stimulation, percutaneous electrical nerve stimulation, electromagnetic field therapy, extracorporeal shockwave therapy, platelet-rich plasma, and denervation therapy may improve pain or function [11]. High tibial osteotomy in properly indicated patients with unicompartmental knee osteoarthritis may improve pain or function [11]. Dry needling has unclear utility and efficacy [11]. Free-floating interpositional devices, such as unispacers, are not recommended [11]. Non-arthroplasty therapies accounted for about one third of the costs in treating knee osteoarthritis, with hyaluronic acid comprising only a small fraction (3%) of overall costs [260]. If patients present with negative predictor factors, arthroscopic meniscectomy should not be proposed as second-line treatment, and nonoperative management should be continued until total knee replacement is unavoidable [212].

Operative

Indications: The primary indication for total knee arthroplasty is to relieve pain caused by severe arthritis, with or without significant deformity [50]. Radiographic findings must correlate with a clear clinical impression of knee arthritis before surgery is considered [50]. Conservative treatment measures, including physical therapy, antiinflammatory medications, intraarticular injections, activity modifications, and the use of a cane, should be exhausted before surgery is considered [50]. Patients who do not have complete cartilage space loss before surgery tend to be less satisfied with their clinical result after total knee arthroplasty [50]. Total knee arthroplasty is generally indicated in older patients with more sedentary lifestyles due to the finite expected survival of the implant being adversely affected by activity level [50]. It is clearly indicated in younger patients who have significant functional impairment from osteoarthritis, systemic arthritis, or osteonecrosis with subchondral collapse of a femoral condyle [50]. Severe pain from chondrocalcinosis and pseudogout in an elderly patient is an occasional indication for arthroplasty in the absence of complete cartilage space loss [50]. Severe patellofemoral arthritis in an elderly patient may justify total knee arthroplasty because the expected outcome is better than that of patellectomy or patellofemoral replacement [50]. Deformity can become the principal indication for arthroplasty when progression threatens the expected outcome, such as a flexion contracture progressing beyond 20 degrees [50]. Severe varus or valgus laxity may necessitate a constrained condylar prosthesis to prevent subsequent coronal plane instability [50]. Intervening before severe laxity is present allows the use of a prosthesis that lacks coronal plane constraint and has a more favorable expected survivorship [50]. Total knee arthroplasty should be considered as the last surgical option for unicompartmental osteoarthritis [17]. Total knee arthroplasty among nonagenarians can be performed with a perioperative morbidity and mortality that is acceptable to both patient and surgeon [56]. Nonagenarians undergoing primary total knee arthroplasty had low mortality rates at 90 days (0%) and 1 year (2%) with substantial functional improvements [268]. When total knee arthroplasty is used for appropriate indications, high body mass index should not be considered as a contraindication [104]. Obese patients have less improvement in outcomes with total knee arthroplasty [12]. Total knee replacement plus a 12-week nonsurgical treatment program was more effective than nonsurgical treatment alone for knee osteoarthritis but was associated with more serious adverse events [204].

Contraindications: Absolute contraindications to total knee arthroplasty include recent or current knee sepsis, a remote source of ongoing infection, extensor mechanism discontinuity or severe dysfunction, recurvatum deformity secondary to neuromuscular weakness, and the presence of a painless, well-functioning knee arthrodesis [50]. Relative contraindications include medical conditions that compromise the patient’s ability to withstand anesthesia, immunodeficiency, and the significant rehabilitation necessary to ensure a favorable functional outcome [50]. A severely osteoarthritic ipsilateral hip joint should be considered for arthroplasty before the symptomatic osteoarthritic knee because rehabilitation is easier with a total hip arthroplasty and an osteoarthritic knee than with a total knee arthroplasty and an osteoarthritic hip joint [50]. Other relative contraindications include significant atherosclerotic disease of the operative leg, skin conditions such as psoriasis within the operative field, venous stasis disease with recurrent cellulitis, neuropathic arthropathy, superobesity (BMI ≥ 45), recurrent urinary tract infections, and a history of infections in the proximity of the knee [50].

Preoperative Optimization: Patient optimization is key to ensuring the best chance of a good long-term outcome in total knee arthroplasty [50]. Modifiable risk factors to consider before elective total knee arthroplasty include low vitamin D levels, metabolic syndrome, low albumin, neutropenia, superobesity, and a BMI less than 20 [50]. Delaying primary total knee arthroplasty for up to 8 months while a patient works to improve a modifiable risk factor does not appear to worsen the outcome [50]. The American Academy of Orthopaedic Surgeons Clinical Practice Guideline provides 16 recommendations and seven options based on a systematic review of over 1,500 full-text articles to assist surgeons in the surgical management of osteoarthritis of the knee [27]. In the assessment of a painful total knee arthroplasty, gait analysis and dedicated examinations of the ipsilateral hip and spine are performed because radiating or referred pain may be experienced in the anterior thigh or knee [1]. Crepitus and patellar clunk syndrome may also be carefully assessed during the evaluation of a painful total knee arthroplasty [1].

Surgical Approach / Technique: For the vast majority of patients, a standard conventional total knee arthroplasty with a familiar surgical approach and standard components leads to satisfactory long-term clinical outcomes, and there is no single 'best' way to perform the procedure [15]. For the vast majority of patients, a standard conventional total knee arthroplasty with a surgical approach familiar to the surgeon using standard well-established components, with or without tourniquet, without surgical drain leads to satisfactory long-term clinical outcomes [116]. Conventional surgical technique allows a precise joint line reconstruction in primary total knee arthroplasty [114]. The present meta-analysis encourages the use of minimally invasive techniques for total knee arthroplasty [16]. There are relatively few prospective, randomized studies comparing minimally invasive and conventional exposures for knee arthroplasty, and those that exist fail to substantiate any significant clinical benefit of the smaller incision [315]. No studies have convincingly shown that minimally invasive techniques or newer technologies, such as patient-specific instrumentation, can lead to improved outcomes or decreased complications in total knee arthroplasty [64]. Combining several procedures in a single setting for the treatment of severe knee osteoarthritis accompanied by extra-articular deformity may eliminate the need for multiple surgeries [112]. The total knee arthroplasty should be performed before surgical reconstruction of the foot is undertaken in patients with a planovalgus foot [115]. The primary repair of iatrogenic medial collateral ligament injury during total knee arthroplasty is a described surgical technique [334].

Implant Selection: Many studies have compared gap balancing versus measured resection techniques, and cruciate retaining versus posterior stabilized implants with essentially equivalent outcomes in terms of pain, function, and survivorship [64]. Cruciate retaining and posterior stabilized total knee arthroplasty techniques both provide good results with no difference in surgical complications, range of motion, patient-reported outcome scores, or implant survivorship [64]. No difference in outcomes or complications exists between posterior stabilized and posterior cruciate retaining designs in total knee arthroplasty [12]. Bicruciate retaining knee arthroplasty has been proposed to preserve intra-articular proprioception and native joint kinematics but has limited adoption due to high early failure rates in some studies [64]. Mobile bearing total knee arthroplasty implants have not demonstrated improved survivorship compared to fixed bearing implants [64]. There is no evidence in support that mobile bearing implants promote greater outcomes compared to fixed bearing implants in primary total knee arthroplasty [272]. Careful attention must be paid to gap balancing when using mobile bearing implants, as bearing spin-out can occur in the presence of a loose flexion gap [64]. All-polyethylene or metal-backed monoblock tibial components have shown good long-term outcomes and are reasonable options for implant choice in total knee arthroplasty [64]. No difference in outcomes exists with the use of all polyethylene or modular tibial components in knee arthroplasty [12]. No difference in pain or function exists with or without patellar resurfacing in total knee arthroplasty [12]. Outcome studies of modern noncemented total knee arthroplasty implants show survivorship and functional outcomes equivalent to cemented prostheses [64]. Similar functional outcomes and complication rates exist in tibial component fixation that is cemented or cementless [12]. There is no evidence to support that fixation techniques alone affect the durability of a total knee arthroplasty when design-related failure was excluded [211]. Uncemented fixation with titanium fiber mesh coating of the femoral component in total knee arthroplasty works equally as well as cemented fixation up to 10 years [245]. Cementless fixation did not decrease the rate of revision after total knee arthroplasty compared with cemented fixation, while long-term functional recovery was significantly better in the cementless group [270]. In a large cohort of primary total knee arthroplasties, patients with cemented fixation reported early incremental benefit in KOOS-Jr. over those with cementless total knee arthroplasty [279]. After a minimum follow-up of 15 years, hybrid fixation of primary total knee arthroplasty for osteoarthritis provides significantly higher clinical benefits compared with cemented fixation, although the differences were not clinically relevant [261].

Alignment / Balancing Strategy: Limb alignment remains an area of controversy in total knee arthroplasty, with studies advocating for both mechanical and kinematic alignment [64]. A recent randomized controlled trial showed no significant difference in functional outcomes at 2 years when comparing mechanical and kinematic alignment techniques in total knee arthroplasty [64]. The balancing goal in total knee arthroplasty is full extension and full flexion of the knee [9]. Unbalanced gaps cause pain from tightness or instability in total knee arthroplasty [9]. The flexion gap in total knee arthroplasty is controlled by the posterior cut of the femur, the tibial cut, and the posterior cruciate ligament [9]. The extension gap in total knee arthroplasty is controlled by the distal cut of the femur, the tibial cut, and the posterior capsule [9]. Posterior capsule recession technique for balancing gaps is performed with the knee flexed at least 90 degrees because the popliteal artery relaxes posteriorly in flexion, making it safer to work posteriorly [9]. For symmetrical gap problems in total knee arthroplasty, the tibia should be addressed first [9]. For asymmetrical gap problems in total knee arthroplasty, the femur should be addressed first [9]. The femoral component should never be internally rotated in total knee arthroplasty [13]. Internal rotation of the femoral component results in relative lateral tilt of the patella and causes the patellar groove to face inward [13]. The technique goal for femoral component rotation is slight external rotation to center the patellar groove under the patella and create a rectangular flexion gap [13]. The native proximal tibia is actually in slight varus, with an average mechanical proximal tibial angle of 3 degrees varus [13]. During total knee arthroplasty, the proximal tibia is cut perpendicular to the mechanical axis, which results in a trapezoidal flexion gap if the femur is not externally rotated [13]. A trapezoidal flexion gap results in relative lateral tilt of the patella, a loose lateral compartment causing instability, or a tight medial compartment causing stiffness [13]. A rectangular flexion gap results in central patella tracking, a balanced flexion gap, and stability without stiffness [13]. The femoral component is externally rotated to compensate for the native tibial varus and obtain a rectangular flexion gap [13]. Five established techniques to determine proper femoral component rotation include the AP axis method, epicondylar axis method, posterior condylar axis method, tibial alignment axis method, and gap balance axis method [13].

Adjuncts: Evidence supports not using intraoperative navigation because there is no difference in pain or complications in total knee arthroplasty [12]. Evidence supports not using patient specific instrumentation compared to conventional instrumentation for total knee arthroplasty because there is no difference in pain or functional outcomes [12]. Evidence supports not using a drain with total knee arthroplasty because there is no difference in complications or outcomes [12]. No difference in aseptic loosening or revision rates at midterm follow-up exists comparing standard total knee arthroplasty instrumentation with patient-specific instrumentation, digitally navigated total knee arthroplasty, or robotic-assisted total knee arthroplasty [12].

Complications

Infection (PJI): Periprosthetic joint infection (PJI) is the most common indication for secondary total knee arthroplasty revision and the primary cause of early revision in contemporary practice [60, 59, 391]. The incidence of PJI after primary total knee replacement ranges from 0.4% to 2% [358]. Revisions for infection are four times more likely to fail than revisions for aseptic loosening [318, 378], with infection accounting for 46% of predominant revision failure modes [318]. Risk factors include a history of treated PJI, which increases the risk of subsequent different-site infection [359], and aseptic reoperation within one year of primary arthroplasty [361]. Primary arthroplasty in patients with resolved prior bone or joint sepsis carries a periprosthetic infection rate of 9.7% [353]. Patients with rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis have higher revision rates due to immune inhibitors and altered immune responses [59], while those with rheumatoid arthritis specifically exhibit higher rates of deep periprosthetic infections compared to osteoarthritis patients [404]. Acute, traumatic wound dehiscence is associated with a 6.5-fold increased risk of PJI [424].

