Functional Anatomy and Classification of Medial Colateral Ligament Injuries: Outline

ANATOMY: The medial collateral ligament (MCL) is one of four major ligaments that supports the knee and is the primary static stabilizer against valgus rotation of the joint. It consists of two components, the superficial (sMCL) and deep MCL (dMCL). The sMCL has one femoral and two tibial attachments. The femoral attachment is situated on the medial epicondyle. The proximal attachment blends into the semimembranosus tendon and the insertion of the distal attachment is at the posteromedial crest of the tibia. The anatomy of the medial side of the knee has been further defined quantitatively with exact attachment locations and relative distances between structures. LaPrade and colleagues reported that the sMCL has one femoral attachment, 3.2 mm proximal and 4.8 mm posterior to the medial epicondyle, and two tibial attachments, a proximal attachment connecting to soft tissue and a distal attachment blending in with the pes anserinus bursa 61.2 mm distal to the knee joint. The dMCL is divided into two: the meniscofemoral and meniscotibial ligaments. The origin of the meniscofemoral comes from the femur just distal to the superficial medial collateral, inserting into the medial menisci. The meniscotibial ligament is thicker and shorter with an attachment forming on the distal edge of the articular cartilage of the medial tibial plateau, coming from the medial meniscus.