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Medial collateral ligament injury

71 citationsUpdated Sep 2026

Overview

Most isolated medial collateral ligament (MCL) injuries are managed nonsurgically [2]. However, concomitant damage to the anterior or posterior cruciate ligaments is a common indication for surgical management of high-grade MCL injuries [2]. Even in the presence of anterior cruciate ligament (ACL) injury, conservative treatment remains recommended for the initial management of acute MCL ruptures [4]. Nonoperative treatment for MCL injuries combined with ACL reconstruction provides clinical outcomes similar to those of isolated ACL reconstruction without MCL injury at 2-year follow-up [32]. The location of injury in the superficial layer may be useful in predicting the outcome of nonoperative treatment for acute grade III MCL lesions combined with ACL injury [3].

Surgical intervention is indicated for complex multiligament injuries. A one-stage protocol with early surgery rather than delayed reconstruction produced better clinical outcomes for medial or lateral collateral ligament injuries [1]. Reconstruction of bicruciate multiligament knee injuries with repair or reconstruction of associated collateral ligament injuries improves clinical outcomes [5]. Arthroscopic-assisted reconstruction of the cruciate ligaments and repair or reconstruction of the collateral ligament and other injured structures resulted in 45% of patients having good subjective results and functional stability and 45% having satisfactory subjective and functional stability within 2 to 3 weeks after surgery [6]. For chronic combined knee instabilities, MCL reconstruction can be safely performed using hamstring tendon autografts, with favorable clinical outcomes and satisfactory stability at a minimum 2-year follow-up [12]. Clinical outcomes using IKDC evaluation indicate no major difference exists between isolated MCL injury and combined MCL-ACL injury treated with a double-bundle allograft technique [26].

Acute simultaneous reconstruction of ACL injury and grade III MCL injury resulted in excellent functional outcomes, with return to the same level of sports in the majority of patients at short-term follow-up [43]. A systematic approach to chronic posterolateral instability combining bony axial correction, collateral and central ligament reconstruction can result in significant amelioration of function and positive outcomes for activities of daily living and low-level athletic activities [8]. Functional outcomes for combined anterior or posterior cruciate ligament and posterolateral corner injuries were satisfactory but less good than those reported after surgical reconstruction of isolated cruciate ligament tears [13]. There is a paucity of literature focused on the management of combined ACL and posterolateral corner injuries [14]. Extra-articular anterolateral procedures have undergone a renaissance in combination with ACL reconstruction in selected cases, but there is a clear need for more high-level clinical evidence to support their routine use [44]. Patients with concomitant MCL injuries, particularly those managed operatively at the time of ACL reconstruction, are at increased risk of requiring revision ACL reconstruction compared with those with isolated ACL injuries [57]. Failure of meniscal repair is seen more commonly in medial-sided repairs and with failure of ACL reconstruction [11]. A treatment protocol exists to help determine the surgical management of grade 3 medial knee injuries combined with cruciate ligament injuries [25].

Anatomy & Pathophysiology

Bony Anatomy and Landmarks

The femoral insertion site of the superficial MCL is located a mean 1.6 mm posterior and 4.9 mm proximal to the intersection between a line paralleling the posterior femoral cortex and a line drawn perpendicular to the posterior femoral cortex where it intersects the Blumensaat line [98]. Chronic MCL injuries may present with calcification at the insertion of the MCL on the medial femoral condyle [30]. A Pellegrini-Stieda lesion is defined as a calcification at the medial femoral insertion site resulting from chronic MCL deficiency [46].

Ligamentous Anatomy and Layers

The medial side of the knee is described in three layers: layer 1 is the deep fascia, layer 2 is the superficial MCL, and layer 3 is the joint capsule and deep MCL [46]. The medial capsuloligamentous complex comprises a three-layered sleeve of static and dynamic stabilizers extending from the midline anteriorly to the midline posteriorly [47]. The static stabilizers of the medial knee include the superficial MCL, the posterior oblique ligament, and the deep MCL [47]. The deep MCL is also referred to as the deep medial ligament or middle capsular ligament [47]. The dynamic stabilizers of the medial knee include the semimembranosus complex, the pes anserinus muscle group, the vastus medialis, and the medial retinaculum [47]. The semimembranosus complex is composed of five insertional attachments [47]. The pes anserinus muscle group consists of the sartorius, gracilis, and semitendinosus muscles [47].

The MCL is a long, narrow structure lying superficial to the medial capsule and capsular ligaments [90]. It originates on the medial epicondyle and inserts 7 to 10 cm below the joint line on the posterior half of the medial surface of the tibial metaphysis deep to the pes anserinus tendons [90]. The MCL glides forward over the side of the femoral condyle in extension and posteriorly in flexion [90]. The posterior oblique ligament is the predominant ligamentous structure on the posterior medial corner of the knee joint [133].