Aseptic loosening: Aseptic loosening is the number two reason for revision and the primary cause of late revision in contemporary total knee arthroplasty [59, 391]. Cementless fixation is an independent risk factor for aseptic loosening requiring revision within two years [399], and primary arthroplasty using high-viscosity cement is associated with higher odds of revision for aseptic loosening [354]. Isolated and full component revision for aseptic loosening do not differ regarding prosthesis failures, complications, or clinical results at five years [337]. Only 4.3% of knees revised for aseptic loosening required rerevision, compared to 21% of knees revised for infection [318].

Instability: Instability results in abnormal excessive limb subluxation or angulation with weight-bearing stress and requires a new implant system to provide additional mechanical support [59]. Internal rotation of the femoral implant is a known cause of flexion gap imbalance [59]. A tibial implant axis lying medial to the tibial tubercle indicates malalignment [59]. Meta-regression estimates raise concerns for significant revision risk with varus-valgus constraint in primary total knee arthroplasty, especially beyond five years [426]. Conversely, the cumulative incidence of subsequent revision for aseptic loosening and instability was very low at five years with a fixed-bearing varus-valgus constraint implant in revision total knee arthroplasties [350].

Patellar / Extensor-mechanism: A trapezoidal flexion gap results in relative lateral tilt of the patella, a loose lateral compartment leading to instability, or a tight medial compartment leading to stiffness [13]. The native proximal tibia is in slight varus with an average medial proximal tibial angle of 3 degrees, resulting in a trapezoidal flexion gap if the femoral component is not externally rotated [13]. The femoral component should be externally rotated 3 to 5 degrees to compensate for native tibial varus and create a rectangular flexion gap [13]. Patellar resurfaced total knee arthroplasty has demonstrated superior overall performance with a lower rate of postoperative anterior knee pain and reoperation [419], although there is no difference in pain or function with or without patellar resurfacing [12]. In a study of 165 patients after total condylar knee arthroplasty, eight knees (4%) had a patellar fracture one to sixty-six months postoperatively [89]. The patellar component was removed from one knee because the component was subluxated and had fractured [89]. Quadriceps strength impairment is observed in the mid- to long-term follow-up period after total knee arthroplasty [108].

Stiffness / Arthrofibrosis: Post-operative stiffness continues to be the most common reason for re-operation after primary posterior-stabilised total knee arthroplasty [293]. Malposition and/or malalignment of implants typically presents with knee stiffness and activity-related pain [59]. In a study of total knee arthroplasty after high tibial osteotomy, three knees (9.1%) required manipulation under anesthesia for stiffness [252].

Thromboembolism: Venous thromboembolism (VTE) after elective total joint arthroplasty continues to occur despite various strategies in prophylaxis and should not be considered a 'never event' [384]. Elective total knee arthroplasty is associated with a higher incidence and odds of inpatient pulmonary embolism than total hip arthroplasty [373]. Multiple procedures pose the highest risk for pulmonary embolism and associated mortality [373]. Prior venous thromboembolism significantly increased the risk of 90-day DVT, PE, and 2-year PJI after total knee arthroplasty [356]. Periprosthetic joint infection is associated with an increased risk of venous thromboembolism following revision total knee replacement [389]. Treatment with dalteparin or dabigatran was associated with a decreased 90-day risk of VTE following primary total knee arthroplasty surgery compared with treatment with rivaroxaban [375]. In 3512 primary total joint arthroplasty patients treated with aspirin, the cumulative incidence of VTE was <1% at 90 days [365]. Patients with a prior VTE episode receiving aspirin thromboprophylaxis following primary total joint arthroplasty had comparable odds of developing DVT and lower odds of experiencing PE relative to patients receiving other types of anticoagulation [381]. No differences were found in the incidence, location, or characteristics of DVT following total knee arthroplasty with or without pharmacological prophylaxis [371]. The use of a tourniquet in primary total knee arthroplasty does not increase the risk of venous thromboembolism within 90 days of surgery [387].

Nerve palsy: In a study of total knee arthroplasty after high tibial osteotomy, one knee (3%) had a common peroneal nerve palsy postoperatively which resolved after three months spontaneously [252].

Wound complications: In a study of total knee arthroplasty after high tibial osteotomy, one knee (3%) had an intraoperative patellar tendon avulsion which was managed by direct repair and fixation [252].

Polyethylene wear: Early modular bearing exchange for premature polyethylene failure has a failure rate of 30% to 40% if the problem causing excessive wear is not corrected [302]. Tibial polyethylene bearings should last at least 13 to 15 years in a well-balanced knee, and bearing failure at 5 to 8 years is considered premature and worrisome [302]. The proportion of revisions for osteolysis and polyethylene wear was higher for primary total knee arthroplasties performed prior to 2000, while revisions for infection and instability were higher for those performed after 2000 [322].

Other Considerations: PJI remains a serious complication of arthroplasty [405]. The survivorship for revision knee arthroplasty, with revision for any reason as an end point, was 82% at 12 years [318]. Re-revision knee arthroplasty carried a high risk of early failure [383]. Repeat two-stage revision for recurrent knee PJI yields low infection control rates and major morbidity, including a 23% amputation rate [398]. Over 20% of patients with multiple arthroplasties and a single PJI will develop a subsequent PJI in another arthroplasty, with 12% recurring in the initial arthroplasty and nearly 10% occurring in another arthroplasty [415]. A longer interval between infection and total joint arthroplasty reduced the risk of PJI, and two-stage arthroplasty was associated with a higher rate of PJI [320]. The prevalence of infection after total knee replacements in patients with hemophilia was high [413]. In a cohort of 129 total knee arthroplasties for Charcot joint, the most frequently reported complications were instability (n=9), aseptic loosening (n=8), periprosthetic fracture (n=8), and PJI (n=6) [313]. Extended antibiotic prophylaxis in total knee arthroplasty was not associated with reduced PJI rates in both normal and high-risk patients at two years [414]. Single-dose prophylactic antibiotics did not lead to an increased risk of acute PJI or short-term complications after total joint arthroplasty [422]. The use of vancomycin as the perioperative prophylactic antibiotic for primary total joint arthroplasties appeared to be effective in decreasing the rate of PJI and may result in infections with less virulent organisms [393]. Intraosseous regional prophylactic antibiotics decrease the risk of prosthetic joint infection in primary total knee arthroplasty [423]. Patient-associated modifiable risk must be optimized to decrease periprosthetic joint infection rates after total knee arthroplasty [418]. The incidence of PJI is increasing due to an increase in the numbers of primary arthroplasties and due to an increase in PJIs occurring within 90 days [396]. In a single surgeon's experience at a county run teaching hospital, a new protocol dropped total joint infection rates from 12.9% to 1.9% [312].

Acute and chronic infection is the most common indication for modular and non-modular component revision, respectively [293]. Revision total knee arthroplasty was more likely to fail in younger patients and in those who underwent polyethylene exchanges [318]. Patients less than 55 years undergoing revision total knee arthroplasty have a modest 5-year revision-free survival of 80% [402]. Survival rates decreased with time, particularly more than 10 years post-surgery, for both primary and revision total knee arthroplasties [401]. In a survivorship analysis of total condylar knee arthroplasty, revision was performed in five knees, with causes including septic loosening, aseptic loosening, and patellar component subluxation/fracture [89]. Eight knees (4%) had a patellar fracture and three knees (2%) had a supracondylar fracture in a survivorship analysis of total condylar knee arthroplasty [89]. Revision arthroplasty is associated with lower outcome and higher infection rate compared to primary replacements [370]. Patients undergoing revision arthroplasty for urgent indications (infection or fracture) are at higher risk of mortality and serious adverse events in comparison to primary knee arthroplasty and revision arthroplasty for elective indications [411]. The incidence of early post-operative morbidity after aseptic knee revisions is similar to that reported after primary procedures [332]. Revision total knee arthroplasty results in a similar QALY gain as primary total knee arthroplasty [70]. Survivorship of aseptic conversion total knee arthroplasty from unicompartmental knee arthroplasty was similar to that of primary total knee arthroplasty for up to 10 years and significantly better than that of first-time revision total knee arthroplasty [336]. Revision free survivorship and arthroplasty related complications at two years following revision unicompartmental knee arthroplasty are lower than that for primary total knee arthroplasty, but higher than that for aseptic revision total knee arthroplasty [366]. Implant survival and clinical outcomes of unicompartmental knee arthroplasty revisions to total knee arthroplasty were inferior to primary total knee arthroplasty [440]. Registries have consistently shown lower implant survival for unicompartmental knee arthroplasty compared with that for total knee arthroplasty [436]. The UKA group had earlier, but less frequent, revision to total knee arthroplasty compared to valgus-producing proximal tibial osteotomy [438]. No difference in aseptic revision risk for the index knee was observed when comparing patients who had a prior primary arthroplasty in a different joint to those who did not have an arthroplasty history [352]. A high percentage of patients undergoing early revision arthroplasty had at least 1 modifiable risk factor for a primary joint arthroplasty [400]. Revisions performed within the first 24 months after primary arthroplasty had a higher rate of any-cause failure [317]. In a study of 566 index revision knee arthroplasties, 12.0% failed at an average of 40.1 months [318].

In a study of total knee arthroplasty after distal femoral osteotomy, there was a high complication rate secondary to problems with balancing the knee [368]. Ten-year survivorship free from aseptic loosening was 95% with reliable improvement in clinical function after total knee arthroplasty following distal femoral osteotomy [368]. In a study of total knee arthroplasty after high tibial osteotomy, complications were reported in 21.2% of knees [252]. Prior knee surgery is a clinical condition predisposed to a higher postoperative complication rate in primary total knee arthroplasty compared to the no prior surgery group [340].

Complications associated with failure of the primary knee arthroplasty prior to arthrodesis included infection in 65%, mechanical problems in 9%, wound-healing problems in 7%, extensor mechanism disruption in 5%, soft tissue deficiency in 5%, aseptic loosening in 4%, pain in 4%, stiffness in 3%, and periprosthetic fracture in 2% [284]. The mean number of surgical procedures between the primary arthroplasty and the arthrodesis was 2.4, including soft-tissue surgery in 66% and revision arthroplasty in 72% of patients [284]. Femorotibial fusion was achieved in 75.0% of cases in a study of knee arthrodesis after failed total knee arthroplasty, with post-operative complications occurring in 46.5% of cases [297]. Two patients eventually required above-the-knee amputation after knee arthrodesis for failed total knee arthroplasty [297]. Above-the-knee amputation after total knee replacement has a reported prevalence of 0.14% to 0.18% [73]. Eight knees (32%) had a complication after above-the-knee amputation following total knee replacement, including five deep infections, one superficial infection, one case of skin necrosis, and one perioperative death [73].

Recovery

Light activity (weeks): Patients undergoing primary total knee arthroplasty (TKA) typically return to driving considerably earlier than previously reported [80]. While return to driving is highly variable, it most commonly occurs around 4 weeks, with a range between 2 and 8 weeks [152]. For right knee replacements, driving may be resumed at 4 weeks, provided the patient drives at low or moderate speed; step counts serve as the best predictor of safe driving [135]. Advice regarding return to driving following hip or knee arthroplasty must be individualized, as the patient must feel safe to drive while maintaining legal responsibility for vehicle control [181]. These results provide guidelines for surgeons advising patients on resuming driving, though individualized assessment remains essential [269].

