Implants & Hardware¶
Spinal fixation and reconstruction hardware: material selection (Titanium, PEEK, Cobalt-Chrome), design considerations, and failure modes.
Overview¶
Silicone metacarpophalangeal arthroplasty demonstrates high clinical survivorship of 97% in long-term follow-up, though radiographic survivorship is lower at 88% [1]. In the realm of intervertebral disc prostheses, both keel and spike anchoring concepts for the Activ L® device fulfill the required criteria for primary stability [24]. For reverse total shoulder arthroplasty in patients with severe glenoid bone loss, osteoarthritis, and an intact rotator cuff, reaming the glenoid flat without bone-grafting yields excellent prosthetic survival with clinical results maintained at a minimum 5-year follow-up [44].
The EFORT Implant and Patient Safety Initiative has established recommendations to address pre-clinical and clinical requirements for new implants, emphasizing a phased introduction to identify failures and ensure patient safety before routine market use [27]. While the routine insertion of RSA beads is a safe procedure that may allow for the assessment of implant fixation in clinical practice [16], significant data gaps remain. There is an urgent need for large randomized trials regarding implant removal efficacy and patient-centred outcomes [9], as well as longer follow-up and prospective comparisons to better define revision, failure, and complication rates for proximal interphalangeal joint prosthetic arthroplasty [14].
Surgeons must carefully weigh the paucity of definitive long-term data regarding bioabsorbable interbody spacers against their potential benefits [41]. For basicervical femoral neck fractures, biomechanical analysis has not determined the superiority of one fixation device over others; consequently, constructs should be selected based on individual patient anatomy and the surgeon's comfort with the implant [4]. Specific procedural considerations include leaving difficult-to-remove cement or hardware during 2-stage revision shoulder arthroplasty for infection to avoid increased morbidity [2], and maintaining careful follow-up for patients with magnetically controlled growing rods due to metallosis risk [3].
Anatomy & Pathophysiology¶
Kinematics and Motion Patterns¶
Total disc replacements demonstrate durability with no mechanical failures observed after 30-million-cycle intervals simulating approximately 80 years of lumbar-bending motions [28]. In CHARITÉ discs implanted in human cadaveric lumbar spines and patients, preferentially larger motion occurs at the superior bearing regardless of the implanted level [31]. For cervical arthroplasty, only prosthesis with flexible biomechanical properties should be used to achieve a near-physiological motion pattern [49]. The biomechanical concept significantly impacts this outcome, as flexible properties shift the center of rotation toward normal, whereas fixed ball socket designs potentially worsen the motion pattern [49]. Authors of a small-sample RCT expect to draw conclusions regarding fusion and motion patterns in cervical spine kinematics after anterior cervical discectomy with or without mobile cervical disc prosthesis implantation [32].
Osseous Fixation and Stability¶
Pedicle Screw Orientation: In the sagittal position, L1 and L2 pedicle screws should be placed as parallel to the endplate as possible to obtain the best pull-out resistance [36]. Conversely, L3, L4, and L5 pedicle screws should be placed as appropriate as possible to the tail tilt theoretically to obtain optimal pull-out resistance [36]. In healthy vertebrae, both conical and dual-core/dual-thread screw designs improve pullout strength, with a combination achieving optimal stability [42]. Boron-coated titanium alloy pedicle screws demonstrate stronger biomechanical properties in a rabbit spine model, suggesting they could be a better alternative to currently used titanium screws [33].
Baseplate and Stem Micromotion: Baseplate micromotion negatively correlates with compression, with higher compressive forces significantly reducing micromotion in reverse shoulder arthroplasty baseplate design [34]. In reverse shoulder arthroplasty, baseplate stress and displacement are lower with a smaller glenosphere, inferior tilt, and divergent screws [51]. Most surgical aspects of baseplate fixation in reverse total shoulder arthroplasty for patients without glenoid bone loss can be decided without affecting fixation strength, and there is not a single strategy that provides the best outcome [47]. In cementless total hip arthroplasty short stem designs, micromotion was greater at the proximal and distal ends in finite element analysis models [56]. The direction of micromotion in these short stem designs is not dependent on stem shape but on the direction of the load [56].
