Medial Collateral Ligament Reconstruction: A Gracilis Tenodesis for Anteromedial Knee Instability

Optimizing the Control of Anteromedial Rotatory Knee Instability: A Biomechanical Validation of Different Anteromedial Reconstruction Techniques

BACKGROUND

Anteromedial rotatory instability (AMRI) can result from combined injury to the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) complex (superficial and deep [sMCL and dMCL]).

HYPOTHESIS

Adding an oblique anteromedial (AM) limb to an sMCL reconstruction improves the control of AMRI.

STUDY DESIGN

Controlled laboratory study.

METHODS

A 6 degrees of freedom robotic setup simulated clinical laxity in 9 unpaired knees under the following tests: 5-N·m external rotation (ER), 8-N·m valgus rotation (VR), and AM drawer (combined 89-N anterior tibial translation and 5-N·m ER). Knees were tested intact after cutting the sMCL and dMCL and after 5 different reconstructions: modified Lind, short sMCL, and sMCL with the addition of an AM graft limb with 3 different obliquities.

RESULTS

After short sMCL reconstruction, AM drawer and ER laxity were not significantly different from either the MCL-deficient state or the intact state. VR was reduced from the MCL-deficient state between 0° and 60° of flexion but not at 90°. For combined sMCL + AM reconstructions, VR was reduced as compared with the MCL-deficient state at all flexion angles. AM drawer laxity and ER laxity were also reduced, similar to the intact state, except at 30° where, for the more oblique T1 and T2 AM reconstructions, laxity was less than in the intact state. The modified Lind reconstruction reduced AM drawer and ER laxity from the MCL-deficient state to values similar to the intact state at all flexion angles. VR laxity was also reduced at all flexion angles, similar to the intact knee at 0° to 30°. However, it was not as good at restraining AM drawer and ER when compared with the sMCL reconstructions with more oblique AM limbs.

CONCLUSION

AMRI appears to be better restrained by adding an oblique AM graft limb to an sMCL reconstruction, replicating the function of the sMCL and dMCL in a cadaveric model. The tibial attachment of the AM limb should be anterior to the sMCL, but its precise attachment on the tibia is less important. This offers surgical flexibility, which may be helpful in avoiding anterior cruciate ligament tibial tunnel coalition. The femoral attachment on the posterior medial epicondyle is critical to optimize graft isometry.

CLINICAL RELEVANCE

Adding an AM limb to a medial reconstruction optimizes the control of AMRI at time zero. The tibial attachment site is less critical, offering surgical flexibility.

[Rupture of the anterior cruciate ligament : What must be born in mind in the reconstruction?]

Rupture of the anterior cruciate ligament (ACL) is a common sports injury. Despite continuous improvements over the years, not all patients return to their preoperative activities after treatment of the ACL. Therefore, individualized treatment approaches based on transplant selection, reconstruction technique and biomechanical factors, such as the tibial slope and rotational instability are crucial. Autogenous transplants have different properties in terms of donor site morbidity, healing behavior and risk of rerupture. The individual needs of the patient should therefore be taken into consideration. In terms of the surgical technique, correct tunnel placement based on anatomical landmarks is essential. In addition, concomitant instabilities and meniscus injuries must be addressed. In the event of a rerupture, an exact analysis of the causes is necessary. Ultimately, the success of the treatment depends to a large extent on precise diagnostics and the treatment of both the ACL rupture and any injured accompanying structures.

Current trends in the medial side of the knee: not only medial collateral ligament (MCL)

The medial collateral ligament (MCL) is by far the most commonly injured ligament of the knee. The medial ligament complex covers a broad bony surface on the extraarticular portion of the femur and is highly vascularized, which allows for a high healing potential. For this reason, most MCL complex lesions were treated conservatively in the past. However, recent advancements regarding the MCL anatomy and kinematics highlighted the complex biomechanical behavior of the isolated and combined MCL lesion, and it is now fully appreciated that some MCL lesions warrant surgical treatment. The present review aims to provide the reader with an overview of the new evidence and advancement on the complex anatomy, biomechanics, and treatment of the MCL.

