Anatomy of the knee joint lateral retinaculum.

Dissections of the fiber orientation and interconnections of the lateral knee retinacula in 23 cadaver knees and one fresh knee demonstrate a superficial, oblique retinacular ligament running from fascia lata to patella. Deep to this structure are a separate distinct transverse band to the patella, an epicondylopatellar and a patellotibial band. Awareness of these distinct structures should be helpful to the surgeon performing a lateral retinacular release. The lateral knee retinaculum is oriented longitudinally with the knee extended. In view of this, there is little to support the lateral tibial plateau posteriorly once the anterior cruciate ligament has been torn. The fabellofibular ligament gives minimal supportive strength to the posterolateral corner. The lateral knee has two distinct functional layers. The outer layer consists of superficial and deep retinacular fibers, iliotibial band, lateral collateral, biceps tendon, and fabellofibular ligament; these are the main restaining, retinacular structures of the lateral knee. Deep to these structures lie the popliteus tendon, the true joint capsule, and synovium which have little ability to prevent anterolateral rotatory instability once the anterior cruciate ligament has been disrupted. The term "lateral capsular ligament" is anatomically incorrect, and specific retinacular structures should be designated in describing the lateral knee.