Full activity (months): Most patients can expect to resume physical activity or sports within a short timeframe after knee arthroplasty, particularly low-impact activities [407]. Findings from the literature serve as a basis for answering patient questions regarding the timing and recommendations for returning to sports following standard primary TKA [259]. Return to physical activity is achievable after revision TKA in the same proportion as after primary TKA, although it occurs later [420]. If working pre-operatively, patients aged < 50 years invariably returned to work following TKA, but only half of those aged between 50 to 60 years returned [248]. One third of working patients never returned to work after TKA [274]. Eighty-six percent of patients return to duty following total joint arthroplasty [209].

Complete recovery / outcome plateau (months): Recovery in knee range of motion reaches a plateau by 12 months after total knee arthroplasty [251]. The maximum Oxford knee score is achieved at two years post-operatively, followed by a gradual decline over ten years [433]. These findings demonstrate a trend toward improvement in cardiovascular fitness one year after total knee arthroplasty and a significant improvement two years postoperatively for patients who had been able to resume routine functional activities because of the arthroplasty [409].

Rehabilitation protocol: The group recommends, by consensus opinion, early mobilization for patients following elective hip and knee arthroplasty [213]. Postoperative physical therapy remains an essential component of standard care following total joint arthroplasty, but the specific approach should be individualized [231]. Future rehabilitation protocols should consider the replaced knee and also the non-replaced knee and surrounding joints [52]. The early physical activity parameters of patients after total knee arthroplasty following the outpatient surgery pathway were similar to those following the standard enhanced recovery pathway [193]. There seems to be an additional need for postoperative rehabilitation after fast-track total knee arthroplasty and unicompartmental knee arthroplasty regarding early functional outcome [236]. Clinically relevant is that the training programme could be considered an alternative to continuous passive motion after total knee arthroplasty [227]. Many observed changes in the knee outcome measures exceeded the MDC thresholds, indicating clinically meaningful benefits from later-stage exercise interventions post-TKA [233]. While prehabilitation has the potential to optimize outcomes for total knee arthroplasty patients, further research from diverse populations is essential to establish robust evidence-based clinical guidelines and uncover optimal interventions for at-risk populations [207]. In the rehabilitation period and at the short and mid-term follow-up, no relevant clinical and radiographic differences were found between the MMV and the conventional approach for total knee arthroplasty, making the advantage of MMV total knee arthroplasty cosmetic [223]. Simultaneous bilateral total knee replacement was associated with a similar reduction of pain intensity and recovery of function compared to unilateral total knee replacement, suggesting the use of simultaneous bilateral total knee replacement in patients with bilateral knee osteoarthritis since its costs and rehabilitation process could be reduced compared to staged bilateral total knee replacement [226].

Functional milestones: Good early outcomes, as measured by the OKS and EQ-5D, can be anticipated following knee replacement regardless of the patient's age, although younger patients gain greater improvement [44]. The functional status of a large cohort of patients significantly improved after hip and knee replacement based on routine data collection [417]. Patients who have undergone total knee replacement demonstrate a response shift in the measurement of their outcome at six months postoperatively [192]. Preoperative exercise of the arthritic knee facilitates immediate postoperative recovery following primary TKA [185]. The ability to kneel was important to patients and significantly influenced knee-specific PROMs, but was poorly restored by TKA with equal chances of improvement or decline [421]. Clinically, functional improvements in patients following total knee arthroplasty may be assessed by objectively measuring changes in low intensity activity behaviors [210].

Other Considerations: Primary TKAs in patients with AS resulted in significant improvement in clinical outcomes with excellent 10-year implant survivorship [74]. In the United States, blacks and individuals with low income undergo total knee replacement less frequently and generally have higher rates of adverse outcomes following primary knee replacement [67]. Same-day total joint arthroplasty is expected to become an everyday procedure for most patients, driven by equivalent or improved patient-reported outcomes and financial incentives, provided appropriate patient selection, optimization, and clinical pathways are followed [275]. Patient-reported outcome measures prior to primary knee arthroplasty were comparable across hospitals with differing revision rates [68].