A Flat Reconstruction of the Medial Collateral Ligament and Anteromedial Structures Restores Native Knee Kinematics: A Biomechanical Robotic Investigation

BACKGROUND

Injuries of the superficial medial collateral ligament (sMCL) and anteromedial structures of the knee result in excess valgus rotation and external tibial rotation (ER) as well as tibial translation.

PURPOSE

To evaluate a flat reconstruction of the sMCL and anteromedial structures in restoring knee kinematics in the combined MCL- and anteromedial-deficient knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight cadaveric knee specimens were tested in a 6 degrees of freedom robotic test setup. Force-controlled clinical laxity tests were performed with 200 N of axial compression in 0°, 30°, 60°, and 90° of flexion: 8 N·m valgus torque, 5 N·m ER torque, 89 N anterior tibial translation (ATT) force, and an anteromedial drawer test consisting of 89 N ATT force under 5 N·m ER torque. After determining the native knee kinematics, we transected the sMCL, followed by the deep medial collateral ligament (dMCL). Subsequently, a flat reconstruction of the sMCL with anteromedial limb, mimicking the function of the anteromedial corner, was performed. Mixed linear models were used for statistical analysis (P < .05).

RESULTS

Cutting of the sMCL led to statistically significant increases in laxity regarding valgus rotation, ER, and anteromedial translation in all tested flexion angles (P < .05). ATT was significantly increased in all flexion angles but not at 60° after cutting of the sMCL. A combined instability of the sMCL and dMCL led to further increased knee laxity in all tested kinematics and flexion angles (P < .05). After reconstruction, the knee kinematics were not significantly different from those of the native state.

CONCLUSION

Insufficiency of the sMCL and dMCL led to excess valgus rotation, ER, ATT, and anteromedial tibial translation. A combined flat reconstruction of the sMCL and the anteromedial aspect restored this excess laxity to values not significantly different from those of the native knee.

CLINICAL RELEVANCE

The presented reconstruction might lead to favorable results for patients with MCL and anteromedial injuries with an anteromedial rotatory knee instability.

MCL Repair, Isolated Suture-Tape-Bracing and No Repair for Grade III MCL Tears During ACL Reconstruction Have Similar Outcome for Combined ACL With MCL Injury: A 3-Arm Randomized Controlled Trial

PURPOSE

To compare various medial collateral ligament (MCL) management strategies (repair vs isolated suture-tape bracing vs no repair) combined with anterior cruciate ligament (ACL) reconstruction and analyze the results of MCL subtypes (femoral-sided, mid-substance, and tibial-sided tears) that occur at distinct levels.

METHODS

This study was a double-blind, prospective 3-arm randomized controlled trial. Ninety-six consecutive patients with combined ACL and grade III MCL acute & subacute injuries between 2020 and 2022 with minimum 24-month follow-up were included in the study. Chronic MCL injuries and other ligament injuries were excluded, and computer-generated randomization was performed for allotment into 3 MCL management groups. ACL reconstruction with hamstring autograft was performed and the MCL underwent repair in group 1 (n = 33), isolated suture-tape-bracing in group 2 (n = 32), and no repair in group 3 (n = 31). At follow-up, stress radiographs were used to analyze anterior and medial laxity. The International Knee Documentation Committee score, Lysholm score, Knee Injury and Osteoarthritis Outcome Score, duration of surgery, and cost of surgery were compared. In addition, subgroup analysis was performed to assess outcomes based on location of MCL injury.

