Surgical anatomy of the medial collateral ligament and the posteromedial capsule of the knee

Isometry of anteromedial reconstructions mimicking the deep medial collateral ligament depends on the femoral insertion

PURPOSE

This study aimed to investigate the length change patterns of the native deep medial collateral ligament (dMCL) and potential anteromedial reconstructions (AMs) that might be added to a reconstruction of the superficial MCL (sMCL) to better understand the control of anteromedial rotatory instability (AMRI).

METHODS

Insertion points of the dMCL and potential AM reconstructions were marked with pins (tibial) and eyelets (femoral) in 11 cadaveric knee specimens. Length changes between the pins and eyelets were then tested using threads in a validated kinematics rig with muscle loading of the quadriceps and iliotibial tract. Between 0° and 100° knee flexion, length change pattern of the anterior, middle and posterior part of the dMCL and simulated AM reconstructions were analysed using a rotary encoder. Isometry was tested using the total strain range (TSR).

RESULTS

The tibiofemoral distance of the anterior dMCL part lengthened with flexion (+12.7% at 100°), whereas the posterior part slackened with flexion (-12.9% at 100°). The middle part behaved almost isometrically (maximum length: +2.8% at 100°). Depending on the femoral position within the sMCL footprint, AM reconstructions resulted in an increase in length as the knee flexed when a more centred position was used, irrespective of the tibial attachment position. Femoral positioning in the posterior aspect of the sMCL footprint exhibited <4% length change and was slightly less tight in flexion (min TSR = 3.6 ± 1.5%), irrespective of the tibial attachment position.

CONCLUSION

The length change behaviour of potential AM reconstructions in a functionally intact knee is mainly influenced by the position of the femoral attachment, with different tibial attachments having a minimal effect on length change. Surgeons performing AM reconstructions to control AMRI would be advised to choose a femoral graft position in the posterior part of the native sMCL attachment to optimise graft length change behaviour. Given the high frequency of MCL injuries, sufficient restoration of AMRI is essential in isolated and combined ligamentous knee injuries.

LEVEL OF EVIDENCE

There is no level of evidence as this study was an experimental laboratory study.

Regional shear wave speeds track regional axial stress in nonuniformly loaded fibrous soft tissues

Ligaments and tendons undergo nonuniform deformation during movement. While deformations can be imaged, it remains challenging to use such information to infer regional tissue loading. Shear wave tensiometry is a promising noninvasive technique to gauge axial stress and is premised on a tensioned beam model. However, it is unknown whether tensiometry can predict regional stress in a nonuniformly loaded structure. The objectives of this study were to (1) determine whether regional shear wave speed tracks regional axial stress in nonuniformly loaded fibrous soft tissues, and (2) determine the sensitivity of regional axial stress and shear wave speed to nonuniform load distribution and fiber alignment. We created a representative set of 12,000 dynamic finite element models of a fibrous soft tissue with probabilistic variations in fiber alignment, stiffness, and aspect ratio. In each model, we applied a randomly selected nonuniform load distribution, and then excited a shear wave and tracked its regional propagation. We found that regional shear wave speed was an excellent predictor of the regional axial stress (RMSE = 0.57 MPa) and that the nature of the regional shear wave speed-stress relationship was consistent with a tensioned beam model (R2 = 0.99). Variations in nonuniform load distribution and fiber alignment did not substantially alter the wave speed-stress relationship, particularly at higher loads. Thus, these findings suggests that shear wave tensiometry could provide a quantitative estimate of regional tissue stress in ligaments and tendons.

Mesenchymal Stem Cells for Enhanced Healing of the Medial Collateral Ligament of the Knee Joint

Background and Objectives: The medial collateral ligament (MCL) is one of the major supporting ligaments of the knee joint, and MCL injuries are common where excessive valgus loading is applied to the knee joint. Although most MCL injuries can be treated conservatively, healing of the MCL can take several weeks to months. Furthermore, once injured, the biomechanical properties of the healed MCL differ from those of the native MCL, resulting in an increased risk of re-injury and chronic remnant symptoms. Mesenchymal stem cells (MSCs), owing to their therapeutic potential, have been investigated in various musculoskeletal injuries, and some preclinical studies regarding MSC-based approaches in MCL injuries have shown promising results. Despite satisfactory results in preclinical studies, there is still a lack of clinical studies in the orthopedic literature. This article describes the basic knowledge of the MCL, standard treatments for MCL injuries, and recent studies regarding the application of MSCs for enhanced healing of the MCL. MSC-based approaches are expected to be a potential therapeutic option for enhanced healing of the MCL in the future.