Vascular & Neural Anatomy

The MCL receives its blood supply from the superior medial and inferior medial geniculate arteries [46]. The perpendicular mean distance from the saphenous nerve to the adductor tubercle is 5 cm [98]. The perpendicular mean distance from the saphenous nerve to the medial epicondyle is 6.1 cm [98]. The perpendicular mean distance of the sartorial branch of the saphenous nerve to the anterior aspect of the superficial MCL is 4.8 cm at a point 2 cm distal to the joint line, 4.1 cm at a point 4 cm distal to the joint line, and 3.8 cm at a point 6 cm distal to the joint line [98].

Biomechanics and Restraints

The main function of the medial capsuloligamentous complex is to resist valgus and external rotation loads [47]. The superficial MCL is the primary restraint to valgus stress [46] and specifically to valgus loads at 30° of flexion [47]. The long fibers of the MCL are the primary stabilizers of the medial side of the knee against valgus and external rotary stress [90]. The deep MCL and posterior oblique ligaments form the secondary restraints to valgus stress [46], alongside the cruciate ligaments [47]. The semimembranosus, vastus medialis, medial retinaculum, sartorius, semimembranosus, and gracilis act as dynamic stabilizers of the medial knee [46].

In a healthy knee, the anterior bundles of both the superficial and deep MCL elongate during knee flexion [98]. Conversely, the posterior bundles of the superficial and deep MCL distend with knee flexion [98]. The elongation of the posterior bundles of the MCL peaked at midstance and the terminal extension–preswing stance phase [98]. The anterior fibers of the MCL tighten as the knee flexes, while fibers more posteriorly become slack [90]. The superficial MCL with intact femoral and distal tibial attachments has the highest load to failure and stiffness among medial knee ligaments, followed by the POL and the deep MCL [98]. The MCL and LCL showed no significant difference in stiffness, but the ultimate tensile strength of the MCL was twice that of the LCL [98].

A significant increase in displacement is observed after all medial knee structures are sectioned for valgus angulation, external rotation, internal rotation (from 0° to 60° only), anterior tibial translation (from 20° to 90° only), and posterior tibial translation (from 0° to 30° only) [98]. Under normal knee joint motion with 5 degrees of freedom, the functional deficit of the MCL in valgus rotation is compensated for by remaining structures, especially the ACL [108]. The calculated tensioning effect of the semimembranosus corner was small in all flexion angles for all simulated laxity tests [99]. One study defines the length-change patterns of the superficial MCL, deep MCL, and POL across knee flexion and under various loads [75].

Reconstruction Kinematics

The optimal position for MCL reconstruction to reproduce native knee kinematics is at the center of the femoral attachment and the center of the superficial MCL attachment, which is the most isometric point [98]. Minor variations of the insertion sites for MCL reconstruction significantly modify graft excursion [98]. An anatomic MCL reconstruction (superficial MCL and POL) completely restored stability for valgus angulation as well as external and internal rotation but did not restore anterior and posterior tibial translation [98]. Nonanatomic MCL reconstruction using a shorter graft technique produced greater tibial external rotation during active knee extension and passive stability testing conditions compared with anatomic superficial MCL reconstruction [98]. Anatomic superficial MCL reconstruction restored normal knee kinematics and stability [98].

Injury Patterns and Pathophysiology

The MCL is the most commonly injured ligament in the knee [46]. The mechanism of MCL injury is a valgus and external rotation force to the lateral knee [46]. Lesser degrees of MCL sprains result from a noncontact valgus, external rotation force [47], while complete MCL disruption usually results from a direct blow to the lateral aspect of the knee [47]. The most common injury location for the MCL is the femoral insertion, which has great healing potential [46]. The MCL was most commonly torn at the femoral insertion site [98]. Distal MCL ruptures are less common and more often lead to residual valgus laxity [46].

Concomitant ligamentous injuries occur in 20% of grade I, 52% of grade II, and 78% of grade III MCL injuries [47]. Concomitant ligamentous injuries in MCL trauma occur in the ACL in 95% of cases [47]. Concurrent meniscal injuries have been noted in up to 5% of isolated MCL injuries [47]. This study found alterations in the native load-sharing relationships of the medial knee structures after injury [86]. The study suggests progressive damage to translational and rotational knee soft-tissue restraints with increasing knee hyperextension [91].

Isolated grade III superficial MCL injury in a cadaver model resulted in a mean increase of 3.2 mm in medial joint line opening [98]. A cutoff distance of 3.2 mm of medial joint line opening was established as the basis for suspecting an isolated grade III superficial MCL injury [98]. In the intact state, medial joint line opening increased to 8.8 mm when the deep MCL and posterior oblique ligament were injured [98]. In the intact state, medial joint line opening increased to 13.8 mm when ACL injury was added to deep MCL and POL injury [98].