Key Evidence

• [L4] [1] (10.5435/jaaos-d-18-00083)
• [L2] The main objective of total knee arthroplasty is to ensure the best possible outcome for the patient. [2] (10.1016/j.arth.2024.10.056)
• [L5] The goal of total knee arthroplasty remains delivering the best possible outcome for each individual patient, whether through restoring the native knee or creating the optimal prosthetic knee. [3] (10.1002/ksa.70147)
• [L5] Advancements in total knee arthroplasty require a multifaceted approach that recognizes variations in knee morphometry and phenotypes, as not all knees are the same. [4] (10.1302/0301-620x.106b12.bjj-2023-1269.r1)
• [L2] This inventory review identifies a wide variety of definitions for poor outcome after total knee arthroplasty, highlighting the lack of consensus and the need for standardized definitions to improve comparability across studies. [5] (10.1186/s12891-020-03406-y)
• [L4] Total knee arthroplasty done in young and presumed active patients less than 65 years have excellent survivorship. [6] (10.5435/jaaosglobal-d-22-00116)
• [L4] With careful attention to specific patient and anatomic indications, unicompartmental knee arthroplasty offers clinical results and survivability that are as good, or better, than total knee arthroplasty. [8] (10.1016/j.csm.2013.06.005)
• [L5] For the vast majority of patients, a standard conventional total knee arthroplasty with a familiar surgical approach and standard components leads to satisfactory long-term clinical outcomes, and there is no single 'best' way to perform the procedure. [15] (10.1016/j.arth.2020.04.031)
• [L1] The present meta-analysis encourages the use of minimally invasive techniques for total knee arthroplasty. [16] (10.1007/s00167-020-06306-9)
• [L5] Total knee arthroplasty should be considered as the last surgical option. [17] (10.1007/s00167-017-4466-1)
• [L3] These patients should not be contraindicated from undergoing unicompartmental knee arthroplasty. [18] (10.1007/s00167-018-5169-y)
• [L5] In recent years, evidence suggests that many of the originally described contraindications to unicompartmental knee arthroplasty (UKA) are no longer applicable in modern clinical practice. [19] (10.1016/j.arth.2024.10.043)
• [L2] The indication criteria for THA/TKA are based on limited evidence. [21] (10.1186/s12891-016-1325-z)
• [L3] Expanded indications for unicompartmental knee arthroplasty were associated with comparable clinical outcomes and great short-term, albeit limited, survivorship. [22] (10.1016/j.arth.2025.08.005)
• [L5] A complete and accurate history, physical examination, and radiographic assessment are critical for determining a specific diagnosis and treatment plan for pain after total knee replacement. [23] (10.2106/00004623-200300001-00006)
• [L1] Navigated knee replacement provides few advantages over conventional surgery on the basis of radiographic end points. [24] (10.2106/00004623-200708000-00031)
• [L3] [25] (10.2106/jbjs.19.00432)
• [L5] Total knee replacement cannot be seen as an isolated intervention without considering the many other factors that contribute to outcomes. [26] (10.2106/jbjs.20.02260)
• [L1] The guideline provides 16 recommendations and seven options based on a systematic review of over 1,500 full-text articles to assist surgeons in the surgical management of osteoarthritis of the knee. [27] (10.5435/jaaos-d-23-00338)
• [L4] The use of knee arthroplasty should be thoroughly monitored with more emphasis on standardization in the decision-making process and preventive measures. [28] (10.1186/s12891-019-2766-y)
• [L5] Amongst specialized knee revision surgeons, there is high variability in clinical and radiological criteria that are seen as important contributing factors to diagnosis of knee implant loosening. [30] (10.1002/ksa.12419)
• [L4] Megaprosthesis implantation in revision knee arthroplasty is an exceptional indication. [31] (10.1007/s00167-012-1945-2)
• [L5] Revision total knee arthroplasty is a challenging procedure requiring a correct diagnosis of the original cause of failure and a detailed plan. [32] (10.1302/2058-5241.6.210018)
• [L3] In case of failed arthroplasty after total knee arthroplasty, data did not allow definite treatment recommendations. [33] (10.1016/j.arth.2020.04.078)
• [L4] Although the role for MRI in the postarthroplasty knee has yet to be clearly defined, its utility in working up a painful arthroplasty when history, physical examination, and other diagnostic utilities fail to provide answers is clearly demonstrated in this case. [34] (10.1016/j.arth.2010.01.004)
• [L5] The Appropriate Use Criteria provide guidance for the surgical management of osteoarthritis of the knee, helping clinicians determine the appropriateness of various surgical options based on patient-specific factors. [35] (10.2106/jbjs.16.01484)
• [L5] Most patients can be successfully treated with total knee arthroplasty, but a certain number remain unhappy, requiring careful analysis of whether symptoms are surgery-related or patient-related. [36] (10.1007/s00167-011-1545-6)
• [L1] The findings provide insights into the function of different knee arthroplasty designs during deep kneeling and may allow improved management of patients' functional expectations. [37] (10.1302/0301-620x.103b1.bjj-2020-0958.r1)
• [L5] [39] (10.1016/j.arth.2015.05.049)
• [L5] [41] (10.1007/s00167-019-05462-x)
• [L3] [42] (10.2106/00004623-199311000-00020)
• [L5] The authors acknowledge that this diagnosis is not a universally accepted indication for revision total knee surgery and that further data must be collected regarding long-term outcomes. [43] (10.5435/jaaosglobal-d-24-00399)
• [L3] Good early outcomes, as measured by the OKS and EQ-5D, can be anticipated following knee replacement regardless of the patient's age, although younger patients gain greater improvement. [44] (10.1302/0301-620x.95b1.28061)
• [L5] The panel reached consensus on 18 critical clinical questions spanning general principles, total hip arthroplasty, and total knee arthroplasty. [45] (10.1186/s42836-026-00427-1)
• [L3] The distribution of functional phenotypes of the knee in patients undergoing total knee arthroplasty is different from those found in a reference non-osteoarthritic population. [46] (10.1007/s00167-021-06687-5)
• [L3] A small but clinically significant minority of people continued to have high pain levels at 3-, 12- and 36-months following a primary total knee replacement for osteoarthritis. [47] (10.1186/s12891-022-05800-0)
• [L5] The optimal surgical treatment of knee osteoarthritis in the young and active patient is still insufficiently defined, requiring a compromise between pain relief, functional restoration, and treatment durability. [48] (10.1007/s00167-006-0195-6)
• [L1] Long-term patient-reported outcome measures for total knee and hip arthroplasty beyond one or two years are often incomplete and lose sensitivity. [49] (10.1302/0301-620x.107b3.bjj-2024-0910.r1)
• [L5] Nearly 20% of patients are dissatisfied following well-performed total knee arthroplasty with good functional outcomes, often due to unfulfilled expectations. [51] (10.5435/jaaos-d-14-00049)
• [L3] Future rehabilitation protocols should consider the replaced knee and also the non-replaced knee and surrounding joints. [52] (10.1016/j.arth.2015.06.052)
• [L3] In salvage total knee arthroplasty the implant design does not significantly affect the overall functional outcome. [53] (10.1007/s00167-003-0401-8)
• [L1] Although studies reported a relatively low overall rate of HO after a primary TKA, the absence of a single, standardized classification system precludes the comparisons of HO severity between studies. [54] (10.5435/jaaosglobal-d-21-00096)
• [L3] Total knee arthroplasty among nonagenarians can be performed more safely than previously reported with a perioperative morbidity and mortality that is acceptable to both patient and surgeon. [56] (10.1016/j.arth.2014.09.017)
• [L4] Total knee arthroplasty can be performed safely with low infection rates and good functional outcomes in end-stage renal failure patients provided careful patient selection is in place, specifically excluding those with stroke or peripheral vascular disease. [57] (10.1016/j.arth.2015.07.019)
• [L4] PJI is the most common indication for secondary TKA revision and within one year after primary TKA. [60] (10.1186/s12891-018-2314-1)
• [L2] In the United States, blacks and individuals with low income undergo total knee replacement less frequently and generally have higher rates of adverse outcomes following primary knee replacement. [67] (10.2106/jbjs.d.02546)
• [L2] Patient-reported outcome measures prior to primary knee arthroplasty were comparable across hospitals with differing revision rates. [68] (10.1007/s00167-023-07374-3)
• [L2] Revision total knee arthroplasty results in a similar QALY gain as primary total knee arthroplasty. [70] (10.1002/ksa.12343)
• [L4] [72] (10.5435/00124635-199909000-00004)
• [L3] [73] (10.2106/00004623-200306000-00003)
• [L4] Primary TKAs in patients with AS resulted in significant improvement in clinical outcomes with excellent 10-year implant survivorship. [74] (10.1016/j.arth.2020.06.033)
• [L2] Overall, patients undergoing primary TKA returned to driving considerably earlier than previously reported. [80] (10.2106/jbjs.24.01177)
• [L4] [89] (10.2106/00004623-199274030-00009)
• [L3] When TKA was used for appropriate indications, high BMI should not be considered as a contraindication. [104] (10.1186/s12891-022-05634-w)
• [L2] [108] (10.1007/s00167-016-4333-5)
• [L4] Combining several procedures in a single setting for the treatment of severe knee osteoarthritis accompanied by extra-articular deformity may eliminate the need for multiple surgeries. [112] (10.1007/s00167-018-4920-8)
• [L3] Conventional surgical technique allows a precise joint line reconstruction in primary TKA. [114] (10.1007/s00167-013-2580-2)
• [L4] The total knee arthroplasty should be performed before surgical reconstruction of the foot is undertaken. [115] (10.2106/jbjs.e.00484)
• [L1] For the vast majority of patients, a standard conventional total knee arthroplasty with a surgical approach familiar to the surgeon using standard well-established components, with or without tourniquet, without surgical drain leads to satisfactory long-term clinical outcomes. [116] (10.1016/j.arth.2020.01.065)
• [L4] Presence of diagnosis codes for both knee OA and obesity are risk factors for knee arthroplasty following knee arthroscopy in patients 50 years and older. [123] (10.1016/j.arthro.2025.03.007)
• [L3] Several countries' DRG system might be improved through the introduction of classification variables for revision of knee replacement or for the presence of complications or comorbidities. [124] (10.1007/s00167-013-2374-6)
• [L5] [126] (10.1016/j.arth.2007.01.001)
• [L4] Patellar thickness affects patellofemoral kinematics after TKA. [132] (10.1007/s00167-012-2312-z)
• [L5] Kinematically aligned TKA better restores patellar kinematics and PF contact pressure distribution to the native condition than mechanically aligned TKA during deep knee flexion. [133] (10.1007/s00167-018-5270-2)
• [L5] [134] (10.1016/j.arth.2015.03.042)
• [L4] Driving may be resumed 4 weeks after a right knee replacement but had to drive at low or moderate speed, and the best predictor of safety driving is step counts. [135] (10.1186/1471-2474-15-198)
• [L4] [137] (10.1007/s00167-011-1634-6)
• [L4] [140] (10.1186/s12891-024-08071-z)
• [L1] Kinematic alignment restored native patellar tracking patterns more closely compared to mechanical alignment. [141] (10.1002/ksa.12335)
• [L3] Almost a third of the patients continued to have residual knee pain at 2 years post-TKA, with factors such as gender, presence of ischaemic heart disease, and implant type significantly associated with the development of residual knee pain and/or poorer functional outcome scores. [143] (10.1007/s00167-014-2910-z)
• [L3] More than half the patients presenting for TKA had mild-to-severe contralateral knee pain, most of whom had a clinically meaningful improvement but were significantly less likely to be satisfied with their TKA. [145] (10.1302/0301-620x.102b1.bjj-2019-0328.r1)
• [Paper] Tibial component rotation did not influence patellar kinematics. [147] (10.1007/s00264-014-2507-7)
• [L4] The new classification system for PPF of the femur following TKA considers fracture location and implant type, is easy to use, shows good interobserver reliability, and allows conclusions to be drawn on treatment recommendations. [150] (10.1186/s12891-017-1855-z)
• [L2] Return to driving a car after a primary TKA or THA is highly variable, most commonly occurring around 4 weeks but ranging between 2 and 8 weeks. [152] (10.1155/2020/8921892)
• [L3] The KSPQ is a valid questionnaire to assess patients' expected and desired outcomes of knee replacement surgery and their perception of their current abilities and function, and discrepancy between these. [157] (10.1007/s00167-014-3432-4)
• [L5] Improvement in knee pain after total knee arthroplasty is associated with a reduction in pain in other bodily regions, suggesting a potential physiological link, though persistent pain remains common and improvement does not equate to cure. [159] (10.2106/jbjs.23.00839)
• [L3] Patients from different countries have different expectations regarding total knee arthroplasty, which are not fully explained by differences in sociodemographic factors, clinical characteristics, and pain and functional status. [160] (10.2106/jbjs.e.00147)
• [L5] None of the analysed surgical patellar interventions could restore natural patellar kinematics after TKA. [161] (10.1016/j.arth.2014.07.008)
• [L3] This study has defined a post-operative classification of excellent, good, fair and poor for the components and total WOMAC scores after TKA. [164] (10.1007/s00167-018-4879-5)
• [L3] With careful patient selection, bilateral knee replacement under a single anaesthetic would be a suitable option for patients who present with bilateral symptomatic arthritis of the knee. [165] (10.1007/s00167-006-0196-5)
• [L3] Pain symptoms of moderate or severe pain are unequivocal when considering a TKA. [166] (10.1007/s00167-015-3961-5)
• [L3] Clinically, elderly patients undergoing hip or knee replacement surgery should perform well in terms of preoperative and perioperative management. [168] (10.1186/s12891-025-08742-5)
• [L3] Routine pathological examination of surgical specimens from patients undergoing primary total hip or knee replacement because of the clinical diagnosis of osteoarthritis had limited cost-effectiveness at our hospital due to the low prevalence of findings that altered patient management. [170] (10.2106/00004623-200011000-00002)
• [L3] The estimated lifetime risk of revision knee arthroplasty varied depending on patient sex, age, and underlying diagnosis. [171] (10.1302/0301-620x.104b12.bjj-2021-1631.r3)
• [L5] The AAOS Appropriate Use Criteria (AUC) for Surgical Management of Osteoarthritis of the Knee, developed by a voting panel reviewing 864 scenarios, categorize treatments as Appropriate, May Be Appropriate, or Rarely Appropriate based on specific clinical scenarios to assist in decision-making. [174] (10.5435/jaaos-d-17-00425)
• [L4] ED visits following elective major joint replacement were numerous and most commonly for pain-related diagnoses. [175] (10.2106/jbjs.16.00692)
• [L3] Patients aged 68 years or older experience deterioration in functional outcomes and quality of life from 2 to 10 years after total knee arthroplasty. [176] (10.1007/s00167-020-06200-4)
• [L4] The unstable TKA may result from a variety of distinct etiologies which must be identified and treated at the time of revision. [177] (10.1016/j.arth.2013.06.023)
• [L3] Surgical timing preferences for knee replacement vary between patients older than 65 years (immediate surgery only when pain is intense) and younger patients (immediate surgery no matter the amount of pain). [178] (10.1007/s00167-021-06611-x)
• [L5] Recent reports have demonstrated success in expanding the classic indications of unicompartmental knee arthroplasty to younger and heavier patients. [179] (10.5435/jaaos-d-24-00380)
• [L5] Advice regarding return to driving following hip or knee arthroplasty should be individualized for each patient; ultimately the patient must feel safe to drive knowing that they have a legal responsibility to remain in control of the vehicle at all times. [181] (10.1016/j.arth.2022.10.024)
• [L5] The authors argue that classifications of good versus poor outcome following knee arthroplasty should not be defined using arbitrary cutoff scores, as this homogeneity impedes scientific progress, and instead propose relying on non-biased statistical model-based approaches. [182] (10.1186/s12891-020-03583-w)
• [L1] Preoperative exercise of the arthritic knee facilitates immediate postoperative recovery following primary TKA. [185] (10.1007/s00167-012-2349-z)
• [L1] Patients who have undergone total knee replacement demonstrate a response shift in the measurement of their outcome at six months postoperatively. [192] (10.2106/jbjs.f.00283)
• [L3] The early physical activity parameters of patients after total knee arthroplasty following the outpatient surgery pathway were similar to those following the standard enhanced recovery pathway. [193] (10.1007/s00167-016-4256-1)
• [L3] Absolute and relative differences in knee dimensions exist between Asian and Caucasian knees, and not all TKA systems fit these phenotypes well. [196] (10.1007/s00167-020-05914-9)
• [L1] In patients with knee osteoarthritis, total knee replacement plus a 12-week nonsurgical treatment program was more effective than nonsurgical treatment alone but was associated with more serious adverse events. [204] (10.2106/jbjs.16.00208)
• [L3] When applying the modified joint line obliquity classification, postoperative joint line obliquity was associated with high survival rates following total knee arthroplasty at a mean follow-up of 12.7 years. [206] (10.1016/j.arth.2025.10.114)
• [L5] While prehabilitation has the potential to optimize outcomes for total knee arthroplasty patients, further research from diverse populations is essential to establish robust evidence-based clinical guidelines and uncover optimal interventions for at-risk populations. [207] (10.1016/j.arth.2024.12.021)
• [L3] Eighty-six percent of patients return to duty following total joint arthroplasty. [209] (10.1016/j.arth.2013.02.028)
• [L2] Clinically, functional improvements in patients following total knee arthroplasty may be assessed by objectively measuring changes in low intensity activity behaviors. [210] (10.1007/s00167-018-4987-2)
• [L1] There is no evidence to support that fixation techniques alone affect the durability of a total knee arthroplasty when design-related failure in TKAs was excluded. [211] (10.1007/s00167-013-2806-3)
• [L4] Therefore, if patients present with negative predictor factors, the AM should not be proposed as second-line treatment, and nonoperative management should be continued until TKR is unavoidable. [212] (10.1016/j.arthro.2020.11.053)
• [L4] Good-to-excellent outcomes can be achieved following UKA and TKA in patients less than 65 years of age, with both procedures not contraindicated at younger age. [214] (10.1007/s00167-017-4817-y)
• [L5] Personalised medicine in orthopaedics, specifically the concept of 'Functional Knee Phenotypes', goes beyond utilizing implants manufactured based on individual 3D-data and may help to structure and categorize individual morphology and alignment to identify the optimal TKA strategy. [215] (10.1007/s00167-019-05428-z)
• [L4] [216] (10.1016/j.arth.2026.06.061)
• [L2] The indication for TKA should consider the general health, emotional role and knee function of the patients as well in order to predict patient's outcome. [217] (10.1007/s00167-011-1621-y)
• [L3] With arthroplasty registry adoption of patient-reported outcome measures (PROMs), this study supports precise anatomical categorisation of knee OA in outcome studies. [220] (10.1016/j.jisako.2024.01.002)
• [L1] In the rehabilitation period and at the short and mid-term follow-up, no relevant clinical and radiographic differences were found between the MMV and the conventional approach for total knee arthroplasty, making the advantage of MMV total knee arthroplasty cosmetic. [223] (10.2106/jbjs.15.00654)
• [L5] The Unified Classification System proposes a rational approach to treatment regardless of the bone broken or joint involved, aiming to improve understanding and consistency in reporting periprosthetic fractures. [224] (10.1302/0301-620x.96b6.34040)
• [L3] Fractures of knee arthroplasty systems are rare complications, with clinical studies showing higher incidence rates than worldwide arthroplasty registries. [225] (10.1007/s00167-016-4160-8)
• [L3] Simultaneous bilateral total knee replacement was associated with a similar reduction of pain intensity and recovery of function compared to unilateral total knee replacement, suggesting the use of simultaneous bilateral total knee replacement in patients with bilateral knee osteoarthritis since its costs and rehabilitation process could be reduced compared to staged bilateral total knee replacement. [226] (10.1186/s12891-020-03269-3)
• [L2] Clinically relevant is that the training programme could be considered an alternative to continuous passive motion after total knee arthroplasty. [227] (10.1007/s00167-018-4918-2)
• [L5] Postoperative physical therapy remains an essential component of standard care following total joint arthroplasty, but the specific approach should be individualized. [231] (10.1016/j.arth.2024.10.105)