Comparative study of superficial medial collateral ligament reconstruction combined with posterior oblique ligament reconstruction or posteromedial capsule advance in grade III injuries of the medial compartment in a complex knee injury scenario

BACKGROUND

The purpose of this study was to compare the combined reconstruction of the superficial medial collateral ligament (sMCL) and the posterior oblique ligament (POL) with the reconstruction of the sMCL associated with the advancement of the posteromedial capsule in a complex knee injury scenario. We hypothesized that both techniques would present similar knee stability and failure rates.

METHODS

This is a retrospective case-control study designed to compare the results of the two reported techniques for grade III MCL instability. Patients undergoing MCL reconstruction associated with anterior cruciate ligament, posterior cruciate ligament, or both, from 2010 to 2019, were included. The following parameters were evaluated: demographic data, type of graft, time from injury to surgery, associated meniscus injuries, follow up time, mechanism of trauma, postoperative objective IKDC, subjective IKDC and Lysholm scales, range of motion, reconstruction failure and complications.

RESULTS

Seventy-eight patients were evaluated, 37 of whom underwent reconstruction of the sMCL and POL, and 41 of whom underwent reconstruction of the sMCL with advancement of posteromedial structures. There was no difference in any preoperative variable. Patients undergoing reconstruction of the sMCL + advancement had greater loss of flexion (Group 1 3.4 ± 4.6 vs Group 2 8.4 ± 7.9; P = 0.002) and more individuals with flexion loss greater than 10° (Group 1, seven patients (18.9%) vs Group 2, 17 patients (41.5%); P = 0.031). Postoperative knee stability, failures and complications were similar between groups.

CONCLUSION

Both techniques presented good functional results and low rates of complications. However, the advancement technique showed greater flexion loss, which should be considered when choosing the best surgical option.

Does Transection of the Superficial MCL During HTO Result in Progressive Valgus Instability? [Formula: see text]

BACKGROUND

During high tibial osteotomy (HTO), the superficial medial collateral ligament (sMCL) is cut or released at any degree to expose the osteotomy site and achieve the targeted alignment correction according to the surgeon's preference. However, it is still unclear whether transection of sMCL increases valgus laxity.

PURPOSE

We aimed to assess the outcomes and safety of sMCL transection, especially focusing on iatrogenic valgus instability.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Seventy-two patients (89 knees) who underwent medial open wedge HTO (MOWHTO) with transection of the sMCL between October 2013 and September 2018 were retrospectively investigated. Clinical evaluations, including the International Knee Documentation Committee (IKDC) score, Knee injury and Osteoarthritis Outcome Score (KOOS), and Tegner and Lysholm scores, were performed preoperatively and at 2 years postoperatively. The radiographic parameters hip-knee-ankle (HKA) angle, joint line convergence angle on standing radiographs (standing JLCA), and weightbearing line (WBL) ratio were assessed preoperatively and at 3 months, 6 months, 1 year, and 2 years postoperatively. To evaluate valgus laxity, we assessed the valgus JLCA and medial joint opening (MJO) at the aforementioned time points using valgus stress radiographs.

RESULTS

All clinical results at the 2-year follow-up were significantly improved compared with those obtained at the preoperative assessment (P < .001). The postoperative HKA angle significantly differed from the preoperative one, and no significant valgus progression was observed during follow-up (preoperative, 8.5°± 2.7°; 3 months, -3.5°± 2.0°; 6 months, -3.2°± 2.3°; 1 year, -3.1°± 2.3°; 2 years, -2.9°± 2.5°; P < .001) The mean WBL ratio was 62.5% ± 9.0% at 2 years postoperatively. The postoperative valgus JLCA at all follow-up points did not significantly change compared with the preoperative valgus JLCA (preoperative, -0.1°± 2.1°; 3 months, -0.2°± 2.4°; 6 months, -0.1°± 2.5°; 1 year, 0.1°± 2.5°; 2 years, 0.2°± 2.2°) The postoperative MJO at all follow-up points did not significantly change compared with the preoperative MJO (preoperative, 7.1 ± 1.7 mm; 3 months, 7.0 ± 1.7 mm; 6 months, 6.9 ± 1.9 mm; 1 year, 6.7 ± 1.8 mm; 2 years, 6.8 ± 1.8 mm).

CONCLUSION

Transection of the sMCL during MOWHTO does not increase valgus laxity and could yield desirable clinical and radiographic results.

Semimembranosus Tendon Advancement for the Anteromedial Knee Rotatory Instability Treatment

Injury to the medial compartment of the knee is the most common ligament injury to this joint. The medial approach must consider the presence of associated anteromedial instability. Untreated injury of these instabilities can result in failure of the other reconstructed ligaments. As treatment is usually associated with other ligaments, it is relevant that the technique could save grafts and synthetic material. This article aims to describe a technique for the treatment of anteromedial instabilities through semimembranosus tendon tenodesis in a more anterior and distal position, promoting the tensioning of the posteromedial structures.