Three different POL injury patterns have been reported: those associated with injury to the capsular arm of the semimembranosus, those involving a complete peripheral meniscal detachment, and those involving disruption of the semimembranosus and peripheral meniscal detachment [133]. The hallmark of an injury related to POL lesions is the presence of anteromedial rotatory instability (AMRI), defined as external rotation with anterior subluxation of the medial tibial plateau relative to the distal femur [133]. An MRI-based retrospective study found that 81% of patients with a confirmed knee dislocation or a knee dislocatable under anesthesia had an injury to the posteromedial corner [114]. An MRI-based retrospective study found that 63% of patients with a confirmed knee dislocation or a knee dislocatable under anesthesia had a superficial MCL tear alone [114]. All patients with injury to the posterior horn of the medial meniscus had concomitant meniscotibial ligament injury [114]. 67% of patients with injury to the posterior horn of the medial meniscus had a tear of the POL [114]. All patients with grade III laxity of the MCL had a complete tear of the POL and meniscotibial ligament [114].

Classification

MCL Grading Systems

The American Medical Association Standard Nomenclature of Athletic Injuries classifies superficial MCL injuries into grades I–III [37]. Grade I is defined by the absence of valgus gapping [37]. Grade II presents with clearly increased medial joint gapping but retains a clear endpoint [37]. Grade III is characterized by clear laxity without any endpoint to an applied valgus stress [37]. Isolated medial knee injuries are classified by the amount of laxity observed at 30° of knee flexion with a valgus applied moment [37]. Grades 1+, 2+, and 3+ correspond to 3–5 mm, 6–10 mm, and >10 mm of subjective medial joint line gapping laxity compared to the non-injured contralateral side, respectively [37]. A finding of valgus laxity at 0° indicates a concomitant cruciate ligament injury [37]. Alternatively, valgus laxity at 0° can represent an injury and laxity of the posteromedial structures, including the posterior oblique ligament [37].

Multiligament Knee Injury (MLKI) and Knee Dislocation (KD) Classifications

Schenck: The Schenck classification is the most commonly used anatomically based classification system for multiligament knee injuries, initially described in 1994 [22]. Wascher and colleagues modified the system in 1997 to include vascular injuries and specify medial versus lateral injuries [22]. Robert Schenck detailed the classification in a 2003 article, concluding that classifying knee dislocation is best performed based on what structures are torn [22]. This system allows for communication and surgical planning [22]. It serves as a useful communication, planning, and prognostic tool for evaluating potential associated neurovascular injuries in knee dislocations [107]. However, the Schenck classification does not directly address the energy of injury, though Schenck recommended surgeons take this into account [22]. It lacks the necessary specificity to facilitate accurate and consistent reporting and does not consistently guide clinical decision making [22]. Additionally, the Schenck classification neglects to include the posteromedial corner [53].

Poploski et al.: The Poploski et al. classification is a modification of the Schenck classification designed to encompass MLKIs separately from KDs [113]. It expanded MLKI to include collateral ligamentous injuries occurring alongside isolated cruciate ligamentous injuries [113]. This system designates clinically incompetent ligaments as third-degree injuries for MLKI classification purposes [113]. It relies on the involvement of ligamentous structures to define injury patterns rather than a knee dislocation [113]. The Poploski et al. classification does not include a class 5 or KDV-equivalent category [113].

Classification Utility and Limitations

Separation of injury patterns into distinct classifications for knee dislocations and multiple ligament knee injuries allows researchers to stratify by newer modifications [52]. These distinct classifications show potential for assisting in patient prognosis [52]. The KD classification alone was not predictive of surgery timing, staging, or any type of intervention for any injured ligament [41]. An association between Schenck KD grade and neurovascular lesions has yet to be established [36]. The Schenck classification was used to group patient data in a meta-analysis of primary ligament sutures for knee dislocations [119]. A classification system developed for PCL reconstruction documents the degree of laxity at the time of surgical treatment rather than at the time of injury [116]. This PCL classification system was not useful to predict prognosis after treatment [116].

Clinical Presentation

History and Mechanism

MCL injuries result from valgus stress to the knee or noncontact rotational injury [30]. Lower-grade injuries typically follow a noncontact external rotational mechanism, whereas higher-grade injuries generally involve lateral contact to the thigh or upper leg [30]. Immediate swelling following injury raises suspicion for associated cruciate ligament injury, fracture, and/or patellar dislocation [30]. In patients with ankle fractures, female sex and pronation injury of the ankle are significantly associated with medial collateral ligament injury of the knee [21].

Physical Examination

Medial knee pain and instability at 30 degrees of flexion is diagnostic for MCL injury [30]. Valgus stress testing should be performed at 30 degrees of flexion because the posterior capsule and PCL stabilize the knee to valgus stress in full extension [30]. A finding of valgus laxity at 0 degrees indicates a concomitant cruciate ligament injury or injury and laxity of the posteromedial structures including the posterior oblique ligament [37]. Medial joint line tenderness along the course of the MCL is typical at the location of the tear [30]. Palpation of the patella and medial parapatellar stabilizing ligaments, along with patellar apprehension testing, should be performed due to the frequency of coexisting patellar dislocations in MCL injuries [30].