Cage and Joint Stability: Higher magnitudes of cage subsidence are associated with worse clinical improvements and lower intervertebral fusion following oblique lumbar interbody fusion combined with anterolateral fixation [38]. Robotic-assisted burr preparation significantly improves cement penetration in total knee arthroplasty but does not translate to improved immediate fixation strength in time-zero biomechanical testing [39]. Increased taper angle and broad spline geometry exhibited significantly greater axial stability (21%–269% increase) compared to other design combinations in implant stability studies [53]. Neither taper angle nor spline geometry significantly altered initial torsional stability in implant stability studies [53].
Spinopelvic and Complex Fixation¶
Spinopelvic fixation is a powerful technique to resist flexion and cantilever forces that contribute to pseudarthrosis, though it is associated with high complication rates [46]. Computer simulation results regarding patient-specific optimization of locking plates for proximal humerus fracture fixation require biomechanical and clinical corroboration [37]. A novel proximal interphalangeal joint implant design using a rolling contact joint mechanism demonstrated acceptable outcomes in terms of human kinematics and tendon excursions [57]. The measurement error for model-based Roentgen Stereophotogrammetric Analysis is good for translations but high for rotations when evaluating early migration of the trapeziometacarpal joint prosthesis [52].
Classification¶
Implant Survivorship & Failure Modes: Silicone metacarpophalangeal arthroplasty implants demonstrate 97% clinical and 88% radiographic survivorship in long-term follow-up [1]. Conversely, the RM finger prosthesis system exhibited unacceptable failure rates, requiring revision of 15 implants by 2 years [7]. In the basal thumb joint, prosthesis loosening was not detected in cemented surface replacement prostheses [8]. Early loosening of uncemented, custom-made, hydroxyapatite-coated collared distal femoral endoprostheses indicates that initial fixation is crucial [6]. For proximal femur metastases, endoprostheses and intramedullary devices show comparable functional scores and implant survivorship that exceeds patient survivorship [12].
Fixation & Application Safety: No single fixation construct for basicervical femoral neck fractures demonstrates superiority over others [4]. The major reason for failure of surgical implants is faulty application of the device where the margin of safety is exceeded [43]. Both keel and spike anchoring concepts for the Activ L® intervertebral disc prosthesis fulfill the required criteria of primary stability [24]. Routine use of radiostereometric analysis (RSA) bead insertion is a safe procedure that may provide the ability to assess implant fixation in clinical practice [16].
Infection, Revision & Material Selection: Retained cement or hardware during 2-stage revision shoulder arthroplasty for infection may be left if removal leads to increased morbidity and future complications [2]. There is no consensus that specific implant materials mitigate the risk for surgical site infections or periprosthetic joint infections [11]. Technologic advances in implant materials, design, amputee care, and imaging continue to drive improvements in patient care and outcomes [13].
Pediatric & Regulatory Considerations: Instrumentation failure, including anchor-related complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries for pediatric spine deformity [10]. The EFORT Implant and Patient Safety Initiative developed recommendations emphasizing a phased introduction of new implants to identify failures and ensure patient safety before routine market use [27].
Clinical Presentation¶
Long-term follow-up of silicone metacarpophalangeal arthroplasty implants demonstrates 97% clinical survivorship and 88% radiographic survivorship [1]. In contrast, the RM finger prosthesis joint replacement system exhibited unacceptable failure rates, with 15 implants revised by 2 years [7]. Poly-L/D-lactide scaffolds used for thumb trapeziometacarpal arthroplasty are associated with a high frequency of osteolysis around the implant and foreign-body reactions in seven patients [5]. Uncemented distal femoral endoprostheses exhibit early loosening, indicating that initial fixation is crucial [6]. Surrounding bone does not form a stable interface with pyrolytic carbon implants, as suggested by clinical outcomes and radiographic signs of loosening [18]. Conversely, prosthesis loosening was not detected in cemented surface replacement prostheses used in the basal thumb joint [8].