Impact of intraoperative medial collateral ligament injury on outcomes after total knee arthroplasty: a meta-analysis and systematic review

BACKGROUND

As an uncommon but severe complication, medial collateral ligament (MCL) injury in total knee arthroplasty (TKA) may be significantly under-recognized. We aimed to determine whether MCL injury influences postoperative outcomes of patients undergoing TKA.

METHODS

Two independent reviewers searched PubMed, Cochrane Library, and EMBASE from their inception to July 1, 2021. The main outcomes were postoperative function, and secondary outcomes included the incidences of revision and complications.

RESULTS

A total of 403 articles yielded 15 studies eligible for inclusion with 10 studies used for meta-analysis. This study found that there was a statistically significant difference in postoperative functional scores, range of motion (ROM), complications, and revision rates, with adverse outcomes occurring more commonly in patients with MCL injury.

CONCLUSIONS

This meta-analysis highlights the complexity of MCL injury during TKA and shows the impact on postoperative function, joint mobility, complications, and revision. Surgeons need to prevent and put more emphasis on MCL injury during TKA.

Medial soft-tissue complex of the knee: Current concepts, controversies, and future directions of the forgotten unit

The medial side of the knee is comprised of ligaments, myotendinous and meniscal structures that work as a unit to stabilize the joint. The superficial medial collateral ligament is its core structure. Still, all elements of the medial side have load-sharing relationships, leading to a cascade of events in the scenario of insufficiency of any of them. Understanding the medial soft tissue structures as part of a unit is of utmost importance because the most common ligaments damaged in knee injuries belong to it. Surprisingly, there is a lack of high-level evidence published around the issue, and most studies focus on the superficial medial collateral ligament, overlooking the complexity of these injuries. Acknowledging the consequences for joint biomechanics and treatment outcomes, interest in this area is growing between researchers. Emerging evidence may become a game-changer in the future management of these injuries. Based on a thorough research of published literature, this review provides a current biomechanical concepts and clinical guidance to treat these injuries.

Joint distraction force changes the three-dimensional articulation of the femur and tibia in total knee arthroplasty: a cadaveric study

PURPOSE

The purpose of this study was to test the hypotheses that the joint distraction force changes the three-dimensional articulation between the femur and the tibia and that the presence of posterior cruciate ligament (PCL) affects the three-dimensional articulation during joint gap evaluation in total knee arthroplasty (TKA).

METHODS

Cruciate-retaining TKA procedures were performed on 6 cadaveric knees using a navigation system. The joint center gap and varus ligament balance were measured using Offset Repo-Tensor^® with the knee at 90° of flexion before and after PCL resection for joint distraction forces of 89, 178, and 266 N. The three-dimensional location of the tibia relative to the femur and the axial rotational angle of the tibia were also assessed.

RESULTS

Regardless of PCL resection, the joint center gap became larger (p = 0.002, p = 0.020) and varus ligament balance became more varus (p = 0.002, p = 0.002) with increasing joint distraction force, whereas the tibia was more internally rotated (p = 0.015, p = 0.009) and more anteriorly located (p = 0.004, p = 0.009). The tibia was more internally rotated (p = 0.015) and more posteriorly located (p = 0.026) after PCL resection than before resection.

CONCLUSIONS

Joint distraction force changed three-dimensional articulation regardless of PCL preservation. PCL function was revealed as a factor restraining both tibial posterior translation and internal rotation. Surgeons should recognize that joint gap evaluation using a tensor device is subject to three-dimensional changes depending on the magnitude of the joint distraction force.

The bone attachments of the medial collateral and posterior oblique ligaments are defined anatomically and radiographically

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.

Operative Treatment for a Painful Nonunion Avulsion Fracture of the Femoral Attachment of the Medial Collateral Ligament in a Teenager: A Case Report

CASE

A 13-year-old female gymnast presented with medial knee pain despite several months of nonoperative management for a valgus hyperextension injury resulting in a bony avulsion fracture of the medial collateral ligament (MCL) origin at the medial femoral condyle. The MCL was repaired via open reduction and internal fixation (ORIF) with a single 4.0 mm cannulated screw and washer.

CONCLUSIONS

ORIF is a successful treatment option for extra-articular bony MCL origin avulsion fractures that fail conservative treatment. Following surgical intervention and structured physical therapy, our patient had full return to sports at 10 months.

Medial collateral ligament laxity in valgus knee deformity before and after medial closing wedge high tibial osteotomy measured with instrumented laxity measurements and patient reported outcome

INTRODUCTION

Medial closing wedge high tibial osteotomy (CWHTO) for valgus deformity correction was first described by Coventry whom performed an additional reefing of the medial collateral ligament (MCL) to prevent instability postoperative. In our clinic the additional reefing procedure has never been performed and instability has not been reported routinely by patients. Using instrumented laxity testing, pre- and postoperative valgus and varus knee laxity can be measured objectively. We hypothesize that absence of changes in laxity testing and subjective knee stability scores support that no additional reefing procedure is necessary.