• [L1] Many observed changes in the knee outcome measures exceeded the MDC thresholds, indicating clinically meaningful benefits from later-stage exercise interventions post-TKA. [233] (10.1186/s13018-025-06430-7)
• [L5] This study successfully established a consensus among knee revision surgeons on the definition of intraoperatively determined component loosening. [234] (10.1002/ksa.12357)
• [L2] There seems to be an additional need for postoperative rehabilitation after fast-track total knee arthroplasty and unicompartmental knee arthroplasty regarding early functional outcome. [236] (10.1007/s00167-012-1919-4)
• [L3] However, the incidence of major complications is much higher than with other types of total knee arthroplasty and arthrodesis, so this type of arthroplasty should be reserved for specific clinical situations. [237] (10.2106/00004623-198062040-00004)
• [L4] A complete implant library containing characteristics of 32,500 orthopaedic implants was developed, covering about 85 different hip and 85 different knee implants. [242] (10.1302/2058-5241.4.180063)
• [L1] Uncemented fixation with titanium fiber mesh coating of the femoral component in total knee arthroplasty works equally as well as cemented fixation up to 10 years. [245] (10.1007/s00167-018-5227-5)
• [L3] Based on a low certainty of evidence, MRI and SPECT/CT are currently the most accurate modalities available to aid the diagnosis of aseptic loosening of knee arthroplasty components. [246] (10.1002/ksa.12206)
• [L3] If working pre-operatively, patients aged < 50 years invariably returned to work following TKA, but only half of those aged between 50 to 60 years returned. [248] (10.1302/0301-620x.99b8.bjj-2016-1364.r1)
• [L4] Baseline radiographic severity grade was only associated with future total knee arthroplasty risk in the absence of a full-thickness defect. [249] (10.2106/jbjs.17.01657)
• [L4] Recovery in knee range of motion reaches a plateau by 12 months after total knee arthroplasty. [251] (10.1007/s00167-014-3212-1)
• [L4] [252] (10.1186/s13018-023-04199-1)
• [L5] The findings may serve as a basis for answering patient questions on timing and giving recommendations for returning to sports following standard primary TKA. [259] (10.1007/s00167-020-06400-y)
• [L3] Non-arthroplasty therapies accounted for about one third of the costs in treating knee OA, with HA comprising only a small fraction (3%) of overall costs. [260] (10.1186/s13018-020-01848-7)
• [L3] After a minimum follow-up of 15 years, hybrid fixation of primary TKA for osteoarthritis provides significantly higher clinical benefits compared with cemented fixation, although the differences were not clinically relevant. [261] (10.1007/s00167-020-06028-y)
• [L4] Nonagenarians undergoing primary TKA had low mortality rates at 90 days (0%) and 1 year (2%) with substantial functional improvements. [268] (10.1016/j.arth.2021.05.015)
• [L1] These results may serve as guidelines for orthopaedic surgeons when advising patients when to resume driving, though advice should be individualised. [269] (10.1302/0301-620x.99b5.bjj-2016-1064.r1)
• [L1] Cementless fixation did not decrease the rate of revision after the total knee arthroplasty compared with the cemented fixation, while the long-term functional recovery was significantly better in the cementless group. [270] (10.1186/s13018-021-02299-4)
• [L1] There is no evidence in support that mobile bearing implants promote greater outcomes compared to fixed bearing implants in primary total knee arthroplasty. [272] (10.1007/s00167-022-07065-5)
• [L5] [273] (10.5435/00124635-200307000-00003)
• [L4] One third of working patients never returned to work after TKA. [274] (10.1016/j.arth.2014.01.004)
• [L5] Same-day total joint arthroplasty is expected to become an everyday procedure for most patients, driven by equivalent or improved patient-reported outcomes and financial incentives, provided appropriate patient selection, optimization, and clinical pathways are followed. [275] (10.1016/j.arth.2023.11.018)
• [L1] Patients with mild radiographic osteoarthritis are anticipated to gain less from total knee arthroplasty compared to those with severe osteoarthritis. [278] (10.1007/s00167-021-06487-x)
• [L3] In a large cohort of primary TKAs, patients with cemented fixation reported early incremental benefit in KOOS-Jr. over those with cementless TKA. [279] (10.1186/s12891-022-05899-1)
• [L3] [284] (10.2106/jbjs.15.01363)
• [L4] The use of routinely available preoperative radiology reports provides promising potential to help screen suitable candidates for THA, but not for TKA. [286] (10.1302/0301-620x.106b7.bjj-2024-0136)
• [L4] Standardised radiological imaging, with MRI to exclude overt tibiofemoral disease should be part of the pre-operative assessment, especially for the non-dysplastic knee. [291] (10.1302/0301-620x.95b6.31355)
• [L2] There is preliminary evidence that MRI has a noteworthy value of distinguishing suspected periprosthetic joint infection in patients with total knee arthroplasty or total hip arthroplasty, but the definition of specific MRI features related to PJIs diagnosis lacks consensus and standardization. [292] (10.1186/s12891-023-06926-5)
• [L3] [293] (10.1302/0301-620x.99b5.bjj-2016-0617.r3)
• [L4] [294] (10.1007/s00402-019-03290-9)
• [L2] Radiographic findings including joint space narrowing and MRI detected bone marrow lesions, synovitis and effusion were all significantly associated with the long term risk of TKA in persons with knee osteoarthritis. [296] (10.1186/s12891-017-1871-z)
• [L3] [297] (10.1016/j.arth.2013.09.054)
• [L4] [301] (10.1016/j.arth.2020.02.030)
• [L3] The diagnostic benefits of SPECT/CT in patients after total knee arthroplasty have been proven. [303] (10.1177/2325967116s00051)
• [L3] [307] (10.1016/j.arth.2007.03.025)
• [L3] [312] (10.1016/j.arth.2014.03.012)
• [L4] [313] (10.1016/j.arth.2020.08.008)
• [L3] Routine screening is not necessary, but patients with persistent hip or knee pain should be assessed with MRI. [314] (10.1016/j.arth.2007.01.006)
• [L4] [315] (10.1016/j.arth.2006.12.055)
• [L5] [316] (10.5435/00124635-200211000-00005)
• [L3] Those revisions performed within the first 24 months after primary arthroplasty had a higher rate of any-cause failure. [317] (10.1016/j.arth.2024.07.031)
• [L3] [318] (10.1016/j.arth.2008.04.020)
• [L1] A longer interval between infection and total joint arthroplasty reduced the risk of PJI, and two-stage arthroplasty was associated with a higher rate of PJI. [320] (10.1016/j.arth.2026.06.056)
• [L4] [321] (10.1007/s00167-007-0397-6)
• [L4] The proportion of revisions for osteolysis and polyethylene wear was higher for primary TKAs performed prior to 2000, while revisions for infection and instability were higher for those performed after 2000. [322] (10.1186/s42836-022-00134-7)
• [Case_report] [323] (10.1007/s00167-008-0533-y)
• [Case_report] A thorough preoperative investigation, especially MRI, is required to determine the role of each layer to make the correct decision between fusion, preservation, removal, or resurfacing of the patella. [324] (10.1016/j.jisako.2022.01.004)
• [L5] Tomosynthesis is superior to fluoroscopically guided plain radiography, CT, and MRI for the early detection of small periprosthetic bone defects after total knee arthroplasty in terms of sensitivity, specificity, radiation dose, and cost. [326] (10.1016/j.arth.2014.05.013)
• [L4] Routine radiographic surveillance did not detect any true abnormalities during the first year after primary total joint arthroplasty. [327] (10.1016/j.arth.2021.02.050)
• [L3] In the setting of image-based RA-TKA performed with functional knee positioning, the rotational alignment of the femoral component changes significantly among different knee phenotypes. [328] (10.1002/ksa.12732)
• [L4] Patients can be counselled that although radiographic severity of arthritic changes can predict knee-specific functional improvement, the extent of their global functional improvement cannot. [330] (10.1007/s00167-015-3806-2)
• [L3] The incidence of early post-operative morbidity after aseptic knee revisions is similar to that reported after primary procedures. [332] (10.1302/0301-620x.96b12.33621)
• [L4] A deep learning algorithm using plain radiographs differentiated between 9 unique knee arthroplasty implants from four manufacturers with near-perfect accuracy. [333] (10.1016/j.arth.2020.10.021)
• [L4] [334] (10.1016/j.arth.2014.12.020)
• [L3] Survivorship of aseptic conversion TKA was similar to that of primary TKA for up to 10 years and significantly better than that of first-time revision TKA. [336] (10.1016/j.arth.2025.06.041)
• [L3] Isolated and full component revision TKA for aseptic loosening does not differ with respect to prosthesis failures, complications, and clinical results at 5 years. [337] (10.1016/j.arth.2022.09.006)
• [L3] A low radiological severity of osteoarthritis was not associated with pain 12 months postoperatively. [339] (10.1302/0301-620x.96b11.33726)
• [L4] Prior knee surgery is a clinical condition predisposed to a higher postoperative complication rate in primary TKA compared to the no prior surgery group. [340] (10.1007/s00167-012-2139-7)
• [L4] SPECT/CT was very helpful in establishing the diagnosis and guiding subsequent management in patients with painful knees after TKA, particularly in patients with patellofemoral problems and malpositioned or loose TKA. [341] (10.1186/1471-2474-12-36)
• [L2] The diagnostic benefits of SPECT/CT in patients with pain after primary TKA have been proven, with excellent sensitivity and specificity for detection of tibial or femoral component loosening and patellofemoral OA surgically confirmed. [343] (10.1007/s00167-019-05609-w)
• [L3] The cumulative incidence of subsequent revision for aseptic loosening and instability was very low at five years with this fixed-bearing VVC implant in revision TKAs. [350] (10.1302/0301-620x.102b4.bjj-2019-0719.r2)
• [L3] No difference in aseptic revision risk for the index knee was observed when comparing patients who had a prior primary arthroplasty in a different joint to those who did not have an arthroplasty history. [352] (10.1016/j.arth.2022.08.007)
• [L3] Primary total knee arthroplasty can be performed in patients with resolved prior bone or joint sepsis, but the rate of periprosthetic infection (9.7%) remains a significant concern. [353] (10.1016/j.arth.2014.01.013)
• [L3] Although high-viscosity cement is an attractive option for use in primary total knee arthroplasty, this appropriately controlled study demonstrates higher odds of revision for aseptic loosening when using high-viscosity cement with multiple different implant types. [354] (10.1016/j.arth.2019.08.023)
• [L3] Prior VTE significantly increased the risk of 90-day DVT, PE, and 2-year PJI after TKA. [356] (10.1016/j.arth.2026.02.013)
• [L3] A history of PJI predisposes patients to subsequent PJI in primary THA or TKA. [359] (10.1007/s11999-015-4174-4)
• [L3] Aseptic reoperation within 1 year of primary TKA was associated with a notably increased risk of subsequent PJI. [361] (10.1016/j.arth.2020.06.054)
• [L1] Utilization of this axial weight-bearing view to evaluate total knee arthroplasty may provide additional information over standard radiographic views. [363] (10.2106/jbjs.e.00432)
• [L4] Simultaneous biplane radiography can accurately assess the motion of total joint replacements in vivo and may become an important adjunct in postoperative management to detect early changes before clinical or radiographic evidence of loosening is apparent. [364] (10.2106/00004623-198466040-00028)
• [L3] In 3512 primary TJA patients treated with ASA, we found a cumulative incidence of VTE <1% at 90 days. [365] (10.1016/j.arth.2021.02.007)
• [L3] Revision free survivorship and arthroplasty related complications at two years following revision UKA are lower than that for primary TKA, but higher than that for aseptic revision TKA, whereas medical complications are similar to those following primary TKA. [366] (10.1016/j.arth.2024.12.026)
• [L3] Ten-year survivorship free from aseptic loosening was 95% with reliable improvement in clinical function, though there was a high complication rate secondary to problems with balancing the knee. [368] (10.1302/0301-620x.101b6.bjj-2018-1334.r2)
• [L4] In this study, we describe novel radiographic findings of anterior heterotopic bone formation and cysts that develop in patients who have aseptic loosening following primary total knee arthroplasty. [369] (10.1016/j.arth.2023.01.031)
• [L3] Revision arthroplasty is associated with lower outcome and higher infection rate compared to primary replacements. [370] (10.1155/2018/8987104)
• [L3] No differences were found in the incidence, location, or characteristics of DVT following TKA with or without pharmacological prophylaxis. [371] (10.1186/s12891-021-04707-6)
• [L4] Elective total knee arthroplasty is associated with a higher incidence and odds of inpatient pulmonary embolism than is total hip arthroplasty; multiple procedures pose the highest risk for pulmonary embolism and associated mortality. [373] (10.2106/jbjs.l.00466)
• [L3] Assessment of medial cartilage thickness loss using MRI provides additional utility over standard radiographs in preoperative assessments of medial UKA patients. [374] (10.1002/ksa.12611)
• [L2] Treatment with dalteparin or dabigatran was associated with a decreased 90-day risk of VTE following primary TKA surgery compared with treatment with rivaroxaban. [375] (10.1302/0301-620x.103b10.bjj-2021-0023.r1)
• [L4] In a patient who has an unsatisfactory response to their first knee replacement, the best predictor of achieving a satisfactory response to their contralateral knee replacement is the level of radiographic osteoarthritis in that knee. [376] (10.1007/s00167-021-06465-3)
• [L3] Mild radiographic knee OA was the main predicting factor for dissatisfaction after TKA, suggesting that performing TKA for such patients should be carefully considered. [377] (10.1186/s12891-021-04543-8)
• [L3] Mechanisms of failure for revision total knee arthroplasties are different than for primary total knee arthroplasty, with revisions for infection being 4 times more likely to fail than revisions for aseptic loosening. [378] (10.1016/j.arth.2008.01.228)
• [L3] Patients with a prior VTE episode receiving aspirin thromboprophylaxis following primary TJA had comparable odds of developing DVT and lower odds of experiencing PE relative to patients receiving other types of anticoagulation. [381] (10.1016/j.arth.2025.10.069)
• [L1] To prevent for malalignment, MRI should be the imaging modality of choice when performing TKA surgery with PSI. [382] (10.1007/s00167-017-4637-0)
• [L3] Re-revision knee arthroplasty carried a high risk of early failure. [383] (10.1016/j.arth.2023.01.030)
• [L5] Venous thromboembolism (VTE) after elective total joint arthroplasty continues to occur despite various strategies in prophylaxis and should not be considered a 'never event.' [384] (10.2106/jbjs.21.01529)
• [L5] Improving long-term outcomes after total knee arthroplasty requires moving beyond the static concept of 'correct alignment option' to integrate static images with dynamic and kinetic insights. [385] (10.1002/ksa.70010)
• [L2] In contemporary TKAs the rate of VTE within 90 days is low and not significantly altered by tourniquet-use. [387] (10.1007/s00167-022-06965-w)
• [L3] The indication for revision total knee replacement should be considered when choosing postoperative VTE prophylaxis. [389] (10.2106/jbjs.20.01486)
• [L3] Aseptic loosening and infection are the most common causes of failure in contemporary total knee arthroplasty, with infection being the primary cause of early revision and loosening the primary cause of late revision. [391] (10.1016/j.arth.2013.07.024)
• [L3] Patients undergoing TKR exhibited significantly worse baseline clinical outcomes, particularly in WOMAC scores, despite having similar radiographic severity to those receiving conservative treatment, suggesting that functional and symptomatic measures may be more valuable than radiographic findings in determining surgical intervention. [392] (10.1186/s13018-025-05552-2)
• [L3] The use of vancomycin as the perioperative prophylactic antibiotic for primary total joint arthroplasties appeared to be effective in decreasing the rate of PJI and may result, when they occur, in infections with less virulent organisms. [393] (10.1016/j.arth.2012.03.040)
• [L3] The PJIs are increasing, both because of an increase in the numbers of primary arthroplasties and due to an increase in PJIs occurring within 90 days. [396] (10.1016/j.arth.2026.01.042)
• [L4] The SPECT/CT algorithm presented is both reliable and useful in the management of patients with painful TKA. [397] (10.1007/s00167-010-1070-z)
• [L3] Repeat two-stage revision for recurrent knee PJI yields low infection control rates and major morbidity, including a 23% amputation rate. [398] (10.1016/j.arth.2026.01.057)
• [L3] In this large national database, cementless fixation was found to be an independent risk factor for aseptic loosening requiring revision and any reoperation within 2 years after primary TKA. [399] (10.1016/j.arth.2023.02.058)
• [L3] A high percentage of patients undergoing early revision arthroplasty had at least 1 modifiable risk factor for a primary joint arthroplasty. [400] (10.1016/j.arth.2017.07.005)
• [L3] Survival rates decreased with time, particularly more than 10 years post-surgery, for both primary and revision TKAs. [401] (10.1016/j.otsr.2017.10.003)
• [L3] Patients less than 55 years undergoing revision TKA have a modest 5-year revision-free survival of 80%. [402] (10.1016/j.arth.2020.12.008)
• [L1] Following primary TKA, RA patients had a significantly higher rate of deep periprosthetic infections than OA patients, but their superficial infection rates were similar. [404] (10.1007/s00167-016-4306-8)
• [L2] PJI remains a serious complication of arthroplasty. [405] (10.1302/0301-620x.101b1.bjj-2018-0233.r1)
• [L4] Most patients can expect to resume physical activity or sports within a short timeframe after knee arthroplasty, particularly to low-impact activities. [407] (10.1002/ksa.70267)
• [L3] These findings demonstrate a trend toward improvement in cardiovascular fitness one year after total knee arthroplasty and a significant improvement two years postoperatively for patients who had been able to resume routine functional activities because of the arthroplasty. [409] (10.2106/00004623-199611000-00009)
• [L3] Patients undergoing revision arthroplasty for urgent indications (infection or fracture) are at higher risk of mortality and serious adverse events in comparison to primary knee arthroplasty and revision arthroplasty for elective indications. [411] (10.1302/0301-620x.103b10.bjj-2020-2590.r1)
• [L4] However, the prevalence of infection after the total knee replacements was high. [413] (10.2106/jbjs.c.01609)
• [L3] Extended antibiotic prophylaxis in TKA was not associated with reduced PJI rates in both normal and high-risk patients at two years. [414] (10.1016/j.arth.2025.10.017)
• [L4] Over 20% of the patients with multiple arthroplasties and a single PJI will develop a subsequent PJI in another arthroplasty with 12% recurring in the initial arthroplasty and nearly 10% occurring in another arthroplasty. [415] (10.1016/j.arth.2023.03.014)
• [L4] The functional status of a large cohort of patients significantly improved after hip and knee replacement based on routine data collection. [417] (10.1186/s12891-017-1455-y)
• [L4] Patient-associated modifiable risk must be optimized to decrease periprosthetic joint infection rates after total knee arthroplasty. [418] (10.5435/jaaos-d-16-00635)
• [L1] Based on the main findings of this meta-analysis, patellar resurfaced TKA was demonstrated to have performed superior overall with a lower rate of postoperative anterior knee pain and reoperation. [419] (10.1007/s00402-019-03246-z)
• [L3] Return to physical activity is achievable after revision TKA in the same proportion as after primary TKA, but it occurs later. [420] (10.1002/ksa.12638)
• [L2] The ability to kneel was important to patients and significantly influenced knee-specific PROMs, but was poorly restored by TKA with equal chances of improvement or decline. [421] (10.1302/0301-620x.103b9.bjj-2020-2129.r2)
• [L3] Single-dose prophylactic antibiotics did not lead to an increased risk of acute PJI or short-term complications after TJA. [422] (10.1016/j.arth.2021.02.037)
• [L3] Future randomized prospective clinical trials are needed to validate the efficacy of regional prophylactic antibiotics in reducing the PJI risk in primary TKA. [423] (10.1097/corr.0000000000001919)
• [L3] Acute, traumatic wound dehiscence following primary TKA is a rare event associated with a 6.5-fold increased risk of PJI. [424] (10.1302/0301-620x.103b6.bjj-2020-2425.r1)
• [L1] Meta-regression estimates raise concerns for significant revision risk with extended follow-up, especially beyond 5 years. [426] (10.1016/j.arth.2019.09.048)
• [L3] The maximum Oxford knee score is achieved at two years post-operatively, followed by a gradual decline over ten years. [433] (10.1302/0301-620x.95b1.28573)
• [L4] Registries have consistently shown lower implant survival for UKA compared with that for TKA, which is likely secondary to use of several different implants by surgeons of varying levels of experience. [436] (10.5435/jaaos-d-17-00690)
• [L3] The UKA group had earlier, but less frequent, revision to total knee arthroplasty. [438] (10.2106/jbjs.15.01031)
• [L3] Our data suggest that the implant survival and clinical outcomes were inferior to primary TKA. [440] (10.1302/0301-620x.107b12.bjj-2025-0184.r2)