RESULTS

Demographic data, duration of injury, mode of injury, and distinct level of MCL injury were similar across groups. Overall, the incidence rates of MCL tears on the femoral side, at the midsubstance, and on the tibial side were 58.3%, 18.7%, and 23.0%, respectively. Postoperatively, significant improvements in range of motion (ROM) and functional scores were observed in all 3 groups (P ≤ .05); however, there were no statistically significant differences among the 3 groups at final follow-up in anterior tibial translation (P = .94), medial opening at 0° of flexion (P = .8) and 30° of flexion (P = .64), ROM (P = .39), International Knee Documentation Committee score (P = .17), Lysholm score (P = .14), and Knee Injury and Osteoarthritis Outcome Score (P = .68). Three patients in group 2 had stiffness at 3 months: 2 were treated with continuous passive motion and physiotherapy, and 1 needed arthrolysis. Medial opening (at 0° and at 30°) was greater in group 3 patients with mid-substance MCL tears (P = .042 and P = .043, respectively). On minimal clinically important difference analysis, more than 80% of patients had improvement in ROM and functional scores, as well as medial opening of less than 5 mm, suggestive of successful outcomes in all 3 groups. The duration of surgery was longer in the repair group (P = .001), whereas cost was higher in the suture-tape bracing group (P = .003).

CONCLUSIONS

MCL treatment with repair, isolated suture-tape-bracing, and no repair results in good radiologic outcomes (medial stress laxity) and functional outcomes when combined with ACL reconstruction. MCL repair or isolated suture-tape-bracing more effectively restores medial-sided stability. Mid-substance MCL tears may need an additional procedure (repair or bracing) to restore medial stability.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

An anteromedial stabilization procedure has the most protective effect on the anterior cruciate ligament in tibial external rotation. A human knee model study

INTRODUCTION

Anterior cruciate ligament (ACL) reconstruction remains associated with the risk of re-rupture and persisting rotational instability. Additional extraarticular anterolateral stabilization procedures stabilize the tibial internal rotation and lead to lower ACL failure rate and improved knee stability. However, data for additional stabilization of tibial external rotation is lacking and the importance of an anteromedial stabilization procedure is less well evaluated. Aim of this study is to investigate the influence of an extraarticular anteromedial stabilization procedure for the stabilization of the tibial external rotation and protection of the ACL from these rotational forces.

METHODS

Internal and external rotations of the tibia were applied to a finite element (FE) model with anatomical ACL, posterior cruciate ligament (PCL), lateral collateral ligament (LCL), medial collateral ligament (MCL) and intact medial and lateral meniscus. Five additional anatomic structures (Anteromedial stabilization/anteromedial ligament, AML, augmented superficial medial collateral ligament, sMCL, posterior oblique ligament, POL, anterolateral ligament, ALL, and popliteal tendon, PLT) were added to the FE model separately and then combined. The force histories within all structures were measured and determined for each case.

RESULTS

The anteromedial stabilization or imaginary AML was the main secondary stabilizer of tibial external rotation (90% of overall ACL force reduction). The AML reduced the load on the ACL by 9% in tibial external rotation which could not be achieved by an augmented sMCL (-1%). The AML had no influence in tibial internal rotation (-1%). In the combined measurements with all additional structures (AML, ALL, PLT, POL) the load on the ACL was reduced by 10% in tibial external rotation.

CONCLUSION

This study showed that an additional anteromedial stabilization procedure secures the tibial external rotation and has the most protective effect on the ACL during these external rotational forces.

Single-Strand "Short Isometric Construct" Medial Collateral Ligament Reconstruction Restores Valgus and Rotational Stability While Isolated Deep MCL and Superficial MCL Reconstruction Do Not

BACKGROUND

Historical MCL (medial collateral ligament) reconstruction (MCLR) techniques have focused on the superficial MCL (sMCL) to restore valgus stability while frequently ignoring the importance of the deep MCL (dMCL) in controlling tibial external rotation. The recent recognition of the medial ligament complex importance has multiple studies revisiting medial anatomy and questioning contemporary MCLR techniques.