MATERIALS AND METHODS

In a prospective cohort study 11 consecutive patients indicated for medial CWHTO were subjected to pre- and postoperative stress X-rays in 30° and 70° of flexion and opening of the joint line was measured in degrees on the radiographs. Patient reported outcome scores were documented with the KOOS, Lysholm, SF36, Oxford Knee Score and a VAS instability scoring tool.

RESULTS

All patients (7 females) completed the study, mean age was 46 years. Mean preoperative Hip Knee Ankle angle 6.4° valgus was corrected to mean postoperative alignment 0.1° valgus. A significant difference was measured between mean pre- and postoperative 30° valgus laxity (2.8° vs 5.3°, P = 0.005), 30° varus laxity (6.7° vs 3.2°, P = 0.005) and 70° valgus laxity (2.0° vs 4.8°, P = 0.008). Postoperative patient-reported knee instability as measured with the Lysholm questionnaire was significantly improved compared to preoperative instability (P = 0.006). VAS instability improved, but didn't reach significance (8.0 preoperative and 5.5 postoperative (P = 0.127). Other outcome measures showed improvement as well. No correlations between radiological findings and outcome scores were found.

CONCLUSION

A significant increase in postoperative valgus laxity in 30° and 70° of flexion deems reconsidering addition of MCL reefingplasty to the medial CWHTO although patient reported outcome on subjective stability scores fails to report increase of instability in this study population. Instrumented laxity measurements of medial CWHTO patients treated with additional medial reefingplasty should be performed to prove the value of this procedure.

Association of Medial Meniscus Extrusion With the Prominence of a Fascicular Capsulofemoral Band Subjacent to the Deep Medial Collateral Ligament

OBJECTIVE

The objective of our study was to test our hypothesis that a transverse oblique fascicular anteromedial capsulofemoral band partially subjacent to the deep medial collateral ligament (MCL) is more prominent in knees with medial meniscal extrusion.

MATERIALS AND METHODS

We retrospectively analyzed all knee MRI examinations from a 6-month period for the presence and dimensions of the anteromedial capsulofemoral band on coronal proton-density fat-saturated images and also for medial meniscus extrusion, which was defined as extrusion of 3 mm or greater. Edemalike signal intensity within or in the vicinity of the anteromedial capsulofemoral band, partial or complete tears of the MCL, a history of MCL surgery, or a neoplastic mass lesion violating the medial supporting structures were exclusion criteria. We reviewed procedural videos of patients who subsequently underwent knee arthroscopy. MRI of a cadaveric knee was performed and was followed by dissection and histologic examination.

RESULTS

MRI examinations of 346 knees of 312 patients met the inclusion criteria; of these knees, 50 had medial meniscus extrusion. The anteromedial capsulofemoral band was discernible on MRI in all knees except five (98.6%), and it was visible in six of the arthroscopy videos of 17 knees. The anteromedial capsulofemoral band was thicker on MRI of patients with medial meniscus extrusion (p < 0.0001). The anteromedial capsulofemoral band was identified on MRI and at dissection of the cadaveric knee, and histologic examination revealed that the anteromedial capsulofemoral band was a capsuloligamentous structure.

CONCLUSION

A transverse oblique anteromedial capsulofemoral band subjacent to the deep MCL is thicker in knees with medial meniscus extrusion.

Mapping of contributions from collateral ligaments to overall knee joint constraint: an experimental cadaveric study

Understanding the contribution of the soft-tissues to total joint constraint (TJC) is important for predicting joint kinematics, developing surgical procedures, and increasing accuracy of computational models. Previous studies on the collateral ligaments have focused on quantifying strain and tension properties under discrete loads or kinematic paths; however, there has been little work to quantify collateral ligament contribution over a broad range of applied loads and range of motion (ROM) in passive constraint. To accomplish this, passive envelopes were collected from nine cadaveric knees instrumented with implantable pressure transducers (IPT) in the collateral ligaments. The contributions from medial and lateral collateral ligaments (LCL) were quantified by the relative contribution of each structure at various flexion angles (0-120 deg) and compound external loads (±10 N m valgus, ±8 N m external, and ±40 N anterior). Average medial collateral ligament (MCL) contributions were highest under external and valgus torques from 60 deg to 120 deg flexion. The MCL showed significant contributions to TJC under external torques throughout the flexion range. Average LCL contributions were highest from 0 deg to 60 deg flexion under external and varus torques, as well as internal torques from 60 deg to 110 deg flexion. Similarly, these regions were found to have statistically significant LCL contributions. Anterior and posterior loads generally reduced collateral contribution to TJC; however, posterior loads further reduced MCL contribution, while anterior loads further reduced LCL contribution. These results provide insight to the functional role of the collaterals over a broad range of passive constraint. Developing a map of collateral ligament contribution to TJC may be used to identify the effects of injury or surgical intervention on soft-tissue, and how collateral ligament contributions to constraint correlate with activities of daily living.

