Current concepts on management of medial and posteromedial knee injuries

Abstract

Traditionally, while managing ligament injuries around the knee, medial side injuries are frequently overlooked or considered 'benign' with very little influence on overall knee stability outcomes. However, much has changed in the recent past, and like the lateral side of the knee, it is gaining considerable attention. It is now well known that the Medial collateral ligament and Posteromedial corner are fundamentally two distinct structures that differ in anatomy and biomechanics. When it comes to decision making between conservative versus operative approach for medial side injuries, treating orthopaedic surgeons are subjected to walking on a thin line trying to balance between potential residual laxity and joint stiffness. This review will delve into some of the recent works focusing on the medial side injuries and discuss the evolving concepts.

Keywords: Knee; Medial collateral ligament; Posteromedial corner; Reconstruction; Repair.

Fig. 1

(A, B,C): (A) Cadaveric image of the medial side of the right knee. White, Green, and deep blue pinheads represent medial epicondyle (ME), adductor tubercle (AT), and gastrocnemius tubercle (GT). The interrupted black hashed line represents the medial joint line, while the bidirectional black arrow shows the superficial medial collateral ligament (sMCL) over the tibia. Light blue and yellow circles represent the femoral attachment of sMCL and posterior oblique ligament (POL). (B) Coronal cadaveric section of the medial side of the knee showing dMCL (deep medial collateral ligament). (C) Cadaveric image of medial side of the knee showing POL and its parts. The superficial arm (SA) is within the blue circle, central arm (CA) between two hashed line, while capsular arm (CpA) within the red circle Abbreviations- P, patella, MPFL, medial patellofemoral ligament; SM, Semimembranosus; MFC, medial femoral condyle; MM, medial meniscus; MTP, medial tibial plateau; Cadaveric Image courtesy- Dr. Charlie Brown, UAE.

Fig. 2

Ecchymoses (yellow arrows) on the medial side of the knee due to injury to medial ligaments of the knee.

Fig. 3

Plain anteroposterior stress radiograph of the knee with the knee in flexion and valgus stress showing increased medial joint gapping (yellow arrow).

Fig. 4

Fat suppressed T2 weighted coronal MRI image showing avulsion of superficial MCL from the tibial side (wave sign, blue arrow), deep MCL tear (orange arrow), and extrusion of lateral meniscus due to radial tear (yellow arrow). The lateral femoral condyle shows bone contusion (due to valgus overload of the lateral compartment.

Fig. 5

Arthroscopic image of right knee medial compartment shows increased medial joint space (black arrow). Yellow star indicates ecchymoses over the meniscotibial component of deep MCL, causing medial meniscal elevation towards the femoral condyle.

Fig. 6

A recommended algorithm for treatment of acute sMCL tear. This algorithm is based on finding that MCL was graded (I,II,III) with valgus stress in 20° flexed knee while it was normal in extension, signifying that sMCL was torn while PMC was fine. ∗ indicates special indications for operative intervention for sMCL tear such as tibial side avulsion, bipolar tears, joint entrapment and bony avulsions. ^$ indicates Taketomi type of sMCL avulsions. sMCL, superficial medial collateral ligament, ACL, anterior cruciate ligament; PCL, Posterior cruciate ligament; AMRI, anteromedial rotary instability; rehab., rehabilitation; ACLR, Anterior cruciate ligament reconstruction; PCLR, Posterior cruciate ligament reconstruction.

Fig. 7

(A to D): Various medial side reconstruction techniques. (A) Double bundle anatomic sMCL reconstruction (white arrows over reconstructed sMCL). (B) Dual incision anatomic Double bundle sMCL reconstruction (green arrows indicate two separate incisions over femur and tibia). (C) Double bundle non-anatomic sMCL-POL reconstruction (blue arrow over sMCL and yellow arrow over POL). (D) Anatomic Double bundle sMCL-POL reconstruction (Black arrow indicates MCL, blue arrow indicates POL). sMCL, superficial medial collateral ligament; POL, posterior oblique ligament. (Cadaveric image courtesy- Dr Charlie Brown, UAE).