See Also

• Patellofemoral instability
• Unicompartmental knee replacement
• Knee osteoarthritis
• Knee arthroscopy
• Partial meniscectomy
• High tibial osteotomy
• Medial collateral ligament injury
• Distal femoral osteotomy

References

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[59] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > SECTION 15 REVISION TOTAL KNEE ARTHROPLASTY > PREOPERATIVE EVALUATION.

[60] Periprosthetic infection is the major indication for TKA revision – experiences from a university referral arthroplasty center. BMC Musculoskeletal Disorders. 2018. DOI: 10.1186/s12891-018-2314-1

[64] Orthopaedic Knowledge Update 13 Ebook Without Multimedia. Knee Arthroscopy and Preservation, Knee Reconstruction > Knee Reconstruction > Total Knee Arthroplasty.

[67] Epidemiology of Total Knee Replacement in the United States Medicare Population. The Journal of Bone and Joint Surgery (American). 2005. DOI: 10.2106/jbjs.d.02546

[68] Hospital variation in revision rates after primary knee arthroplasty was not explained by patient selection: baseline data from 1452 patients in the Danish prospective multicenter cohort study, SPARK. Knee Surgery, Sports Traumatology, Arthroscopy. 2023. DOI: 10.1007/s00167-023-07374-3

[69] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > SECTION 17 CATASTROPHIC WEAR IN TOTAL KNEE ARTHROPLASTY.

[70] Similar QALY gain in primary and revision knee arthroplasty: A cost analysis and Markov model. Knee Surgery, Sports Traumatology, Arthroscopy. 2024. DOI: 10.1002/ksa.12343

[72] Aseptic Complications After Total Knee Arthroplasty. Journal of the American Academy of Orthopaedic Surgeons. 1999. DOI: 10.5435/00124635-199909000-00004

[73] ABOVE-THE-KNEE AMPUTATION AFTER A TOTAL KNEE REPLACEMENT. The Journal of Bone and Joint Surgery-American Volume. 2003. DOI: 10.2106/00004623-200306000-00003

[74] Contemporary Primary Total Knee Arthroplasty is Durable in Patients Diagnosed With Ankylosing Spondylitis. The Journal of Arthroplasty. 2020. DOI: 10.1016/j.arth.2020.06.033

[80] Factors That Influence Returning to Driving Following Primary Total Knee Arthroplasty. Journal of Bone and Joint Surgery. 2025. DOI: 10.2106/jbjs.24.01177

[85] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > SECTION 1 KNEE > ANATOMY (FIG. 4.1).