Medial meniscus anatomy-from basic science to treatment

This paper focuses on the anatomical attachment of the medial meniscus. Detailed anatomical dissections have been performed and illustrated. Five zones can be distinguished in regard to the meniscus attachments anatomy: zone 1 (of the anterior root), zone 2 (anteromedial zone), zone 3 (the medial zone), zone 4 (the posterior zone) and the zone 5 (of the posterior root). The understanding of the meniscal anatomy is especially crucial for meniscus repair but also for correct fixation of the anterior and posterior horn of the medial meniscus.

Clinical features and injury patterns of medial collateral ligament tibial side avulsions: "wave sign" on magnetic resonance imaging is essential for diagnosis

BACKGROUND

Medial collateral ligament tibial avulsion is rare. Consequently, diagnostic criteria and a treatment regimen for medial collateral ligament tibial side avulsions remain to be established. The purpose of this study is to clarify the clinical features of medial collateral ligament tibial side avulsions.

METHODS

We performed a retrospective clinical and magnetic resonance imaging review of a consecutive series of 12 medial collateral ligament tibial side avulsions. All patients were treated operatively and the final diagnosis was made based on the intraoperative findings. Post-injury magnetic resonance imaging studies were reviewed to assess injury patterns with respect to the intraoperative findings.

RESULTS

Eleven of 12 cases (92%) had grade III valgus laxity (unstable to valgus stress at both 0° and 30° of flexion) on an examination under anesthesia. Concomitant anterior cruciate ligament tear was noticed in all cases. Intraoperative findings were classified into 3 types depending on the location of the ruptured end of the superficial medial collateral ligament with respect to the pes anserinus tendons. Magnetic resonance imaging depicted characteristic waving ("wave sign") of the superficial layer of medial collateral ligament in all cases.

CONCLUSIONS

"Wave sign" of the superficial layer of medial collateral ligament on magnetic resonance imaging is essential for diagnosing medial collateral ligament tibial side avulsions. Based on the clinical features and injury patterns, operative treatment is primarily recommended for medial collateral ligament tibial side avulsions.

LEVEL OF EVIDENCE

Case series, Level IV.

Consideration of growth factors and bio-scaffolds for treatment of combined grade II MCL and ACL injury

The literature suggests that a Grade II medial collateral ligament (MCL) injury in combination with anterior cruciate ligament (ACL) injury will heal naturally and not compromise patient outcome following ACL reconstruction. Evidence based on bone-patella tendon-bone autograft use is stronger than evidence supporting anatomically placed soft tissue graft use. Current ACL reconstruction practices make greater use of soft tissue grafts, differing fixation methods, and anatomically lower placement on the inner wall of the lateral femoral condyle. Anatomical graft placement aligns the femoral bone tunnel more directly with valgus knee loading forces. Differences in the soft tissue graft-bone tunnel integration and ligamentization timetable following ACL reconstruction also increase concerns regarding residual Grade II MCL laxity and functional deficiency during accelerated functional rehabilitation. MCL dysfunction may increase susceptibility to early ACL graft slippage, elongation, outright failure, and medial femoral condyle lift-off with valgus knee loading. This concept paper discusses the potential role of growth factors and bio-scaffolds for improving Grade II MCL injury healing and mechanical integrity when the injury occurs in combination with an ACL injury that is reconstructed with a soft tissue graft and an anatomical surgical approach.

Repair of medial collateral ligament injury during total knee arthoplasty

Intraoperative midsubstance lacerations of the medial collateral ligament (MCL) must be addressed during surgery, and failure to obtain coronal plane stability could affect patient outcomes and satisfaction. This article reports our results of a series of patients who sustained an intraoperative MCL injury during a primary total knee arthroplasty and were treated by direct primary repair and no change in implant constraint or postoperative protocol. Over a 5-year period, 9 patients sustained this complication. We reviewed their subjective satisfaction and stability, as well as objective measures such as functional scores, physical examinations, and radiographs. Average patient age was 58 years, and mean patient body mass index was 43.3. All patients were satisfied with the procedure and demonstrated no instability on physical examination. Average Knee Society pain score was 91.5 and functional score was 73.3. No radiographic changes or signs of loosening were noted. This novel approach for intraoperative midsubstance lacerations of the MCL does not involve altering implants or postoperative protocols and has encouraging results.