PURPOSE

To assess whether (1) an isolated sMCL reconstruction (sMCLR), (2) an isolated dMCL reconstruction (dMCLR), or (3) a novel single-strand short isometric construct (SIC) would restore translational and rotational stability to a knee with a dMCL and sMCL injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Biomechanical testing was performed on 14 fresh-frozen cadaveric knee specimens using a custom multiaxial knee activity simulator. The specimens were divided into 2 groups. The first group was tested in 4 states: intact, after sectioning the sMCL and dMCL, isolated sMCLR, and isolated dMCLR. The second group was tested in 3 states: intact, after sectioning the sMCL and dMCL, and after single-strand SIC reconstruction (SICR). In each state, 4 loading conditions were applied at 0°, 20°, 40°, 60°, and 90° of knee flexion: 8-N·m valgus torque, 5-N·m external rotation torque, 90-N anterior drawer, and combined 90-N anterior drawer plus 5-N·m tibial external rotation torque. Anterior translation, valgus rotation, and external rotation of the knee were measured for each state and loading condition using an optical motion capture system.

RESULTS

sMCL and dMCL transection resulted in increased laxity for all loading conditions at all flexion angles. Isolated dMCLR restored external rotation stability to intact levels throughout all degrees of flexion, yet valgus stability was restored only at 0° of flexion. Isolated sMCLR restored valgus and external rotation stability at 0°, 20°, and 40° of flexion but not at 60° or 90° of flexion. Single-strand SICR restored valgus and external rotation stability at all flexion angles. In the combined anterior drawer plus external rotation test, isolated dMCL and single-strand SICR restored stability to the intact level at all flexion angles, while the isolated sMCL restored stability at 20° and 40° of flexion but not at 60° or 90° of flexion.

CONCLUSION

In the cadaveric model, single-strand SICR restored valgus and rotational stability throughout the range of motion. dMCLR restored rotational stability to the knee throughout the range of motion but did not restore valgus stability. Isolated sMCLR restored external rotation and valgus stability in early flexion.

CLINICAL RELEVANCE

In patients with anteromedial rotatory instability in the knee, neither an sMCLR nor a dMCLR is sufficient to restore stability.

Editorial Commentary: Don't Neglect the Medial Side of the Knee in Patients With Anterior Cruciate Ligament Injury

The medial collateral ligament (MCL) of the knee, as well as the posteromedial complex (including the posterior oblique ligament [POL] and ramp lesions of the meniscus) is often considered the "neglected" ligament or corner because of the belief that these anatomic structures have enormous regenerative potential and therefore hardly ever need surgical treatment. In patients with anterior ligament cruciate (ACL) tears, the overall combined prevalence of MCL (superficial [sMCL] and deep [dMCL]) and isolated dMCL injuries is high (16.5% + 24.8% = 41.3%). In terms of the POL, with a restraint to both internal tibial rotation and valgus rotation during extension, I have some doubts regarding its role in anteromedial instability (AMRI). In fact, AMRI of the knee is caused mainly by injury to both the ACL and the MCLs, resulting in coupled anterior tibial translation and external rotation, causing the medial tibial plateau to subluxate anteriorly. The sMCL provides the most substantial restraint, and the dMCL and POL play more minor roles. Finally, in ACL-deficient knees, ramp lesions are prevalent (9.3%-24.0%), and failing to identify and treat these lesions results in knee instability. In my experience, all unstable ramp lesions should be repaired. In ACL-deficient knees in patients with a tibial slope >5°, an occult ramp lesion should be strongly suspected. In summary, the medial compartment of the knee is complex and encompasses many structures (MCL, POL, ramp, tibial slope), and I believe that we will increasingly move toward individualized treatment.

[Injuries of the medial side of the knee : When and how should they be treated?]