Grading and Stability

Zero medial joint space opening to valgus stress is considered normal [30]. Injury grading is determined by the degree of medial joint space opening at 30 degrees of flexion and the presence of an endpoint: * Grade I: 1–4 mm of medial joint space opening [30]; characterized by no valgus gapping [37] and a firm end point to valgus stress [30]. * Grade II: 5–9 mm of medial joint space opening [30]; characterized by clearly increased medial joint gapping with a clear endpoint [37] and a firm end point to valgus stress [30]. * Grade III: 10–15 mm of medial joint space opening [30]; characterized by clear laxity without any endpoint to an applied valgus stress [37] and a soft end point to valgus stress [30].

Grades 1+, 2+, and 3+ of isolated medial knee injuries correspond to 3–5 mm, 6–10 mm, and >10 mm of subjective medial joint line gapping laxity compared to the non-injured contralateral side [37].

Imaging

MRI is useful for confirming MCL injury and identifying the site of injury [30]. It is also useful to detect the presence of meniscal and other injuries to the knee [30]. Relative indications for MRI include uncertain ACL status despite multiple examinations, evaluation of a suspected meniscal tear, or preoperative evaluation for a planned MCL reconstruction or repair [30]. In acute knee dislocation, MRI is a sensitive measure of cruciate and collateral ligament injury [31], but it does not reliably diagnose injury to the posterolateral corner or meniscus [31].

Radiographs should be inspected for acute fracture, lateral capsular avulsion (Segond fracture), loose bodies, Pellegrini-Stieda lesion (MCL calcification), and evidence of patellar dislocation [30]. Stress radiographs should be obtained in patients prior to skeletal maturity to rule out an epiphyseal fracture [30]. Additionally, stress radiographs support accurate diagnosis of complex knee injuries and provide an objective measure of knee stability following ligament reconstruction [33].

Investigations

Clinical Examination

Medial knee pain and instability at 30 degrees of flexion is diagnostic for medial collateral ligament injury [30]. Valgus stress testing at 30 degrees of flexion isolates the superficial medial collateral ligament, as the posterior capsule and posterior cruciate ligament stabilize the knee to valgus stress in full extension [30]. Laxity is assessed by the amount of medial joint space opening at 30 degrees of flexion [30]. Zero opening is considered normal, with 1–4 mm indicating a grade I injury, 5–9 mm indicating a grade II injury, and 10–15 mm indicating a complete or grade III injury [30]. Grade I and II injuries typically have a firm end point to valgus stress, whereas a grade III injury tends to have a soft end point [30]. Valgus stress should be applied at both 0° and 30° of flexion, with opening at 0° indicating a posteromedial capsular or associated cruciate ligament injury [46]. Opening at full extension with a valgus stress suggests concomitant anterior cruciate ligament or posterior cruciate ligament injuries [30]. The pivot shift test often has false-negative results in the presence of a grade III medial collateral ligament sprain [47]. An examination under anesthesia can be valuable when physical examination is unreliable because of patient guarding [30].

Imaging

Plain radiography: Plain radiographs should be inspected for acute fracture, lateral capsular avulsion (Segond fracture), loose bodies, Pellegrini-Stieda lesion (medial collateral ligament calcification), and evidence of patellar dislocation [30]. Intra-articular fractures of the distal femoral epiphysis can mimic ligamentous injuries, particularly posterior cruciate ligament insufficiency, and require stress radiographs for diagnosis [139].

MRI: MRI is useful for confirming medial collateral ligament injury and identifying the site of injury [30]. Relative indications for MRI include uncertain anterior cruciate ligament status despite multiple examinations, evaluation of a suspected meniscal tear, or preoperative evaluation for a planned medial collateral ligament reconstruction or repair [30]. MRI findings, including direct signs like fiber discontinuity and indirect signs like bone contusions, correlate well with arthroscopic findings for anterior cruciate ligament, posterior cruciate ligament, and posterolateral corner injuries [138]. However, MRI does not reliably diagnose injury to the posterolateral corner or meniscus in acute knee dislocation, requiring a higher index of suspicion during arthroscopy [31]. Measurement using an open magnetic resonance imaging successfully quantified the remaining rotatory instability in anterior cruciate ligament–reconstructed knees [132].

Ultrasonography: Dynamic ultrasonographic assessment can accurately quantify the severity of medial knee ligament injury based on medial compartment gapping [135].

Arthroscopy

Diagnostic arthroscopy can be used to evaluate for coexisting pathology, though it has largely been replaced by MRI for this purpose [30]. During arthroscopy, the "floating meniscus" sign is observed as nonphysiological positioning of the medial meniscus with abnormal opening of the medial compartment when meniscotibial coronary ligaments from the deep medial collateral ligament are disrupted [48]. This sign is believed to indicate medial meniscus avulsion from the tibial plateau [48].