Case report of atypical bilateral posteromedial knee instability in a male recreational runner

The posteromedial corner of the knee has intricate anatomical and biomechanical relationships critical to the function of the tibiofemoral joint. Missed or late diagnosis of pathomechanical disorders of the region, such as anteromedial rotary instability, in individuals with knee pain, may result in long-term decreased functional mobility and predisposition for degenerative disorders. This case report describes the chronological history and experience of a 35-year-old male with late diagnosis of anteromedial rotary instability and the subsequent surgical reconstruction and rehabilitation. Difficulties with clinical recognition of the underlying pathology and the postoperative course of rehabilitation are also discussed.

Management of medial collateral ligament injuries in the knee: an update and review

The medial collateral ligament (MCL) is the most frequently injured ligament in the knee, with mild-to-moderate tears often going unreported to physicians. Medial collateral ligament injuries can result from both contact and noncontact sporting activities. The mainstay of treatment is nonoperative; however, operative management of symptomatic grade II and grade III injuries is considered when laxity and instability persist. The timing of surgical repair in the setting of a multiligament knee injury remains an area of controversy among surgeons, with proponents of early reconstruction of the anterior and posterior cruciate ligaments and nonoperative management of the MCL versus proponents of delayed reconstruction following nonoperative treatment of the MCL. Prophylactic bracing may continue to increase and evolve as bracing technology improves and athletic cultures change.

Ligament releases do not lead to increased postoperative varus-valgus laxity in flexion and extension: a prospective clinical study in 49 TKR patients

This prospective study investigated whether ligament releases necessary during total knee replacement (TKR) led to a higher varus-valgus laxity during intraoperative examination after implantation of the prosthesis and after 6 months. The laxity values of TKR patients were also compared to healthy controls. Varus-valgus laxity was assessed intra- and postoperatively in extension and 70 degrees flexion in 49 patients undergoing TKR, implanted using a balanced gap technique. Knees were catalogued according to ligament releases performed during surgery. Postoperative varus-valgus laxity and laxity after 6 months had not increased following release of the posteromedial capsule, iliotibial tract, and the superficial medial collateral ligament. The obtained postoperative laxity compares well with a healthy equally aged control group. It can be concluded that the balanced gap technique results in stable knees and that releases can safely be performed to achieve neutral leg alignment without causing postoperative laxity.

Congenital absence of the semimembranosus muscle: case report

Congenital anomalies of the muscles of the lower extremity are rare. A case of complete absence of the semimembranosus muscle incidentally found with magnetic resonance imaging is reported. The patient was a 55-year-old female presenting with knee pain and no previous history of trauma. Clinical and imaging findings were consistent with meniscal tears. Two cases of uncommon distal insertion of the semimembranosus tendon are also described to illustrate the anatomical variations in this area. The anatomical and biomechanical relations between the semimembranosus muscle and the posteromedial corner of the knee are examined in this case report.

Medial knee injury: Part 2, load sharing between the posterior oblique ligament and superficial medial collateral ligament

BACKGROUND

There is limited information regarding directly measured load responses of the posterior oblique and superficial medial collateral ligaments in isolated and multiple medial knee ligament injury states.

HYPOTHESES

Tensile load responses from both the superficial medial collateral ligament and the posterior oblique ligament would be measurable and reproducible, and the native load-sharing relationships between these ligaments would be altered after sectioning of medial knee structures.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twenty-four nonpaired, fresh-frozen adult cadaveric knees were distributed into 3 sequential sectioning sequences. Buckle transducers were applied to the posterior oblique ligament and the proximal and distal divisions of the superficial medial collateral ligament; 10 N.m valgus moments and 5 N.m internal and external rotation torques were applied at 0 degrees , 20 degrees , 30 degrees , 60 degrees , and 90 degrees of knee flexion.

RESULTS

With an applied valgus and external rotation moment, there was a significant load increase on the posterior oblique ligament compared with the intact state after sectioning all other medial knee structures. With an applied external rotation torque, there was a significant load decrease on the proximal division of the superficial medial collateral ligament from the intact state after sectioning all other medial knee structures. With an applied external rotation torque, the distal division of the superficial medial collateral ligament experienced a significant load increase from the intact state after sectioning the posterior oblique ligament and the meniscofemoral division of the deep medial collateral ligament.

CONCLUSION

This study found alterations in the native load-sharing relationships of the medial knee structures after injury. Sectioning both the primary and secondary restraints to valgus and internal/external rotation of the knee alters the intricate load-sharing relationships that exist between the medial knee structures.

CLINICAL SIGNIFICANCE

In cases in which surgical repair or reconstruction is indicated, consideration should be placed on repairing or reconstructing all injured medial knee structures to restore the native load-sharing relationships among these medial knee structures.

Radiographic identification of the primary medial knee structures

BACKGROUND

Radiographic landmarks for medial knee attachment sites during anatomic repairs or reconstructions are unknown. If identified, they could assist in the preoperative evaluation of structure location and allow for postoperative assessment of reconstruction tunnel placement.