Different medial structures are responsible for restraining valgus rotation, external rotation, and anteromedial rotation. When injured this can result in various degrees of isolated and combined instabilities. In contrast to earlier speculation, the posterior oblique ligament (POL) is no longer considered to be the main stabilizer of anteromedial rotatory instability (AMRI). Acute proximal medial ruptures are typically managed conservatively with very good clinical results. Conversely, acute distal ruptures usually require a surgical intervention. Chronic instabilities mostly occur in combination with instabilities of the anterior cruciate ligament (ACL). The clinical examination is a particularly important component in these cases to determine the indications for surgery for an additional medial reconstruction. In cases of severe medial and anteromedial instabilities, surgical treatment should be considered. Biomechanically, a combined medial and anteromedial reconstruction appears to be superior to other reconstruction methods; however, there is currently a lack of clinical studies to confirm this biomechanical advantage.

Anatomic Flat Double-Bundle Medial Collateral Ligament Reconstruction

Several surgical techniques have been described to restore the anatomy of the medial collateral ligament, involving suture repair and reconstruction, with the latter having been associated with superior postoperative outcomes. Recently, a growing interest in anatomic isometric medial collateral ligament reconstruction (MCLR) has been developed, involving careful evaluation and finding the most appropriate location for the femoral placement of the allograft. Therefore, the purpose of this article is to describe anatomic MCLR aiming to restore medial knee stability by focusing on isometric positions within the native anatomy of the MCL.

Reduction of Collision Risk in Multi-ligament Knee Injury KD-III-M and KD-IV Surgery-Superficial Medial Collateral Ligament Reconstruction with Suture Anchors

Surgical reconstruction of the medial collateral ligament (MCL) can be challenging during multi-ligament knee injury surgery due to the limited working space. There is risk of collision between the guide pin, pulling sutures, reamer, tunnel, implant, and graft of the different ligament reconstructions. In this Technical Note, we detail our senior author's technique for superficial MCL reconstruction using suture anchors and cruciate ligament reconstruction with all-inside techniques. The technique mitigates the risk of collision by confining the reconstruction process and implants for MCL fixation on the medial femoral condyle and medial proximal tibia.

Instabilität des Kniegelenks – medial oder anteromedial?

Hintergrund

Verletzungen des medialen Bandkomplexes gehören zu den häufigsten Knieverletzungen. Sie heilen zwar meist mit konservativer Therapie problemlos aus, persistierende Instabilitäten erhöhen aber die Belastung der Kreuzbänder und benötigen speziell bei deren Beteiligung eine adäquate Therapie.

Anatomie und Biomechanik

Der mediale Seitenbandkomplex besteht im Wesentlichen aus dem oberflächlichen Seitenband (sMCL), welches der primäre Stabilisator gegen Valgus ist, dem tiefen Seitenband (dMCL) mit dessen schräg verlaufendem ventralem Anteil (AML), die nur sekundäre Stabilisatoren gegen Valgus darstellen, aber primär gegen Außenrotation stabilisieren, und dem hinteren Schrägband (POL), das in vollständiger Streckung gegen Valgus sowie gegen Innenrotation stabilisiert.

Therapie

Chronische Instabilitäten bzw. höhergradige Verletzungen mit Dislokation der Bandstümpfe oder multiligamentäre Verletzungen bedürfen einer operativen Versorgung. Im Akutstadium zeigen Avulsionsverletzungen bei anatomischer Refixation gutes Heilungspotenzial, während bei intraligamentären Verletzungen zusätzlich zur Naht der Bandanteile eine Augmentation mit Sehnenmaterial empfohlen wird. Bei chronischen Instabilitäten ist die Differenzierung des Instabilitätsmusters ausschlaggebend für die Wahl der Rekonstruktionstechnik (reine sMCL-Rekonstruktion oder kombinierte Rekonstruktion von sMCL und AML). In beiden Fällen kommt die hier beschriebene Technik mit flachem Transplantat der Anatomie näher als bei konventionellen Verfahren.

Diskussion

Rekonstruktionstechniken unter Verwendung flacher Sehnentransplantate, die alle betroffenen Bandanteile adressieren, haben sich biomechanisch als sehr effektiv erwiesen, komplexe mediale Instabilitäten suffizient zu behandeln. Ob diese auch klinisch überlegen sind, werden zukünftige klinische Studien zeigen müssen.