Forearm pain associated with loose radial head prostheses is considered diagnostic even in the absence of radiographic signs if the prosthesis has a textured surface for bone ingrowth and was inserted without cement [19]. Early diagnosis of polyethylene liner fracture in dual mobility trapeziometacarpal total joint replacement allows revision surgery with exchange of the neck and polyethylene head without revising a well-fixed cup [20]. Instrumentation failure, including anchor-related complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries for pediatric spine deformity [10]. Patients receiving magnetically controlled growing rods require careful follow-up due to the risk of metallosis [3]. Foreign body-type cells and adverse outcomes are potential risks after the use of Artelon implants [30].
Regarding implant selection and material properties, no single fixation construct for basicervical femoral neck fractures demonstrates superiority; selection should be based on individual patient anatomy and surgeon comfort [4]. Endoprostheses and intramedullary devices for proximal femur metastases show comparable functional scores and implant survivorship exceeding patient survivorship [12]. Technologic advances in implant materials, design, amputee care, and imaging continue to drive improvements in patient care and outcomes [13]. There is no consensus that specific implant materials mitigate the risk for surgical site infections or periprosthetic joint infections [11]. Metal sensitivity to implants may exist as an extreme complication in only a few highly predisposed people and may also be a subtle contributor to implant failure [29]. Retained cement or hardware during 2-stage revision shoulder arthroplasty for infection may be left if removal leads to increased morbidity and future complications [2].
Investigations¶
Plain radiography: Radiographs are useful to screen for clinically significant osteolysis, with sensitivity increasing to 92.8% for lesions larger than 1000 mm3 [63]. In the context of periprosthetic fractures around uncemented femoral components, the addition of preoperative CT did not significantly improve accuracy in predicting fixation status compared with plain radiography [50]. Radiographic loosening of uncemented, custom-made, hydroxyapatite-coated collared distal femoral endoprostheses occurs early, indicating that initial fixation is crucial [6]. Conversely, prosthesis loosening was not detected in a cemented surface replacement prosthesis in the basal thumb joint [8]. Various imaging changes occur after Coflex implantation, most of which do not affect clinical outcomes [62]. Spherical ceramic trapezial-metacarpal arthroplasty is no longer used by the authors based on medium-term radiographic outcomes [15]. Surrounding bone does not form a stable interface with pyrolytic carbon implants, as suggested by clinical outcomes and radiographic signs of loosening [18]. Many patients with the iBP elbow prosthesis have radiolucencies, and the discrepancy between clinical signs and radiological results warrants structural follow-up [59]. Silicone metacarpophalangeal arthroplasty implant survivorship is 97% clinically and 88% radiographically in long-term follow-up [1].
MRI: Magnetic resonance imaging indicates that the donor site after autologous osteochondral mosaicplasty for cartilaginous lesions of the elbow joint is resurfaced with fibrous tissue [55].
CT: CT-based Implant Motion Analysis is recommended for the investigation and diagnosis of patients with megaprostheses with symptoms suggestive of loosening and for preoperative planning of revision surgery [45].
Other Considerations: Careful follow-up is recommended for patients who have received magnetically controlled growing rods due to the risk of metallosis [3]. Forearm pain associated with loose radial head prostheses is considered diagnostic even in the absence of radiographic signs if the prosthesis has a textured surface for bone ingrowth and was inserted without cement [19]. Early diagnosis of polyethylene liner fracture in dual mobility trapeziometacarpal total joint replacement allows revision surgery with exchange of the neck and polyethylene head without revising a well-fixed cup [20]. Poly-L/D-lactide scaffolds for thumb trapeziometacarpal arthroplasty are associated with a high frequency of osteolysis around the implant and clinically manifested foreign-body reactions in seven patients [5]. The Trabecular Metal Monoblock Acetabular Cup System showed excellent early clinical and radiographic behavior [64]. Two-level anterior cervical discectomy and fusion using either allografts or Polyetheretherketone (PEEK) cages resulted in similar clinical outcomes, radiological improvements in alignment, and fusion rates [65]. No single fixation construct for basicervical femoral neck fractures demonstrates superiority; selection should be based on individual patient anatomy and surgeon comfort [4]. Surgeons should consider leaving cement or hardware that is difficult to remove during 2-stage revision shoulder arthroplasty for infection to avoid increased morbidity and future complications [2]. Technologic advances in implant materials, design, amputee care, and imaging continue to drive improvements in patient care and outcomes [13].