METHODS

Radiopaque markers were implanted into the femoral and tibial attachments of the superficial medial collateral ligament and the femoral attachments of the posterior oblique and medial patellofemoral ligaments of eleven fresh-frozen, nonpaired cadaveric knee specimens. Both anteroposterior and lateral radiographs were made. Structures were assessed within quadrants formed by the intersection of reference lines projected on the lateral radiographs. Quantitative measurements were performed by three independent examiners. Intraobserver reproducibility and interobserver reliability were determined with use of intraclass correlation coefficients.

RESULTS

The overall intraclass correlation coefficients for intraobserver reproducibility and interobserver reliability were 0.996 and 0.994, respectively. On the anteroposterior radiographs, the attachment sites of the superficial medial collateral ligament, posterior oblique ligament, and medial patellofemoral ligament were 30.5 +/- 2.4 mm, 34.8 +/- 2.7 mm, and 42.3 +/- 2.1 mm from the femoral joint line, respectively. On the lateral femoral radiographs, the attachment of the superficial medial collateral ligament was 6.0 +/- 0.8 mm from the medial epicondyle and was located in the anterodistal quadrant. The attachment of the posterior oblique ligament was 7.7 +/- 1.9 mm from the gastrocnemius tubercle and was located in the posterodistal quadrant. The attachment of the medial patellofemoral ligament was 8.9 +/- 2.0 mm from the adductor tubercle and was located in the anteroproximal quadrant. On the lateral tibial radiographs, the proximal and distal tibial attachments of the superficial medial collateral ligament were 15.9 +/- 5.2 and 66.1 +/- 3.6 mm distal to the tibial inclination, respectively.

CONCLUSIONS

The attachment locations of the main medial knee structures can be qualitatively and quantitatively correlated to osseous landmarks and projected radiographic lines, with close agreement among examiners.

Treatment of medial collateral ligament injuries

The medial collateral ligament is the most frequently injured ligament of the knee. The anatomy and biomechanical role of this ligament and the associated posteromedial structures of the knee continue to be explored. Prophylactic knee bracing has shown promise in preventing injury to the medial collateral ligament, although perhaps at the cost of functional performance. Most isolated injuries are treated nonsurgically. Recent studies have investigated ligament-healing variables, including modalities such as ultrasound and nonsteroidal anti-inflammatory drugs. Concomitant damage to the anterior or posterior cruciate ligaments is a common indication to surgically address the high-grade medial collateral ligament injury. The optimal treatment of multiligamentous knee injuries continues to evolve, and controversy exists surrounding the role of medial collateral ligament repair/reconstruction, with data supporting both conservative and surgical management.

Persistent symptoms following non operative management in low grade MCL injury of the knee - The role of the deep MCL

Incomplete injuries (grade I or II) to the medial collateral ligament (MCL) of the knee are common and usually self limiting. Some patients complain of chronic medial knee pain following injury. We highlight the importance of anatomical investigation of these patients and evaluate a successful treatment technique. A consecutive case series of 34 patients with chronic pain following grade I/II MCL injury were reviewed. Injury prevented sporting activity, and examination revealed thickening and tenderness of the MCL. The knee was assessed by MRI. All patients had radiological evidence of injury to the superficial and deep MCL, with thickening, scarring and tearing. Patients were treated with ultrasound guided injection of local anaesthetic and steroid into the deep MCL and clinically reassessed. They were allowed to return to sport immediately. They were assessed for recurrence of symptoms with a postal questionnaire. Four were excluded from follow up. Four were lost. All patients reported an immediate and sustained resolution their medial knee pain. At mean follow up of 20.4 months (range 11-38 months) all were back to their pre-injury level of work. Twenty five (96%) had immediate and sustained return to sporting activity. Twenty one (81%) reported no change in level of sporting function. In patients with persistent medial joint pain following grade I/II MCL sprain, pain from the deep MCL must be considered. MRI will confirm the diagnosis, exclude coexistent pathology and localise the lesion within the deep MCL. A single corticosteroid injection provides an excellent clinical outcome 20 months post injection.

The role of the posterior oblique ligament in controlling posterior tibial translation in the posterior cruciate ligament-deficient knee

BACKGROUND

Posterior cruciate ligament injuries are often associated with injuries to other structures. The role of the posteromedial structures of the knee in these injuries has received little attention.

