The posteromedial corner of the knee encompasses five medial structures posterior to the medial collateral ligament. With modern MRI systems, these structures are readily identified and can be ...appreciated in the context of multiligamentous knee injuries. It is recognized that anteromedial rotatory instability results from an injury that involves both the medial collateral ligament and the posterior oblique ligament. Like posterolateral corner injuries, untreated or concurrent posteromedial corner injuries resulting in rotatory instability place additional strain on anterior and posterior cruciate ligament reconstructions, which can ultimately contribute to graft failure and poor clinical outcomes. Various options exist for posteromedial corner reconstruction, with early results indicating that anatomic reconstruction can restore valgus stability and improve patient function. A thorough understanding of the anatomy, physical examination findings, and imaging characteristics will aid the physician in the management of these injuries.
Purpose
To define the length-change patterns of the superficial medial collateral ligament (sMCL), deep MCL (dMCL), and posterior oblique ligament (POL) across knee flexion and with applied anterior ...and rotational loads, and to relate these findings to their functions in knee stability and to surgical repair or reconstruction.
Methods
Ten cadaveric knees were mounted in a kinematics rig with loaded quadriceps, ITB, and hamstrings. Length changes of the anterior and posterior fibres of the sMCL, dMCL, and POL were recorded from 0° to 100° flexion by use of a linear displacement transducer and normalised to lengths at 0° flexion. Measurements were repeated with no external load, 90 N anterior draw force, and 5 Nm internal and 5 Nm external rotation torque applied.
Results
The anterior sMCL lengthened with flexion (
p
< 0.01) and further lengthened by external rotation (
p
< 0.001). The posterior sMCL slackened with flexion (
p
< 0.001), but was lengthened by internal rotation (
p
< 0.05). External rotation lengthened the anterior dMCL fibres by 10% throughout flexion (
p
< 0.001). sMCL release allowed the dMCL to become taut with valgus rotation (
p
< 0.001). The anterior and posterior POL fibres slackened with flexion (
p
< 0.001), but were elongated by internal rotation (
p
< 0.001).
Conclusion
The structures of the medial ligament complex react differently to knee flexion and applied loads. Structures attaching posterior to the medial epicondyle are taut in extension, whereas the anterior sMCL, attaching anterior to the epicondyle, is tensioned during flexion. The anterior dMCL is elongated by external rotation. These data offer the basis for MCL repair and reconstruction techniques regarding graft positioning and tensioning.
*The superficial medial collateral ligament and other medial knee stabilizers-i.e., the deep medial collateral ligament and the posterior oblique ligament-are the most commonly injured ligamentous ...structures of the knee. *The main structures of the medial aspect of the knee are the proximal and distal divisions of the superficial medial collateral ligament, the meniscofemoral and meniscotibial divisions of the deep medial collateral ligament, and the posterior oblique ligament. *Physical examination is the initial method of choice for the diagnosis of medial knee injuries through the application of a valgus load both at full knee extension and between 20 degrees and 30 degrees of knee flexion. *Because nonoperative treatment has a favorable outcome, there is a consensus that it should be the first step in the management of acute isolated grade-III injuries of the medial collateral ligament or such injuries combined with an anterior cruciate ligament tear. *If operative treatment is required, an anatomic repair or reconstruction is recommended.
In a typical osteoarthritic knee with varus deformity, distal femoral resection based off the worn medial femoral condyle may result in an elevated joint line. In a setting of fixed flexion ...contracture, the surgeon may choose to resect additional distal femur to obtain extension, thus purposefully raising the joint line. However, the biomechanical effect of raising the joint line is not well recognized.
(1) What is the effect of the level of the medial joint line (restored versus raised) on coronal plane stability of a TKA? (2) Does coronal alignment technique (mechanical axis versus kinematic technique) affect coronal plane stability of the knee? (3) Can the effect of medial joint-line elevation on coronal plane laxity be predicted by an analytical model?