Treatment

Non-Operative

Conservative treatment is the recommended initial management for acute medial collateral ligament (MCL) ruptures, even when an anterior cruciate ligament (ACL) injury is present [4]. Nonoperative management of MCL tears performed in conjunction with autogenous bone-patellar tendon-bone intraarticular ACL reconstruction provides excellent stability and good to excellent functional outcomes [50]. Clinical outcomes for MCL injuries treated nonoperatively alongside ACL reconstruction are similar to those of isolated ACL reconstruction without an MCL injury at 2-year follow-up [32]. For isolated MCL injuries, nonoperative treatment using a hinged knee brace is highly successful in alleviating symptoms [71]. Clinical work demonstrates the advantage of nonoperative bracing for associated MCL injuries in patients undergoing ACL reconstruction [71]. The location of injury in the superficial layer may help predict the outcome of nonoperative treatment for acute grade III MCL lesions combined with ACL injury [3]. However, the current literature on non-operative treatment of isolated MCL injuries is scarce and ranges from low to moderate quality of evidence [125].

Operative

Indications: A one-stage protocol with early surgery rather than delayed reconstruction produces better clinical outcomes for multiligament injured knees, regardless of whether the medial or lateral collateral ligament is injured [1]. Early operative treatment of the multiligament-injured knee yields improved functional and clinical outcomes compared with nonoperative management or delayed surgery [126]. Acute operative treatment is considered for intraarticular ligamentous entrapment, avulsion injuries, ruptures in combination with tibial plateau fractures, anteromedial rotatory instability, or valgus instability in an underlying valgus knee alignment [85]. There is a trend towards early surgical reconstruction (within 3 weeks of injury) performed in a single-stage to allow for earlier postoperative rehabilitation for multiligamentous knee injuries [104]. Conversely, surgical treatment of the MCL injury was associated with worse two-year patient-reported knee function compared to non-surgical treatment in a study of 19,457 patients [40].

Surgical Approach / Technique: A mini-invasive medial ligament plasty to repair the MCL restored medial stability and knee function to normal or nearly normal in all 36 patients with combined chronic ACL and Grade II or III medial instability [24]. In a 3-arm randomized controlled trial, MCL repair, isolated suture-tape bracing, and no repair for grade III MCL tears during ACL reconstruction resulted in similar outcomes for combined ACL-MCL injuries [62]. Clinical outcomes using IKDC evaluation indicate no major difference exists between isolated MCL injury and combined MCL-ACL injury treated with a triangular vector double-bundle allograft technique [26]. Anatomical sMCL and POL reconstruction may produce slightly better biomechanical stability than triangular reconstruction, but triangular reconstruction restores near-normal knee joint function and is less invasive and more practical [34]. A novel technique for combined MCL and posterior oblique ligament reconstruction is easily reproducible and restores medial stability immediately after surgery [55]. Early evidence suggests that with improved suture material and implants, ligament suture repair can provide equally successful outcomes as ligament reconstruction in the multiligament injured knee [123].

Other Considerations: The surgical management of multi-ligament knee injuries confers a significant increased risk of 30-day post-operative minor or severe adverse events over arthroscopic ACL reconstruction [42]. Modern multiligament knee injury surgical reconstruction techniques can achieve excellent knee function and patient satisfaction with low complication rates [104]. In a series of 36 patients undergoing multiligament repair or reconstruction, early physical therapy initiated on postoperative day 1 was compared to late rehabilitation in a pilot randomized clinical trial [95]. For KDIIIM multiligamentous knee injuries treated with PCL inlay and MCL reconstruction, patients are kept nonweightbearing for 6 weeks, protected in a brace locked in extension for 2 weeks, and allowed ROM from full extension to 70° of flexion from weeks 2 through 6 [110]. A systematic approach to chronic posterolateral instability combining bony axial correction, collateral and central ligament reconstruction can result in significant amelioration of function and positive outcomes for activities of daily living and low-level athletic activities [8]. An anatomic PLC reconstruction, concomitant to other surgical procedures, is a valid technique in multiligamentous knee injury involving the PLC, improving subjective outcomes and objective stability in patients with chronic PLC knee injury [9]. The repaired lateral side and untreated posterior cruciate ligament heal with continuity, allowing patients to return to high levels of activity in cases of knee dislocation with lateral side injury [20].

Complications

Surgical Complications

Adverse Events: Surgical management of multi-ligament knee injuries confers a significant increased risk of 30-day post-operative minor or severe adverse events compared to arthroscopic ACL reconstruction [42].

Nerve Palsy: In the setting of posterolateral corner surgery, variability in complex anatomy and soft-tissue trauma predisposes patients to peroneal nerve injury [10]. There is a significant risk of peroneal nerve injury associated with lateral-sided knee dislocation injuries [39].

Wound Complications and Infection: Surgical management of posterolateral corner injuries carries risks of wound complications and infection [10].