HYPOTHESIS

The posterior oblique ligament is an important restraint to posterior tibial translation in the posterior cruciate ligament-deficient knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Kinematic studies were performed on 10 cadaveric knees to test 3 external loading conditions at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion (134 N posterior tibial load, 10 N x m valgus rotation, and 5 N x m internal rotation). Resulting posterior tibial translation was determined by using a robotic/universal force-moment sensor testing system for (1) intact, (2) posterior cruciate ligament-deficient, (3) posterior cruciate ligament/superficial medial collateral ligament-deficient, (4) posterior cruciate ligament/superficial medial collateral ligament/deep medial collateral ligament/posterior oblique ligament-deficient, and (5) posterior cruciate ligament/superficial medial collateral ligament/deep medial collateral ligament/posterior oblique ligament/posteromedial capsule-deficient knee.

RESULTS

When both the superficial medial collateral ligament and deep medial collateral ligament were cut in the posterior cruciate ligament-deficient knee, posterior tibial translation did not increase significantly at any flexion grade under all external loading conditions (P > .05). Additional cutting of the posterior oblique ligament increased posterior tibial translation significantly at 0 degrees , 30 degrees , 60 degrees , and 90 degrees of flexion under posterior tibial load and at all flexion angles tested under valgus or internal tibial load (P < .05). Additional cutting of the posteromedial capsule increased posterior tibial translation only at 0 degrees and 30 degrees in response to a valgus and internal tibial load (P < .05).

CONCLUSION

The posterior oblique ligament and posteromedial capsule have a significant role in the prevention of additional posterior tibial translation in the knee with posterior cruciate ligament injury.

CLINICAL RELEVANCE

The posterior oblique ligament should be addressed in the patient with combined injuries to the posterior cruciate ligament and the posteromedial structures.

Bänder des Kniegelenks

The ligaments of the knee can be divided into four groups. Ventral reinforcements are the patellar retinaculae. The posteromedial complex stabilizes the valgus stress. It consists of the medial collateral ligament, the thickened posteromedial capsule and a branch of the tendon of the semimembranosus muscle as well as the oblique popliteal ligament. On the lateral side the posterolateral complex protects the knee against varus stress. Here the lateral collateral ligament, the tendon of the popliteus muscle and the so-called popliteofibular fibres work together. The cruciate ligaments control the contact between femoral condyles and tibial plateau during flexion-extension of the knee. They course between the two layers of the capsule, the membranous and the synovial layer.

Morphologic study of the lateral and medial collateral ligaments of the human knee

The collateral ligaments of the knee are important in maintaining knee stability. Numerous studies have been described the morphology and function of the ligaments of the knee. However, little data was given about the lateral and medial collateral ligaments simultaneously. The objective of the present study was to compare the morphology of the lateral (LCL) and medial (MCL) collateral ligaments in human knees. We dissected 34 cadaver knees and examined the size, attachment and inclination of the LCL and the MCL. In both of them, the posterior bundle was longer than that of the anterior bundle. The anterior and posterior bundles of the MCL were longer than that of the LCL. The proximal attachment of the MCL situated more anterior and superior than that of the LCL. As compared with the LCL, the distal attachment of the MCL located a little forward and inferior. The longitudinal diameter of the attachment of ligaments was longer than the transverse one, except for the proximal attachment of the MCL. The size of the attachments of the MCL was larger than that of the LCL except for the longitudinal diameter of the proximal attachment. At full extension of the knee, the inclination of the MCL was backward, while that of the LCL was forward. These data showed that the LCL and MCL had the different structural properties. It may provide a better understanding of the function of the collateral ligaments.

The effect of anterior cruciate ligament deficiency on the in vivo elongation of the medial and lateral collateral ligaments

BACKGROUND

Although anterior cruciate ligament deficiency has been shown to lead to joint degeneration, few quantitative data have been reported on its effect on soft tissue structures surrounding the knee joint.

HYPOTHESIS

Anterior cruciate ligament deficiency will alter the deformation of both collateral ligaments during in vivo weight-bearing knee function from 0 degrees to 90 degrees.

STUDY DESIGN

Controlled laboratory study.

METHODS

Six patients who had acute anterior cruciate ligament injury in 1 knee with the contralateral side intact participated in this study. Using magnetic resonance and dual orthogonal fluoroscopic imaging techniques, we measured the length of the fiber bundles of the superficial medial collateral ligament, deep medial collateral ligament, and lateral collateral ligament of the 6 patients; the healthy contralateral knee of each patient served as a control.

RESULTS

Anterior cruciate ligament injury caused a significant elongation of the fiber bundles of the superficial and deep medial collateral ligament at every flexion angle. In contrast, the lateral collateral ligament fiber bundles shortened after anterior cruciate ligament injury.

CONCLUSION

The altered deformations of the collateral ligaments associated with the changes in tibiofemoral joint kinematics after anterior cruciate ligament injury demonstrate that deficiency of 1 of the knee joint structures upsets the in vivo knee homeostasis.

CLINICAL RELEVANCE

Restoring normal knee kinematics after anterior cruciate ligament reconstruction is critical to restore the normal function of the collateral ligaments.