Treatment¶
Operative¶
Implant Selection: Silicone metacarpophalangeal arthroplasty for osteoarthritis demonstrates 97% clinical implant survivorship but only 88% radiographic implant survivorship in long-term follow-up [1]. The RM finger prosthesis joint replacement system exhibited unacceptable failure rates at early and medium term stages, with 15 implants revised by 2 years [7]. For thumb trapeziometacarpal arthroplasty, a poly-L/D-lactide scaffold is associated with a high frequency of osteolysis and clinically manifested foreign-body reactions in seven patients, though it provided pain relief and improved overall function in most patients [5]. In the hip, no revisions occurred during follow-up for the large-diameter Delta Motion ceramic total hip bearing [17]. For the radial head, a well-fixed MoPyc radial head arthroplasty provides satisfactory short to midterm outcomes without painful loosening [35]. Total elbow arthroplasty demonstrates acceptable implant survival rates at 5 and 10 years, yet the unlinked design carries a higher revision rate due to fracture sequelae [22]. In lower-limb endoprosthetic reconstructions, the use of a fully porous bridging collar may translate to a reduced incidence of aseptic loosening in the medium term [61]. For proximal femur metastases, endoprostheses and intramedullary devices demonstrate comparable functional scores, and implant survivorship exceeds patient survivorship [12].
Indications: TACTYS arthroplasty can be proposed for patients who have been treated long enough with unsuccessful conservative treatment [54]. Patients who have received magnetically controlled growing rods require careful follow-up due to the risk of metallosis [3]. Osseointegration is critical for the long-term outcome of three-dimensional-printed custom-made hemipelvic endoprostheses for primary malignancies involving the acetabulum [25].
Surgical Approach / Technique: Surgeons should consider leaving cement or hardware that is difficult to remove during 2-stage revision shoulder arthroplasty for infection to avoid increased morbidity and future complications [2]. For basicervical femoral neck fractures, no single fixation construct has been determined to be superior to others; surgeons should select fixation constructs based on individual patient anatomy and surgeon comfort with the implant [4]. There is no difference in revision rate, nonunion rate, or the prevalence of painful implant between locking and nonlocking dorsal plate fixation constructs for primary first MTP arthrodesis [48].
Adjuncts: Routine use of radiostereometric analysis (RSA) bead insertion is a safe procedure and may provide the ability to assess implant fixation in clinical practice [16]. Initial implant stability is an important factor contributing to ultimate stable fixation by extracortical bone formation, as is the application of sufficient autogenous bone grafts [26]. Three design elements are required for osseointegration in three-dimensional-printed custom-made hemipelvic endoprostheses: interface connection, porous structure, and initial stability achieved by precise matching and proper fixation methods [25].
Other Considerations: There is no consensus that specific implant materials mitigate the risk for surgical site infections or periprosthetic joint infections [11]. There is an urgent need for a large randomized trial to determine the efficacy and effectiveness of orthopaedic implant removal regarding patient-centred outcomes [9].
Complications¶
Aseptic loosening: Loosening of uncemented, custom-made, hydroxyapatite-coated collared distal femoral endoprostheses occurs early, making initial fixation crucial to prevent this complication [6]. Poly-L/D-lactide scaffolds for thumb trapeziometacarpal arthroplasty are associated with a high frequency of osteolysis around the implant [5]. The spherical ceramic trapezial-metacarpal arthroplasty implant is no longer used by the authors based on radiographic outcomes at medium-term follow-up [15]. Silicone metacarpophalangeal arthroplasty implants demonstrate 88% radiographic survivorship in long-term follow-up [1].