[89] Survivorship analysis in total condylar knee arthroplasty. A statistical review.. The Journal of Bone & Joint Surgery. 1992. DOI: 10.2106/00004623-199274030-00009

[104] Effect of body mass index on symptomatic venous thromboembolism and prosthesis revision risk after total knee arthroplasty: a long-term study from China. BMC Musculoskeletal Disorders. 2022. DOI: 10.1186/s12891-022-05634-w

[108] Quadriceps strength impairment in the mid- to long-term follow-up period after total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2016. DOI: 10.1007/s00167-016-4333-5

[112] Deformity correction with total knee arthroplasty for severe knee osteoarthritis accompanying extra-articular femoral deformity: the results are promising. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-4920-8

[114] Joint line changes after primary total knee arthroplasty: navigated versus non‐navigated. Knee Surgery, Sports Traumatology, Arthroscopy. 2013. DOI: 10.1007/s00167-013-2580-2

[115] The Planovalgus Foot: A Harbinger of Failure of Posterior Cruciate-Retaining Total Knee Replacement. Journal of Bone and Joint Surgery. 2005. DOI: 10.2106/jbjs.e.00484

[116] Overview of Randomized Controlled Trials in Total Knee Arthroplasty (47,675 Patients): What Have We Learnt?. The Journal of Arthroplasty. 2020. DOI: 10.1016/j.arth.2020.01.065

[123] Knee Arthroplasty Risk After Arthroscopy in Patients Older Than Age 50 Years Correlates With the Presence of Diagnosis Codes for Osteoarthritis and Obesity. Arthroscopy. 2025. DOI: 10.1016/j.arthro.2025.03.007

[124] Knee replacement and Diagnosis‐Related Groups (DRGs): patient classification and hospital reimbursement in 11 European countries. Knee Surgery, Sports Traumatology, Arthroscopy. 2013. DOI: 10.1007/s00167-013-2374-6

[126] A Stepwise Approach to Revision Total Knee Arthroplasty. The Journal of Arthroplasty. 2007. DOI: 10.1016/j.arth.2007.01.001

[132] Patellar thickness and lateral retinacular release affects patellofemoral kinematics in total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-2312-z

[133] Kinematically aligned total knee arthroplasty reproduces native patellofemoral biomechanics during deep knee flexion. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-5270-2

[134] The Diagnosis of Periprosthetic Joint Infection. The Journal of Arthroplasty. 2015. DOI: 10.1016/j.arth.2015.03.042

[135] Timeframe for return to driving for patients with minimally invasive knee arthroplasty is associated with knee performance on functional tests. BMC Musculoskeletal Disorders. 2014. DOI: 10.1186/1471-2474-15-198

[137] The painful knee after TKA: a diagnostic algorithm for failure analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2011. DOI: 10.1007/s00167-011-1634-6

[140] Difficulty of diagnostic accuracy of periprosthetic joint infection: a retrospective analysis of revision surgery of total hip arthroplasty and total knee arthroplasty in a tertiary hospital. BMC Musculoskeletal Disorders. 2024. DOI: 10.1186/s12891-024-08071-z

[141] Kinematical alignment better restores native patellar tracking pattern than mechanical alignment. Knee Surgery, Sports Traumatology, Arthroscopy. 2024. DOI: 10.1002/ksa.12335

[143] Residual knee pain and functional outcome following total knee arthroplasty in osteoarthritic patients. Knee Surgery, Sports Traumatology, Arthroscopy. 2014. DOI: 10.1007/s00167-014-2910-z

[145] Contralateral knee pain reduces the rate of patient satisfaction but does not clinically impair the change in WOMAC score after total knee arthroplasty. The Bone & Joint Journal. 2020. DOI: 10.1302/0301-620x.102b1.bjj-2019-0328.r1

[147] Is it possible to re-establish pre-operative patellar kinematics using a ligament-balanced technique in total knee arthroplasty? A cadaveric investigation. International Orthopaedics. 2014. DOI: 10.1007/s00264-014-2507-7

[150] A new classification of TKA periprosthetic femur fractures considering the implant type. BMC Musculoskeletal Disorders. 2017. DOI: 10.1186/s12891-017-1855-z

[152] Clinical Considerations for Return to Driving a Car following a Total Knee or Hip Arthroplasty: A Systematic Review. BioMed Research International. 2020. DOI: 10.1155/2020/8921892

[157] Development and validation of a questionnaire assessing discrepancy between patients’ pre‐surgery expectations and abilities and post‐surgical outcomes following knee replacement surgery. Knee Surgery, Sports Traumatology, Arthroscopy. 2014. DOI: 10.1007/s00167-014-3432-4

[159] “Doc, I Just Want My Life Back…”: Total Knee Arthroplasty and Its Effects on Chronic Bodily Pain. Journal of Bone and Joint Surgery. 2023. DOI: 10.2106/jbjs.23.00839

[160] Patient Expectations Regarding Total Knee Arthroplasty. The Journal of Bone & Joint Surgery. 2006. DOI: 10.2106/jbjs.e.00147

[161] Do_surgical_patellar_interventions_restore_patellar_kinematics_in_fixed-bearing,_S0883540314004744. The Journal of Arthroplasty. 2014. DOI: 10.1016/j.arth.2014.07.008

[164] The WOMAC score can be reliably used to classify patient satisfaction after total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-4879-5

[165] Bilateral total knee replacement under a single anaesthetic, using a cementless implant is not unsafe. Knee Surgery, Sports Traumatology, Arthroscopy. 2006. DOI: 10.1007/s00167-006-0196-5

[166] The reason why orthopaedic surgeons perform total knee replacement: results of a randomised study using case vignettes. Knee Surgery, Sports Traumatology, Arthroscopy. 2016. DOI: 10.1007/s00167-015-3961-5

[167] Clinical Outcome and Complications After Kinematic Total Knee Arthroplasty and After Kinemax Total Knee Arthroplasty. 1999.

[168] Risk factors for general complications after hip or knee replacement surgery in elderly patients: a single-center study. BMC Musculoskeletal Disorders. 2025. DOI: 10.1186/s12891-025-08742-5

[170] Cost and Effectiveness of Routine Pathological Examination of Operative Specimens Obtained During Primary Total Hip and Knee Replacement in Patients with Osteoarthritis. The Journal of Bone and Joint Surgery-American Volume*. 2000. DOI: 10.2106/00004623-200011000-00002

[171] The estimated lifetime risk of revision after primary knee arthroplasty is influenced by age, sex, and indication. The Bone & Joint Journal. 2022. DOI: 10.1302/0301-620x.104b12.bjj-2021-1631.r3

[172] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > TOTAL KNEE ARTHROPLASTY ALIGNMENT TECHNIQUES.

[174] AAOS Appropriate Use Criteria: Surgical Management of Osteoarthritis of the Knee. Journal of the American Academy of Orthopaedic Surgeons. 2018. DOI: 10.5435/jaaos-d-17-00425

[175] Emergency Department Visits Following Elective Total Hip and Knee Replacement Surgery: Identifying Gaps in Continuity of Care. Journal of Bone and Joint Surgery. 2017. DOI: 10.2106/jbjs.16.00692

[176] Improvements in functional outcome and quality of life are not sustainable for patients ≥ 68 years old 10 years after total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-06200-4

[177] Causes of Instability After Total Knee Arthroplasty. The Journal of Arthroplasty. 2014. DOI: 10.1016/j.arth.2013.06.023

[178] Both younger and elderly patients in pain are willing to undergo knee replacement despite the COVID‐19 pandemic: a study on surgical waiting lists. Knee Surgery, Sports Traumatology, Arthroscopy. 2021. DOI: 10.1007/s00167-021-06611-x

[179] Comparison of Time and Rate of Achieving Minimal Clinically Important Difference: Robotic Versus Manual Unicompartmental Knee Arthroplasty. Journal of the American Academy of Orthopaedic Surgeons. 2024. DOI: 10.5435/jaaos-d-24-00380

[181] Licensed and Liable. Insurance, Road Regulations, and Driving After Hip and Knee Arthroplasty Surgery. The Journal of Arthroplasty. 2023. DOI: 10.1016/j.arth.2022.10.024

[182] Classifications of good versus poor outcome following knee arthroplasty should not be defined using arbitrary criteria. BMC Musculoskeletal Disorders. 2020. DOI: 10.1186/s12891-020-03583-w

[183] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > BIOMECHANICS.

[185] Range of motion after total knee arthroplasty: the effect of a preoperative home exercise program. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-2349-z

[192] Response Shift in Outcome Assessment in Patients Undergoing Total Knee Arthroplasty. The Journal of Bone & Joint Surgery. 2006. DOI: 10.2106/jbjs.f.00283

[193] Physical activity after outpatient surgery and enhanced recovery for total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2016. DOI: 10.1007/s00167-016-4256-1

[196] Mismatched knee implants in Indonesian and Dutch patients: a need for increasing the size. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-05914-9

[199] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > MENISCAL INJURIES.

[200] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > COMPLICATIONS.

[202] Aaos Comprehensive Orthopaedic Review 3. Revision Total Knee Arthroplasty > I. Causes of Implant Failure.

[204] Total Knee Replacement Plus Nonsurgical Treatment Was Better Than Nonsurgical Treatment Alone for Knee Osteoarthritis. Journal of Bone and Joint Surgery. 2016. DOI: 10.2106/jbjs.16.00208

[205] Miller S Review Of Orthopaedics. SECTION 16 PATELLAR TRACKING IN TOTAL KNEE ARTHROPLASTY > COMPLICATIONS > 15. Osteolysis.

[206] Joint Line Obliquity Affects Survivorship Following Total Knee Arthroplasty: 12.7-Year Follow-Up of 800 Cases. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2025.10.114

[207] Letter Regarding “Prehabilitation in Patients at Risk of Poorer Outcomes Following Total Knee Arthroplasty: A Systematic Review.”. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2024.12.021

[209] Return to Duty and Deployment After Major Joint Arthroplasty. The Journal of Arthroplasty. 2013. DOI: 10.1016/j.arth.2013.02.028

[210] Light intensity physical activity increases and sedentary behavior decreases following total knee arthroplasty in patients with osteoarthritis. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-4987-2

[211] Similar survival between uncemented and cemented fixation prostheses in total knee arthroplasty: a meta‐analysis and systematic comparative analysis using registers. Knee Surgery, Sports Traumatology, Arthroscopy. 2013. DOI: 10.1007/s00167-013-2806-3

[212] Outcomes at 20 Years After Meniscectomy in Patients Aged 50 to 70 Years. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2021. DOI: 10.1016/j.arthro.2020.11.053

[213] Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty. American Academy of Orthopaedic Surgeon. 2011.