A TKA prosthesis was implanted in 10 fresh frozen nonarthritic cadaveric knees with restoration of the medial joint line at its original level (TKA0). Coronal plane stability was measured at 0°, 30°, 60°, 90°, and 120° flexion using a navigation system while applying an instrumented 9.8-Nm varus and valgus force moment. The joint line then was raised in two steps by recutting the distal and posterior femur by an extra 2 mm (TKA2) and 4 mm (TKA4), downsizing the femoral component and, respectively, adding a 2- and a 4-mm thicker insert. This was done with meticulous protection of the ligaments to avoid damage. Second, a simplified two-dimensional analytical model of the superficial medial collateral ligament (MCL) length based on a single flexion-extension axis was developed. The effect of raising the joint line on the length of the superficial MCL was simulated.
Despite that at 0° (2.2° ± 1.5° versus 2.3° ± 1.1° versus 2.5° ± 1.1°; p = 0.85) and 90° (7.5° ± 1.9° versus 9.0° ± 3.1° versus 9.0° ± 3.5°; p = 0.66), there was no difference in coronal plane laxity between the TKA0, TKA2, and TKA4 positions, increased laxity at 30° (4.8° ± 1.9° versus 7.9° ± 2.3° versus 10.2° ± 2.0°; p < 0.001) and 60° (5.7° ± 2.7° versus 8.8° ± 2.9° versus 11.3° ± 2.9°; p < 0.001) was observed when the medial joint line was raised 2 and 4 mm. At 30°, this corresponds to an average increase of 64% (3.1°; p < 0.01) in mid-flexion laxity with a 2-mm raised joint line and a 111% (5.4°; p < 0.01) increase with a 4-mm raised joint line compared with the 9-mm baseline resection. No differences in coronal alignment were found between the knees implanted with kinematic alignment versus mechanical alignment at any flexion angle. The analytical model was consistent with the cadaveric findings and showed lengthening of the superficial MCL in mid-flexion.
Despite a well-balanced knee in full extension and at 90° flexion, increased mid-flexion laxity in the coronal plane was evident in the specimens where the joint line was raised.
When recutting the distal and posterior femur and downsizing the femoral component, surgeons should be aware that this action might increase the laxity in mid-flexion, even if the knee is stable at 0° and 90°.
•The “Stener-like” lesion is a distal tear of the MCL with pes anserinus interposition.•Surgical treatment is recommended for the Stener-like lesion.•Knee MRI must include the distal attachment of ...the superficial MCL.•Other ligament injuries can distract from the Stener-like lesion.•Close apposition of torn MCL and pes anserinus may be mistaken for intact MCL.
To describe the MRI findings of the “Stener-like” lesion of the knee and its distinction from simple medial collateral ligament (MCL) tear. A “Stener-like” lesion of the superficial medial collateral ligament is a tear involving the distal fibers, where the torn fibers become displaced superficial to the pes anserinus fibers, a displacement which can prevent healing.
Nine cases of Stener-like lesion were prospectively diagnosed on MRI. Retrospective, IRB-approved, HIPAA-compliant chart review was performed to determine correlation of surgical and MRI findings. Seven cases were surgically confirmed and are included in the series.
MRI is useful in making the diagnosis of Stener-like lesions and prompting the surgeon to explore the distal MCL. Coronal MRI shows variable proximal retraction of the torn ligament. It has a lax contour and abuts the pes anserinus. The proximity of the torn ligament end to the pes can result in misdiagnosis of a partial tear. Axial images are useful to confirm position of the ligament superficial to the pes. All cases had associated tear of the deep MCL fibers, as well as sprains of the proximal superficial MCL.
It is important to recognize the Stener-like lesion because this lesion is usually managed surgically, while most MCL tears are managed conservatively. The presence of injury to the proximal MCL is usually present, and may be a distractor from the distal injury. Care must be taken to include the distal attachment of the sMCL on coronal MRI images.
Medial collateral ligament (MCL) reconstruction (MCLR) is performed after failed nonoperative treatment or high-grade MCL injury with associated valgus instability.
To evaluate clinical outcomes ...after MCLR with autograft versus allograft.
Systematic review, Level of evidence, 4.
A systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The authors conducted a search of the PubMed, CINAHL, EMBASE, and Cochrane databases to identify studies comparing outcomes of MCLR with autograft versus allograft. Studies were included if they evaluated clinical outcomes after MCLR using autograft and/or allograft. Any study that included concomitant knee ligament injury other than the anterior cruciate ligament injury was excluded. A quality assessment was performed using the modified Coleman Methodology Score.
The initial search identified 746 studies, 17 of which met the inclusion criteria and were included in this review. The studies included 307 patients: 151 (49.2%) patients received autografts, and 156 (50.8%) received allografts. The most used autograft was the semitendinosus tendon (136 grafts; 90.1% of specified allografts), and the only allograft used was the Achilles tendon (110 grafts; 100% of specified autografts). The mean follow-up of the studies was 25.6 months. Postoperative pain (Lysholm scores) ranged from 82.9 to 94.8 in patients receiving autografts and 87.5 to 93 in patients receiving allografts. Postoperative range of motion was full in 8 of 15 (53.3%) patients receiving autografts compared with 82 of 93 (88.2%) patients receiving allografts. Five of the 151 (3.3%) patients who had MCLR with autografts had complications such as infection, instability, and prominent screws. Two of the 156 (1.3%) MCLRs with allografts developed complications of prominent screws and nonhealing incisions.
MCLR with either autografts or allografts leads to improved patient-reported, radiographic, and clinical outcomes. Patient-reported postoperative pain was similar in patients receiving either graft type. Other outcomes were difficult to compare between graft types because of nonstandardized reporting and a lack of pre- and postoperative measurements. Therefore, there is no evidence of significantly improved outcomes in the use of either autograft or allograft with MCLR.
Purpose
To define the bony attachments of the medial ligaments relative to anatomical and radiographic bony landmarks, providing information for medial collateral ligament (MCL) surgery.
Method
The ...femoral and tibial attachments of the superficial MCL (sMCL), deep MCL (dMCL) and posterior oblique ligament (POL), plus the medial epicondyle (ME) were defined by radiopaque staples in 22 knees. These were measured radiographically and optically; the precision was calculated and data normalised to the sizes of the condyles. Femoral locations were referenced to the ME and to Blumensaat’s line and the posterior cortex.
Results
The femoral sMCL attachment enveloped the ME, centred 1 mm proximal to it, at 37 ± 2 mm (normalised at 53 ± 2%) posterior to the most-anterior condyle border. The femoral dMCL attachment was 6 mm (8%) distal and 5 mm (7%) posterior to the ME. The femoral POL attachment was 4 mm (5%) proximal and 11 mm (15%) posterior to the ME. The tibial sMCL attachment spread from 42 to 71 mm (81–137% of A-P plateau width) below the tibial plateau. The dMCL fanned out anterodistally to a wide tibial attachment 8 mm below the plateau and between 17 and 39 mm (33–76%) A-P. The POL attached 5 mm below the plateau, posterior to the dMCL. The 95% CI intra-observer was ± 0.6 mm, inter-observer ± 1.3 mm for digitisation. The inter-observer ICC for radiographs was 0.922.
Conclusion
The bone attachments of the medial knee ligaments are located in relation to knee dimensions and osseous landmarks. These data facilitate repairs and reconstructions that can restore physiological laxity and stability patterns across the arc of knee flexion.
Purpose
To evaluate the mid-term outcomes of anatomic medial complex reconstruction in cases of serious medial knee instability.
Methods
Between 2010 and 2013, 23 patients who underwent anatomic ...medial complex reconstruction with a minimum 5-year follow-up were included. The Lysholm score, International Knee Documentation Committee subjective knee form (IKDC SKF), and Tegner activity scale scores were evaluated. Clinical and functional tests included valgus and sagittal stress tests, isokinetic muscle strength test, single leg hop for distance test (SLDT), and single leg vertical jump test (SLVT).