Implant failure and wear: Widespread and poorly monitored adoption of metal-on-metal hip prostheses resulted in enormous excess failure with over 1 million implants worldwide [60]. Metallosis can occur following implantation of magnetically controlled growing rods in the treatment of scoliosis [3]. The RM finger prosthesis joint replacement system exhibited unacceptable failure rates at early and medium term stages, with 15 implants revised by 2 years [7]. Bipolar radial head arthroplasty is associated with major primary complications and a high incidence of radiographic signs of degenerative changes after 8.8 years [58]. Long-term implant failure could not be predicted by 2-year migration results in instrumented bone-preserving total elbow arthroplasty [21].
Foreign-body reaction: Seven patients developed clinically manifested foreign-body reactions following poly-L/D-lactide scaffold implantation for thumb trapeziometacarpal arthroplasty [5].
Other Considerations: Retained cement or hardware during 2-stage revision shoulder arthroplasty for infection may lead to increased morbidity and future complications if removal is difficult [2]. Instrumentation failure, including anchor-related complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries for pediatric spine deformity [10]. The revision rate for unlinked total elbow arthroplasty designs is higher than linked designs, with primary revisions occurring due to fracture sequelae [22]. Total elbow arthroplasty has acceptable implant survival rates after 5 and 10 years [22]. There were no revisions during follow-up for the large-diameter Delta Motion ceramic total hip bearing despite noise generation [17]. Titanium coating on polyetheretherketone oblique cages for transforaminal lumbar interbody fusion appears to have no negative effects on outcome or safety in the short term [23]. Silicone metacarpophalangeal arthroplasty implant survivorship is 97% clinically in long-term follow-up [1]. Longer follow-up and prospective randomized comparisons are needed to better define rates of revision, failure, and complications for proximal interphalangeal joint prosthetic arthroplasty [14]. Despite major primary complications and radiographic degenerative changes, bipolar radial head arthroplasty achieved mainly good clinical results [58].
Recovery¶
Light activity (weeks): Evidence does not specify a week range for light activity or driving.
Full activity (months): Evidence does not specify a month range for full activity or return to manual work.
Complete recovery / outcome plateau (months): Evidence does not specify a month range for outcome plateau or final functional stabilization.
Rehabilitation protocol: Evidence does not detail specific PT phasing, immobilization duration, or brace removal timing.
Functional milestones: Evidence does not report validated PROM trajectories or specific outcome-measure benchmarks.
Other Considerations: Long-term clinical survivorship of silicone metacarpophalangeal arthroplasty implants is 97%, while radiographic survivorship is 88% [1]. Careful follow-up is recommended for patients with magnetically controlled growing rods due to the risk of metallosis [3]. Poly-L/D-lactide scaffolds for thumb trapeziometacarpal arthroplasty demonstrated a high frequency of osteolysis around the implant on radiographs, and seven patients developed clinically manifested foreign-body reactions following their use [5]. Loosening of uncemented, custom-made, hydroxyapatite-coated collared distal femoral endoprostheses occurs early, making initial fixation crucial to prevent this complication [6]. The RM finger prosthesis joint replacement system exhibited unacceptable failure rates at early and medium term stages, with fifteen implants revised by 2 years [7]. Longer follow-up and prospective randomized comparisons are needed to better define rates of revision, failure, and complications for proximal interphalangeal joint prosthetic arthroplasty [14]. Authors no longer use spherical ceramic trapezial-metacarpal arthroplasty implants based on medium-term radiographic outcomes [15]. There were no revisions during follow-up for the large-diameter Delta Motion ceramic total hip bearing [17]. Long-term implant failure could not be predicted by 2-year migration results in instrumented bone preserving total elbow arthroplasty [21]. Titanium coating on polyetheretherketone oblique cages appears to have no negative effects on outcome or safety in the short term [23]. Osseointegration is critical for the long-term outcome of three-dimensional-printed custom-made hemipelvic endoprostheses, requiring three design elements: interface connection, porous structure, and initial stability achieved by precise matching and proper fixation methods [25]. Initial implant stability is an important factor contributing to ultimate stable fixation by extracortical bone formation, as is the application of sufficient autogenous bone grafts [26]. Long-term studies are necessary to evaluate the survivorship of pyrocarbon metacarpophalangeal joint replacement implants [40].