[214] Larger range of motion and increased return to activity, but higher revision rates following unicompartmental versus total knee arthroplasty in patients under 65: a systematic review. Knee Surgery, Sports Traumatology, Arthroscopy. 2017. DOI: 10.1007/s00167-017-4817-y

[215] Personalised medicine in knee arthroplasty: we need more science!. Knee Surgery, Sports Traumatology, Arthroscopy. 2019. DOI: 10.1007/s00167-019-05428-z

[216] Improving the Reliability of a Novel Baldini Classification for Revision Total Knee Arthroplasty: The Development and Validation of the Modified Grading System. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.06.061

[217] Expectation, satisfaction and clinical outcome of patients after total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2011. DOI: 10.1007/s00167-011-1621-y

[220] Anatomical site of radiographic degeneration is an independent variable influencing outcome of total knee arthroplasty. Journal of ISAKOS. 2024. DOI: 10.1016/j.jisako.2024.01.002

[223] Comparison of Mini-Midvastus and Conventional Total Knee Arthroplasty with Clinical and Radiographic Evaluation. Journal of Bone and Joint Surgery. 2016. DOI: 10.2106/jbjs.15.00654

[224] The Unified Classification System (UCS): improving our understanding of periprosthetic fractures. The Bone & Joint Journal. 2014. DOI: 10.1302/0301-620x.96b6.34040

[225] The incidence of implant fractures after knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2016. DOI: 10.1007/s00167-016-4160-8

[226] Comparison of simultaneous bilateral versus unilateral total knee replacement on pain levels and functional recovery. BMC Musculoskeletal Disorders. 2020. DOI: 10.1186/s12891-020-03269-3

[227] Improved early outcome after TKA through an app-based active muscle training programme—a randomized-controlled trial. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-4918-2

[231] Is Prescribed Postoperative Physical Therapy Necessary after Routine Primary Total Knee or Total Hip Arthroplasty?. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2024.10.105

[233] Changes in knee outcome measures following later-stage exercise interventions implemented ≤ 12 weeks vs. > 12 weeks after total knee arthroplasty: a systematic review and meta-analysis. Journal of Orthopaedic Surgery and Research. 2025. DOI: 10.1186/s13018-025-06430-7

[234] Visible fluid motion on manipulation as the new threshold for intraoperatively determined knee arthroplasty component loosening: A Delphi study. Knee Surgery, Sports Traumatology, Arthroscopy. 2024. DOI: 10.1002/ksa.12357

[236] Patient‐reported outcome after fast‐track knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-1919-4

[237] Hinged total knee arthroplasty.. The Journal of Bone & Joint Surgery. 1980. DOI: 10.2106/00004623-198062040-00004

[242] Generic implant classification enables comparison across implant designs: the Dutch Arthroplasty Register implant library. EFORT Open Reviews. 2019. DOI: 10.1302/2058-5241.4.180063

[245] Uncemented or cemented femoral components work equally well in total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2018. DOI: 10.1007/s00167-018-5227-5

[246] MRI and SPECT/CT demonstrate, with low certainty of evidence, the highest diagnostic accuracy for aseptic knee arthroplasty loosening: A systematic comparative diagnostic test review and meta‐analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2024. DOI: 10.1002/ksa.12206

[248] Activity levels and return to work following total knee arthroplasty in patients under 65 years of age. The Bone & Joint Journal. 2017. DOI: 10.1302/0301-620x.99b8.bjj-2016-1364.r1

[249] Full-Thickness Cartilage Defects Are Important Independent Predictive Factors for Progression to Total Knee Arthroplasty in Older Adults with Minimal to Moderate Osteoarthritis. Journal of Bone and Joint Surgery. 2019. DOI: 10.2106/jbjs.17.01657

[251] Recovery in knee range of motion reaches a plateau by 12 months after total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2014. DOI: 10.1007/s00167-014-3212-1

[252] Total knee arthroplasty post-high tibial osteotomy, results of an early experience from a North African arthroplasty unit, and a comprehensive review of the literature. Journal of Orthopaedic Surgery and Research. 2023. DOI: 10.1186/s13018-023-04199-1

[259] Twenty‐one sports activities are recommended by the European Knee Associates (EKA) six months after total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2021. DOI: 10.1007/s00167-020-06400-y

[260] Knee OA cost comparison for hyaluronic acid and knee arthroplasty. Journal of Orthopaedic Surgery and Research. 2020. DOI: 10.1186/s13018-020-01848-7

[261] Better clinical outcomes and overall higher survival with hybrid versus cemented primary total knee arthroplasty: a minimum 15 years follow‐up. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-06028-y

[268] Contemporary Mortality Rate and Outcomes in Nonagenarians After Primary Total Knee Arthroplasty. The Journal of Arthroplasty. 2021. DOI: 10.1016/j.arth.2021.05.015

[269] When is it safe to resume driving after total hip and total knee arthroplasty?. The Bone & Joint Journal. 2017. DOI: 10.1302/0301-620x.99b5.bjj-2016-1064.r1

[270] A comprehensive comparison between cementless and cemented fixation in the total knee arthroplasty: an updated systematic review and meta-analysis. Journal of Orthopaedic Surgery and Research. 2021. DOI: 10.1186/s13018-021-02299-4

[272] No difference between mobile and fixed bearing in primary total knee arthroplasty: a meta‐analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2022. DOI: 10.1007/s00167-022-07065-5

[273] Extensor Mechanism Failure Associated With Total Knee Arthroplasty: Prevention and Management. Journal of the American Academy of Orthopaedic Surgeons. 2003. DOI: 10.5435/00124635-200307000-00003

[274] Total_Knee_Arthroplasty_and_the_Unforeseen_Impact_on_Return_to_Work_A_Cross-Sect_S0883540314000084. The Journal of Arthroplasty. 2014. DOI: 10.1016/j.arth.2014.01.004

[275] Can Same-Day Total Joint Arthroplasty Be An Everyday Surgery for Everyone? An Editorial Viewpoint. The Journal of Arthroplasty. 2024. DOI: 10.1016/j.arth.2023.11.018

[278] Mild radiographic osteoarthritis is associated with increased pain and dissatisfaction following total knee arthroplasty when compared with severe osteoarthritis: a systematic review and meta‐analysis. Knee Surgery, Sports Traumatology, Arthroscopy. 2021. DOI: 10.1007/s00167-021-06487-x

[279] Patient-reported outcomes following cemented versus cementless primary total knee arthroplasty: a comparative analysis based on propensity score matching. BMC Musculoskeletal Disorders. 2022. DOI: 10.1186/s12891-022-05899-1

[281] Aaos Comprehensive Orthopaedic Review 3. Revision Total Knee Arthroplasty > II. Evaluation of the Painful Total Knee Arthroplasty.

[284] Knee Arthrodesis After Failure of Knee Arthroplasty. Journal of Bone and Joint Surgery. 2016. DOI: 10.2106/jbjs.15.01363

[286] Use of natural language processing techniques to predict patient selection for total hip and knee arthroplasty from radiology reports. The Bone & Joint Journal. 2024. DOI: 10.1302/0301-620x.106b7.bjj-2024-0136

[291] Early revisions of the Femoro-Patella Vialla joint replacement. The Bone & Joint Journal. 2013. DOI: 10.1302/0301-620x.95b6.31355

[292] Diagnostic value of magnetic resonance imaging for patients with periprosthetic joint infection: a systematic review. BMC Musculoskeletal Disorders. 2023. DOI: 10.1186/s12891-023-06926-5

[293] Contemporary failure aetiologies of the primary, posterior-stabilised total knee arthroplasty. The Bone & Joint Journal. 2017. DOI: 10.1302/0301-620x.99b5.bjj-2016-0617.r3

[294] Early complications and causes of revision after rotating-hinge TKA. Archives of Orthopaedic and Trauma Surgery. 2019. DOI: 10.1007/s00402-019-03290-9

[296] Risk factors for joint replacement in knee osteoarthritis; a 15-year follow-up study. BMC Musculoskeletal Disorders. 2017. DOI: 10.1186/s12891-017-1871-z

[297] Success_of_Different_Knee_Arthrodesis_Techniques_After_Failed_Total_Knee_Arthrop_S0883540313007742. The Journal of Arthroplasty. 2014. DOI: 10.1016/j.arth.2013.09.054

[301] Projections and Epidemiology of Revision Hip and Knee Arthroplasty in the United States to 2030. The Journal of Arthroplasty. 2020. DOI: 10.1016/j.arth.2020.02.030

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[303] Clinical value of SPECT/CT in the ‘unhappy’ total knee arthroplasty (TKA)- a prospective study in a consecutive series of 100 painful knees after TKA. Orthopaedic Journal of Sports Medicine. 2016. DOI: 10.1177/2325967116s00051

[307] Revision Total Knee Arthroplasty With Modular Cemented Stems. The Journal of Arthroplasty. 2007. DOI: 10.1016/j.arth.2007.03.025

[312] Decreased infection rates following total joint arthroplasty in a large county run teaching hospital: A single surgeon's experience and possible solution. The Journal of Arthroplasty. 2014. DOI: 10.1016/j.arth.2014.03.012

[313] A Systematic Review of Total Knee Arthroplasty in Neurologic Conditions: Survivorship, Complications, and Surgical Considerations. The Journal of Arthroplasty. 2020. DOI: 10.1016/j.arth.2020.08.008

[314] Symptomatic Osteonecrosis of the Hip and Knee After Cardiac Transplantation. The Journal of Arthroplasty. 2008. DOI: 10.1016/j.arth.2007.01.006

[315] The Ugly Underbelly of the MIS Movement. The Journal of Arthroplasty. 2007. DOI: 10.1016/j.arth.2006.12.055

[316] Heterotopic Ossification After Hip and Knee Arthroplasty: Risk Factors, Prevention, and Treatment. Journal of the American Academy of Orthopaedic Surgeons. 2002. DOI: 10.5435/00124635-200211000-00005

[317] Prevalence and Impact of Unexpected Positive Intraoperative Cultures in Total Hip or Knee Revision Surgery. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2024.07.031

[318] Why Do Revision Knee Arthroplasties Fail?. The Journal of Arthroplasty. 2008. DOI: 10.1016/j.arth.2008.04.020

[320] Total Knee and Hip Arthroplasty in Patients Who Had Prior Septic Arthritis: A Systematic Review and Meta-Analysis. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2026.06.056

[321] Analysis of Oxford medial unicompartmental knee replacement using the minimally invasive technique in patients aged 60 and above: an independent prospective series. Knee Surgery, Sports Traumatology, Arthroscopy. 2007. DOI: 10.1007/s00167-007-0397-6

[322] Evolving etiologies and rates of revision total knee arthroplasty: a 10-year institutional report. Arthroplasty. 2022. DOI: 10.1186/s42836-022-00134-7

[323] A “biologic technique” for the treatment of a disruption of the extensor mechanism after revision total knee arthroplasty: a case report. Knee Surgery, Sports Traumatology, Arthroscopy. 2008. DOI: 10.1007/s00167-008-0533-y

[324] Double-layered patella management in total knee arthroplasty for secondary osteoarthritis: A case report. Journal of ISAKOS. 2022. DOI: 10.1016/j.jisako.2022.01.004

[326] Detection_of_Small_Periprosthetic_Bone_Defects_after_Total_Knee_Arthroplasty_S0883540314003295. The Journal of Arthroplasty. 2014. DOI: 10.1016/j.arth.2014.05.013

[327] Routine Radiographs After Total Joint Arthroplasty: Is There Clinical Value?. The Journal of Arthroplasty. 2021. DOI: 10.1016/j.arth.2021.02.050

[328] Femoral component rotational alignment in robotic‐assisted total knee arthroplasty with functional knee positioning varies across knee phenotypes without affecting clinical outcomes. Knee Surgery, Sports Traumatology, Arthroscopy. 2025. DOI: 10.1002/ksa.12732

[330] Severe arthritis predicts greater improvements in function following total knee arthroplasty. Knee Surgery, Sports Traumatology, Arthroscopy. 2015. DOI: 10.1007/s00167-015-3806-2

[332] Re-admissions, re-operations and length of stay in hospital after aseptic revision knee replacement in Denmark. The Bone & Joint Journal. 2014. DOI: 10.1302/0301-620x.96b12.33621

[333] Artificial Intelligence to Identify Arthroplasty Implants From Radiographs of the Knee. The Journal of Arthroplasty. 2021. DOI: 10.1016/j.arth.2020.10.021

[334] Primary_Repair_of_Iatrogenic_Medial_Collateral_Ligament_Injury_During_TKA_A_Modi_S0883540315000030. The Journal of Arthroplasty. 2015. DOI: 10.1016/j.arth.2014.12.020

[336] Does Unicondylar Knee Arthroplasty Failure Mode Impact Conversion Total Knee Arthroplasty Outcomes?. The Journal of Arthroplasty. 2026. DOI: 10.1016/j.arth.2025.06.041

[337] Isolated Versus Full Component Revision in Total Knee Arthroplasty for Aseptic Loosening. The Journal of Arthroplasty. 2023. DOI: 10.1016/j.arth.2022.09.006

[339] Low grading of the severity of knee osteoarthritis pre-operatively is associated with a lower functional level after total knee replacement. The Bone & Joint Journal. 2014. DOI: 10.1302/0301-620x.96b11.33726

[340] TKA outcomes after prior bone and soft tissue knee surgery. Knee Surgery, Sports Traumatology, Arthroscopy. 2012. DOI: 10.1007/s00167-012-2139-7

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