Stiffness / Arthrofibrosis: Surgical management of posterolateral corner injuries carries a risk of arthrofibrosis [10].

Other Considerations: Cartilage injuries were common in patients with chronically treated knee dislocations [39]. MRI does not reliably diagnose injury to the posterolateral corner or meniscus in acute knee dislocation, requiring a higher index of suspicion during arthroscopy to prevent misdiagnosis that could affect long-term clinical outcome [31].

Graft and Ligament Failure

Instability: MCL deficiency increases the risk of ACL graft failure following combined ACL and MCL injury [129]. Anteromedial rotatory instability may persist following combined ACL and MCL injury if there is inadequate healing of both the superficial and deep MCL [129].

Graft Failure: Meniscal repair failure is seen more commonly in medial-sided repairs and with failure of ACL reconstruction [11]. As the time from initial double-bundle ACL reconstruction to revision surgery increases, the pattern of injury more closely resembles that of the native ACL [67].

Functional and Quality of Life Outcomes

Quality of Life: Patients with a previous history of knee ligament surgery had a significantly worse quality of life relative to those with no history of knee ligament surgery [58].

Functional Outcomes: Functional outcomes for combined cruciate and posterolateral corner injuries were satisfactory but less good than those reported after surgical reconstruction of isolated cruciate ligament tears [13].

Recovery

Light activity (weeks): In a described method of arthroscopic-assisted reconstruction of cruciate ligaments and repair or reconstruction of collateral ligaments, 45% of patients achieved good subjective results and functional stability within 2 to 3 weeks after surgery [6].

Other Considerations: Surgical management of medial collateral ligament injuries is associated with a worse two-year patient-reported knee function compared to non-surgical treatment [40]. Early observations suggest that anatomic medial knee reconstruction techniques improve overall patient function and restore valgus instability [45]. Anatomic posterolateral corner reconstruction, concomitant to other surgical procedures, improves subjective outcomes and objective stability in patients with chronic posterolateral corner knee injury [9]. Medial collateral ligament reconstruction for chronic combined knee instabilities using hamstring tendon autografts can be safely performed, with favorable clinical outcomes and satisfactory stability at a minimum 2-year follow-up [12]. Acute combined repair and reconstruction with LARS ligaments is a valid alternative for treating knee dislocations, with findings based on a mean follow-up of 54 months [64].