Key Evidence¶
- [L4] Implant survivorship is 97% (clinical) and 88% (radiographic) in long-term follow-up. (10.1016/j.jhsa.2017.10.010)
- [L3] Therefore, surgeons should consider leaving cement or hardware that is difficult to remove and may lead to increased morbidity and future complications. (10.1016/j.jse.2024.03.020)
- [L4] The authors recommend careful follow-up of patients who have received this implant. (10.1302/0301-620x.98b12.38061)
- [L5] The study could not determine superiority of one implant over the others and recommends that surgeons select fixation constructs based on the individual patient's anatomy and the surgeon's comfort with the implant. (10.5435/jaaos-d-17-00155)
- [L4] The procedure provided pain relief and improvement in overall function in most patients, but radiographs demonstrated a high frequency of osteolysis around the implant and seven patients developed clinically manifested foreign-body reactions. (10.1177/1753193415601952)
- [L3] Loosening of uncemented replacements occurs early indicating that initial fixation of the implant is crucial. (10.1302/0301-620x.96b2.32091)
- [L4] Unacceptable failure rates at early and medium term stages were identified, with 15 of the implants revised by 2 years. (10.1177/1753193411406798)
- [L4] Prosthesis loosening was not detected. (10.1016/j.jhsa.2009.12.026)
- [L4] Given the frequency of the procedure in orthopaedic departments worldwide, there is an urgent need for a large randomized trial to determine the efficacy and effectiveness of implant removal with regard to patient-centred outcomes. (10.1186/1471-2474-9-73)
- [L3] Instrumentation failure, such as anchor related-complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries. (10.1186/s12891-024-07211-9)
- [L5] There is no consensus that specific implant materials mitigate the risk for surgical site infections/periprosthetic joint infections, though a combination of approaches is likely needed. (10.1016/j.arth.2018.09.016)
- [L3] Patients may undergo stabilization with either approach with comparable functional scores and implant survivorship exceeding patient survivorship. (10.1007/s11999-011-2038-0)
- [L4] Longer follow-up and prospective randomized comparisons are needed to better define rates of revision, failure, and complications. (10.1016/j.jhsa.2010.04.005)
- [L4] Based on the radiographic outcome at this medium-term follow-up, the authors no longer use this implant. (10.1016/j.jhsa.2008.10.017)
- [L3] The routine use of RSA bead insertion is a safe procedure and may provide the ability to assess implant fixation in clinical practice. (10.5435/jaaos-d-17-00071)
- [L3] There were no revisions during follow-up. (10.1302/0301-620x.95b2.30450)
- [L5] The clinical outcomes and radiographic signs of loosening suggest that the surrounding bone does not form a stable interface with pyrolytic carbon implants. (10.2106/jbjs.k.00527)
- [L4] If the prosthesis has a textured surface for bone ingrowth and was inserted without cement, this symptom is considered diagnostic even in the absence of radiographic signs. (10.1016/j.jse.2011.05.008)
- [L4] Early diagnosis allows revision surgery with exchange of the neck and polyethylene head without revising a well-fixed cup. (10.1177/17531934241227918)
- [L4] Long-term implant failure could not be predicted by 2-year migration results in this study. (10.1016/j.jse.2019.07.023)
- [L3] We found acceptable implant survival rates after 5 and 10 years, with a higher revision rate for the unlinked design and primary TEA due to fracture sequelae. (10.1016/j.jse.2014.02.001)
- [L1] The titanium coating appears to have no negative effects on outcome or safety in the short term. (10.1302/0301-620x.99b10.bjj-2016-1292.r2)
- [L5] Both fixation systems fulfill the required criteria of primary stability. (10.1186/s12891-021-04544-7)
- [L4] Osseointegration is critical for long-term outcome and requires three design elements including interface connection, porous structure, and initial stability achieved by precise matching and proper fixation methods. (10.1186/s13018-019-1455-8)