Results
The mean follow-up duration was 77.2 ± 10.8 months. At final follow-up, the Lysholm score improved from 49.7 ± 10.2 to 93.4 ± 12.4; the IKDC SKF score, from 46.2 ± 8.7 to 90.5 ± 13.9; and median Tegner activity, from 5 (4–7) to 7 (4–10) (
P
< 0.001). The mean side-to-side difference on valgus stress radiographs was significantly reduced to 1.2 ± 0.7 mm postoperatively compared to 8.5 ± 1.6 mm preoperatively (
P
< 0.001). The mean side-to-side differences on anterior and posterior stress radiographs were significantly improved in concomitant ACL and PCL reconstructions, respectively (
P
< 0.001). Preoperatively, 17 patients (73.9%) had anteromedial rotatory instability (AMRI), but none had AMRI at the last follow-up. The extensor peak torque and Limb Symmetry Index (LSI, %) improved from 128.2 ± 42.9 to 225 ± 39.4 N m/kg and from 61.4 ± 19.6 to 88.7 ± 21.7%, respectively (
P
< 0.001). The LSI (%) for SLDT and SLVT improved from 56.8 ± 19.5 to 87.3 ± 14.2% and from 68.1 ± 21.1 to 91.1 ± 12.8%, respectively (
P
< 0.001). No patient had a restricted range of movement.
Conclusion
Although posteromedial corner injuries that need medial complex reconstruction are extremely rare, proper anatomic medial complex reconstruction of the medial collateral and posterior oblique ligaments achieved satisfactory clinical and functional outcomes at mid-term follow-up in cases with chronic symptomatic valgus and rotatory laxity.
Level of evidence
Case series, level IV.
Injuries to the medial side of the knee are the most common knee ligament injuries. The majority of injuries occur in young athletes during sporting events, with the usual mechanism involving a ...valgus contact, tibial external rotation, or a combined valgus and external rotation force delivered to the knee. Although most complete grade III medial knee injuries heal, some do not, which can lead to continued instability. For these patients, a thorough understanding of the presenting history and a physical examination are important because these injuries can often be confused with posterolateral corner injuries. The main anatomic structures of the medial side of the knee are the superficial medial collateral ligament, deep medial collateral ligament, and posterior oblique ligament. In addition, accurately locating 3 bony prominences over the medial aspect of the knee-the adductor tubercle, gastrocnemius tubercle, and medial epicondyle-is important to conduct a proper physical examination and for surgical repairs and reconstructions. Clinical diagnosis of medial knee injuries is primarily performed via the application of a valgus stress in full extension and at 30° of knee flexion. In addition, an examination of the amount of anteromedial tibial rotation is performed at 90° of flexion, while the dial test, performed at 30° and 90° of flexion, is important because it evaluates for rotational abnormalities. Valgus stress radiographs are useful to objectively determine the amount of medial compartment gapping and to discern whether there is medial or lateral compartment gapping when a medial or posterolateral corner knee injury cannot be differentiated, especially with a chronic injury. The majority of acute grade III medial knee injuries will heal after a nonoperative rehabilitation program. In most instances when there is a knee dislocation or multiligament injury, a primary repair with sutures may be indicated. In severe midsubstance injuries or chronic medial knee injuries, an anatomic medial knee reconstruction with grafts may be indicated. Rehabilitation principles for acute medial knee injuries involve controlling edema, regaining range of motion, and avoiding any significant stress on the healing ligaments. A well-guided rehabilitation program can result in excellent functional outcomes in the majority of patients.
Medial collateral ligament (MCL) injury is a common sports injury. The damage mainly occurs in ligament fibers, but MCL avulsion fracture is extremely rare and only a few reports have been published.
...Herein, we present a healthy 21-year-old man with an avulsion fracture of the MCL of the right knee sustained during snowboarding.
Clinical and radiographic findings confirmed the presence of an avulsion fracture at the proximal attachment of the MCL, combined with complete anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) rupture.
The patient underwent single-stage ACL, PCL reconstruction, and MCL repair.
Two weeks after the surgery, the patient developed heterotopic ossification (HO) at the medial side of the knee, HO tended to be stable and mature at the 3-month follow-up examination. One year after the operation, the patient's knee was fully functional, stable, and pain free.
Femoral attachment avulsion fracture of the MCL is in contrast to common isolated MCL injuries. Early surgical repair is advocated for the greatest benefit. Orthopedic surgeons should keep the potential complication HO in mind and develop rational strategies for HO prevention and treatment.
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