Key Evidence

  • [L4] A one-stage protocol with early surgery rather than delayed reconstruction produced better clinical outcomes whatever the injured collateral ligament, medial or lateral. [1] (10.1007/s00167-016-4067-4)
  • [L5] Most isolated medial collateral ligament injuries are treated nonsurgically, while concomitant damage to the anterior or posterior cruciate ligaments is a common indication for surgical management of high-grade injuries. [2] (10.5435/00124635-200903000-00004)
  • [L3] Location of injury in the superficial layer may be useful in predicting the outcome of nonoperative treatment for acute grade III medial collateral ligament lesions combined with anterior cruciate ligament injury. [3] (10.1177/03635465030310021801)
  • [L2] The authors recommend that conservative treatment should be used in the initial treatment of acute ruptures of the medial collateral ligament even in the presence of anterior cruciate ligament injury. [4] (10.1016/0020-1383(89)90167-8)
  • [L3] Reconstruction of bicruciate MLKIs with repair or reconstruction of associated collateral ligament injuries improves clinical outcomes. [5] (10.1177/23259671251319532)
  • [L4] By use of the described method of arthroscopic-assisted reconstruction of the cruciate ligaments and repair or reconstruction of the collateral ligament and other injured structures, 45% of the patients had good subjective results and functional stability and 45% had satisfactory subjective and functional stability within 2 to 3 weeks after surgery. [6] (10.1016/j.arthro.2007.08.007)
  • [L4] A systematic approach to chronic posterolateral instability of the knee combining bony axial correction, collateral and central ligament reconstruction can result in significant amelioration of function and positive outcomes for ADL and low level athletic activities. [8] (10.1016/j.arthro.2013.07.136)
  • [L4] The presented anatomic PLC reconstruction, concomitant to other surgical procedures and ligament reconstructions, is a valid technique in a multiligamentous knee injury involving the PLC, improving subjective outcomes and objective stability in patients with a chronic PLC knee injury, similar to historical controls. [9] (10.1016/j.arthro.2019.01.016)
  • [L5] [10] (10.5435/jaaos-d-23-00278)
  • [L4] Failure is seen more commonly in medial sided repairs and with failure of ACL reconstruction. [11] (10.1007/s00167-020-06189-w)
  • [L4] Medial collateral ligament reconstruction for chronic combined knee instabilities can be safely performed using hamstring tendon autografts, and the clinical outcome with a minimum 2-year follow-up was favorable with satisfactory stability. [12] (10.1177/0363546513485716)
  • [L3] Functional outcomes were satisfactory but less good than those reported after surgical reconstruction of isolated cruciate ligament tears. [13] (10.1016/j.otsr.2014.09.010)
  • [L4] There is a paucity of literature focused on the management of combined ACL and PLC injuries. [14] (10.1177/0363546513507555)
  • [L4] The repaired lateral side and untreated posterior cruciate ligament heal with continuity, allowing patients to return to high levels of activity. [20] (10.1177/0363546507299444)
  • [L3] Female sex and pronation injury were significantly associated with medial collateral ligament (MCL) injury of the knee in patients with ankle fractures. [21] (10.1007/s00402-018-2907-z)
  • [Paper] [22] (10.1016/j.csm.2018.11.006)
  • [L4] [24] (10.1007/s11999-011-2018-4)
  • [L4] This treatment protocol can help determine the surgical management of grade 3 medial knee injuries combined with cruciate ligament injuries. [25] (10.1007/s00167-011-1541-x)
  • [L4] The clinical outcomes using IKDC evaluation indicate that no major difference exists in isolated MCL injury and combined MCL-ACL injury treated with this new technique. [26] (10.1016/j.arthro.2012.03.024)
  • [L2] MRI is a sensitive measure of cruciate and collateral ligament injury in acute knee dislocation; however, it does not reliably diagnose injury to the posterolateral corner or meniscus, and therefore, a higher index of suspicion is required during arthroscopy to prevent misdiagnosis which could affect long-term clinical outcome. [31] (10.1007/s00167-015-3857-4)
  • [L3] Nonoperative treatment for MCL injuries combined ACL reconstruction is an effective treatment and provides similar clinical outcomes to those of isolated ACL reconstruction without an MCL injury. [32] (10.1016/j.jisako.2025.100515)
  • [L5] Stress radiographs support accurate diagnosis of complex knee injuries and provide an objective measure of knee stability following ligament reconstruction. [33] (10.1016/j.arthro.2020.11.001)
  • [L5] Anatomical sMCL and POL reconstruction may produce slightly better biomechanical stability than the triangular reconstruction, but the triangular reconstruction may restore a near-normal knee joint and is both less invasive and more practical. [34] (10.1186/s12891-018-2039-1)
  • [L3] [36] (10.1177/23259671241312697)
  • [L5] [37] (10.1007/s00167-015-3675-8)
  • [L3] Cartilage injuries were common in chronically treated patients, and there was a significant risk of peroneal nerve injury with lateral-sided injuries. [39] (10.1177/2325967117706521)
  • [L3] However, surgical treatment of the MCL injury was associated with a worse two-year patient-reported knee function. [40] (10.1007/s00167-018-5237-3)
  • [L3] The KD classification alone was not predictive of surgery timing, staging, or any type of intervention for any injured ligament. [41] (10.1055/s-0039-1695739)
  • [L4] The surgical management of multi-ligament knee injuries confers significant increased risk of 30-day post-operative minor or severe adverse events over arthroscopic ACL reconstruction. [42] (10.1007/s00167-020-06252-6)
  • [L4] This procedure resulted in excellent functional outcomes, with return to the same level of sports in the majority of patients at short-term follow-up. [43] (10.1177/2325967117s00031)
  • [Paper] Extra-articular anterolateral procedures have undergone a renaissance in combination with anterior cruciate ligament reconstruction in selected cases, but there is a clear need for more high-level clinical evidence to support their routine use. [44] (10.1016/j.csm.2017.07.008)
  • [L4] Early observations suggest this anatomic reconstruction technique improves overall patient function and restores valgus instability. [45] (10.1007/s11999-011-2061-1)
  • [L1] [48] (10.1016/j.arthro.2018.10.114)
  • [L4] Nonoperative management of MCL tears in conjunction with autogenous bone-patellar tendon-bone intraarticular ACL reconstruction of combined ACL-MCL injuries can give excellent stability and good to excellent functional outcome. [50] (10.1177/036354659202000308)
  • [L5] Separation of injury patterns into distinct classifications for knee dislocations and multiple ligament knee injuries allows researchers to stratify by newer modifications and shows potential for assisting in patient prognosis. [52] (10.1016/j.arthro.2025.05.011)
  • [L4] [53] (10.1007/s00167-009-1011-x)
  • [L4] This technique is easily reproducible and useful and restores the medial stability immediately after surgery. [55] (10.1007/s00167-015-3721-6)
  • [L3] Patients with concomitant MCL injuries, particularly those managed operatively, at the time of ACLR are at increased risk of requiring revision ACLR compared with those with isolated ACL injuries. [57] (10.1016/j.arthro.2024.06.016)
  • [L4] Patients with a previous history of knee ligament surgery had a significantly worse quality of life relative to those with no history of knee ligament surgery. [58] (10.1177/2325967115s00073)
  • [L1] [62] (10.1016/j.arthro.2024.09.023)
  • [L4] Our findings suggest that with a mean follow-up of 54 months, acute combined repair and reconstruction with LARS ligaments is a valid alternative for treating knee dislocations. [64] (10.1007/s00264-010-1154-x)
  • [L4] As the length of time from the initial DB-ACL reconstruction to revision surgery increased, the pattern of injury more closely resembled that of the native ACL. [67] (10.1007/s00167-010-1297-8)
  • [L5] The study defines the length-change patterns of the superficial MCL, deep MCL, and POL across knee flexion and under various loads, providing biomechanical data to inform surgical repair or reconstruction strategies. [75] (10.1007/s00167-020-06050-0)
  • [L5] [85] (10.1007/s00167-014-3326-5)
  • [L5] This study found alterations in the native load-sharing relationships of the medial knee structures after injury. [86] (10.1177/0363546509335191)
  • [L5] The study suggests progressive damage to translational and rotational knee soft-tissue restraints with increasing knee hyperextension. [91] (10.1177/0363546507308189)
  • [L2] [95] (10.1097/corr.0000000000001729)
  • [L5] The calculated tensioning effect was small in all flexion angles for all simulated laxity tests. [99] (10.1177/0363546519829384)
  • [L4] [104] (10.1002/ksa.12332)
  • [Paper] Despite limitations in validation, the Schenck classification serves as a useful communication, planning, and prognostic tool for evaluating potential associated neurovascular injuries in knee dislocations. [107] (10.1097/corr.0000000000001186)
  • [L5] Under normal knee joint motion with 5 degrees of freedom, the functional deficit of the MCL in valgus rotation is compensated for by remaining structures, especially the ACL. [108] (10.1177/036354658701500103)
  • [L4] [110] (10.1007/s11999-014-3557-2)
  • [L4] [113] (10.1177/23259671251320981)
  • [L4] [116] (10.1177/0363546503261511)
  • [L1] [119] (10.1007/s00167-012-2154-8)
  • [L5] Early evidence suggests improved clinical outcomes with ligament reconstruction, but with improved suture material and implants, ligament suture repair can provide equally successful outcomes. [123] (10.1016/j.csm.2018.11.008)
  • [L4] The current literature on non-operative treatment of isolated MCL injuries is scarce and ranges from low to moderate quality of evidence. [125] (10.1016/j.jisako.2025.100835)
  • [L2] Our review suggests that early operative treatment of the multiligament-injured knee yields improved functional and clinical outcomes compared with nonoperative management or delayed surgery. [126] (10.1016/j.arthro.2009.01.008)
  • [L5] Following combined ACL and MCL injury, anteromedial rotatory instability may persist if there is inadequate healing of both the superficial and deep MCL, and MCL deficiency increases the risk of ACL graft failure. [129] (10.1007/s00167-020-06084-4)
  • [L4] Measurement using an open magnetic resonance imaging successfully quantified the remaining rotatory instability in anterior cruciate ligament–reconstructed knees. [132] (10.1177/0363546508330134)
  • [L5] [133] (10.1302/2058-5241.6.200127)
  • [L5] Dynamic ultrasonographic assessment can accurately quantify the severity of medial knee ligament injury based on medial compartment gapping. [135] (10.1016/j.asmr.2022.07.003)
  • [L4] MRI findings, including direct signs like fiber discontinuity and indirect signs like bone contusions, correlate well with arthroscopic findings for ACL, PCL, and posterolateral corner injuries, aiding in the diagnosis and surgical planning of knee pathologies. [138] (10.1016/j.csm.2013.03.004)
  • [Case_report] Intra-articular fractures of the distal femoral epiphysis can mimic ligamentous injuries, particularly posterior cruciate ligament insufficiency, and require stress radiographs for diagnosis. [139] (10.2106/00004623-198870030-00024)

