The ligamentous structures of the posterolateral aspect of the knee.

Fifty cadaver knees were dissected in order to examine their ligamentous structures and gain an increased understanding of their morphology and their functional contribution to the posterolateral stability of the knee joint. The fabellofibular ligament was found in 34 knee joints (68%); its homologue, the short lateral ligament, was found in only 2 (4%). The arcuate ligament was identifiable in 12 knees (24%) as a thin, membranous capsular structure; more than half of these ligaments lacked either a medial or a lateral limb. The fibular origin of the popliteus was found in 49 knees (98%) with a mean width of 9.3 mm. This strong, tendinous band completes the span of the popliteal tendon between the lateral femoral condyle and the fibular styloid. Based on its course and its relation to the knee joint, we believe it provides static stabilization to the knee by preventing external rotation and posterior translation of the lateral tibial condyle.