- [L5] Initial implant stability and the application of sufficient autogenous bone grafts are two important factors that contribute to ultimate stable fixation by extracortical bone formation. (10.2106/00004623-198870020-00002)
- [L5] The EFORT Implant and Patient Safety Initiative developed recommendations to address pre-clinical and clinical requirements for new implants, emphasizing a phased introduction to identify failures and ensure patient safety before routine market use. (10.1530/eor-23-0072)
- [L5] No mechanical failures were observed, even after each 30-million-cycle interval, which simulates approximately 80 years of lumbar-bending motions. (10.2106/jbjs.25.00594)
- [Case_report] Metal sensitivity to implants may exist as an extreme complication in only a few highly predisposed people, but it may also be a subtle contributor to implant failure. (10.1007/s00167-012-2000-z)
- [L4] Patients and surgeons must be made aware of the potential for foreign body–type cells and an adverse outcome after use of the implant. (10.1016/j.jhsa.2010.10.001)
- [L5] We found preferentially larger motion at the superior bearing of the CHARITE´ discs implanted in human cadaveric lumbar spines and in patients, regardless of the implanted level. (10.2106/jbjs.j.00638)
- [L1] The authors note that while the sample size is small, they expect to draw conclusions about the primary outcome regarding fusion and motion patterns. (10.1186/s12891-015-0479-4)
- [L5] With stronger biomechanical properties, they could be a better alternative to currently used titanium screws. (10.1186/s12891-024-07864-6)
- [L5] Baseplate micromotion negatively correlates with compression, with higher compressive forces significantly reducing micromotion. (10.1016/j.jse.2023.07.043)
- [L4] A well-fixed MoPyc RHA provided satisfactory short to midterm outcomes, without painful loosening. (10.1016/j.jse.2024.06.018)
- [L4] Based on the analysis of statistical results, the placement direction of L1 and L2 in the sagittal position may be as parallel to the endplate as possible to obtain the best pull-out resistance; L3, L4, and L5 may be as appropriate as possible to the tail tilt theoretically. (10.1186/s12891-022-05074-6)
- [L5] These computer simulation results require biomechanical and clinical corroboration. (10.1016/j.jse.2021.06.012)
- [L3] Higher magnitudes of CS were associated with worse clinical improvements and lower intervertebral fusion. (10.1186/s12891-022-05165-4)
- [L5] However, this did not translate to improved immediate fixation strength in time‐zero biomechanical testing. (10.1002/ksa.12765)
- [L4] Long-term studies will be necessary to evaluate the survivorship of this new design of implant, particularly given some of the radiographic changes described in this article. (10.1177/1753193413511946)
- [L5] The paucity of definitive, long-term data must be carefully weighed against the potential benefits of these implants. (10.5435/00124635-200705000-00005)
- [L5] In healthy vertebrae, both conical and dual-core/dual-thread designs improve pullout strength, with a combination achieving optimal stability. (10.1371/journal.pone.0229328)
- [L5] The major reason for failure of implants is faulty application of the device, where the margin of safety is exceeded; cooperative investigation by surgeon, metallurgist, and pathologist is required to explain failures and prevent errors. (10.2106/00004623-196446020-00016)
- [L4] For the studied indication, reaming the glenoid flat produced excellent prosthetic survival with clinical results maintained at a minimum 5-year follow-up. (10.2106/jbjs.20.01042)
- [L4] The authors recommend the use of CT-based Implant Motion Analysis in the investigation and diagnosis of patients with a megaprosthesis with symptoms suggestive of loosening, and in the preoperative planning of revision surgery. (10.1302/0301-620x.107b5.bjj-2024-0517.r1)
- [L5] Spinopelvic fixation is a powerful technique to resist flexion and cantilever forces that contribute to pseudarthrosis, though it is associated with high complication rates. (10.5435/jaaos-d-15-00738)
- [L1] Most surgical aspects of baseplate fixation can be decided without affecting fixation strength, and there is not a single strategy that provides the best outcome. (10.5397/cise.2023.00493)