See Also

References

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c. For the avoidance of doubt, the Licensor may also offer the Licensed Material under separate terms or conditions or stop distributing the Licensed Material at any time; however, doing so will not terminate this Public License.

d. Sections 1, 5, 6, 7, and 8 survive termination of this Public License.

Section 7 -- Other Terms and Conditions.

a. The Licensor shall not be bound by any additional or different terms or conditions communicated by You unless expressly agreed.

b. Any arrangements, understandings, or agreements regarding the Licensed Material not stated herein are separate from and independent of the terms and conditions of this Public License.

Section 8 -- Interpretation.

a. For the avoidance of doubt, this Public License does not, and shall not be interpreted to, reduce, limit, restrict, or impose conditions on any use of the Licensed Material that could lawfully be made without permission under this Public License.

b. To the extent possible, if any provision of this Public License is deemed unenforceable, it shall be automatically reformed to the minimum extent necessary to make it enforceable. If the provision cannot be reformed, it shall be severed from this Public License without affecting the enforceability of the remaining terms and conditions.

c. No term or condition of this Public License will be waived and no failure to comply consented to unless expressly agreed to by the Licensor.

d. Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.

Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” The text of the Creative Commons public licenses is dedicated to the public domain under the CC0 Public Domain Dedication. Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark "Creative Commons" or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.

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