THE POPLITEOFIBULAR LIGAMENT - REDISCOVERY OF A KEY ELEMENT IN POSTEROLATERAL STABILITY

We have recently become aware of a strong direct attachment of the pop liteal tendon to the fibula, To investigate the importance of this att achment, we examined 20 cadaveric knees, The popliteofibular ligament was identified in all 20 knees. The cross-sectional area of the poplit eofibular ligament was 6.9 +/- 2.1 mm(2), compared with 7.2 +/- 2.7 mm (2) for the lateral collateral ligament, Biomechanical testing of thes e structures, simulating a purely varus stress on the knee, revealed t hat the lateral collateral ligament always failed first, followed by t he popliteofibular ligament, and then the muscle belly of the popliteu s. The mean maximal force to failure of the popliteofibular ligament a pproached 425 N (range, 204 to 778), compared with 750 N (range, 317 t o 1203) for the lateral collateral ligament. Our results indicate that the popliteofibular ligament contributes to posterolateral stability.