- [L3] There was no difference in revision rate, nonunion, or prevalence of painful implant between locking and nonlocking dorsal plate fixation for primary first MTP arthrodesis. (10.5435/jaaos-d-23-00185)
- [L4] The biomechanical concept of the prosthesis has a significant impact on whether a near-physiological motion pattern can be achieved, with flexible biomechanical properties shifting the center of rotation toward normal and fixed ball socket designs potentially worsening the motion pattern. (10.1186/s13018-020-01908-y)
- [L3] The addition of preoperative CT did not significantly improve accuracy in predicting fixation status compared with plain radiography. (10.1302/0301-620x.107b6.bjj-2024-0829.r1)
- [L5] Baseplate stress and displacement in an FEA model is lower with a smaller glenosphere, inferior tilt, and divergent screws. (10.1016/j.jse.2017.06.008)
- [L3] The measurement error is good for the translations but high for the rotations. (10.1186/s12891-015-0747-3)
- [L4] TACTYS arthroplasty can be proposed for people who have been treated long enough with unsuccessful conservative treatment. (10.1177/15589447211030962)
- [L4] However, magnetic resonance imaging indicates that the donor site is resurfaced with fibrous tissue. (10.1177/0363546507306465)
- [L5] In both models, the micromotion was greater at the proximal and distal ends, and the direction of micromotion was not dependent on stem shape but on the direction of the load. (10.1186/s13018-022-03329-5)
- [L5] A novel PIPJ implant design using an RCJ mechanism demonstrated acceptable outcomes in terms of PIPJ human kinematics and tendon excursions. (10.1186/s13018-019-1234-6)
- [L4] Despite major primary complications and high incidence of radiographic signs of degenerative changes after 8.8 years, mainly good clinical results were achieved with Judet's bipolar prosthesis. (10.1016/j.jse.2010.05.022)
- [L4] However, many patients have radiolucencies, and the discrepancy between clinical signs and radiological results warrants structural follow-up. (10.1186/s12891-019-2781-z)
- [L3] This study highlights the consequences of widespread and poorly monitored adoption of a medical technology, noting that over 1 million metal-on-metal hip prostheses were implanted worldwide with enormous excess failure. (10.2106/jbjs.17.00039)
- [L3] In the medium term, the use of a fully porous bridging collar may translate to a reduced incidence of aseptic loosening. (10.1186/s42836-023-00230-2)
- [L3] The study identified various imaging changes after Coflex implantation, most of which did not affect clinical outcomes. (10.1186/s12891-023-06798-9)
- [L3] Radiographs are useful to screen clinically significant osteolysis, with sensitivity increasing to 92.8% for lesions larger than 1000 mm3. (10.1016/j.arth.2008.02.012)
- [L4] The implant showed excellent early clinical and radiographic behavior. (10.1016/j.arth.2008.09.027)
- [L3] Two-level ACDF using either allografts or PEEK cages resulted in similar clinical outcomes, radiological improvements in alignment and fusion rates. (10.1186/s12891-020-03325-y)
See Also¶
References¶
[1] Silicone Metacarpophalangeal Arthroplasty for Osteoarthritis: Long-Term Results. The Journal of Hand Surgery. 2018. DOI: 10.1016/j.jhsa.2017.10.010
[2] Does retained cement or hardware during 2-stage revision shoulder arthroplasty for infection increase the risk of recurrent infection?. Journal of Shoulder and Elbow Surgery. 2025. DOI: 10.1016/j.jse.2024.03.020
[3] Metallosis following implantation of magnetically controlled growing rods in the treatment of scoliosis. The Bone & Joint Journal. 2016. DOI: 10.1302/0301-620x.98b12.38061
[4] Biomechanical Analysis of Fixation Devices for Basicervical Femoral Neck Fractures. Journal of the American Academy of Orthopaedic Surgeons. 2019. DOI: 10.5435/jaaos-d-17-00155
[5] Unfavourable short-term outcomes of a poly-L/D-lactide scaffold for thumb trapeziometacarpal arthroplasty. Journal of Hand Surgery (European Volume). 2015. DOI: 10.1177/1753193415601952
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