Force Measurements on the Posterior Oblique Ligament and Superficial Medial Collateral Ligament Proximal and Distal Divisions to Applied Loads

Background: There is limited information regarding load responses of the posterior oblique and superficial medial collateral lig-aments to applied loads. Hypotheses: The degree of knee flexion affects loads experienced by the posterior oblique ligament and both divisions of the superficial medial collateral ligament. The posterior oblique ligament provides significant resistance to valgus and internal rota-tion forces near knee extension. Different load responses are experienced by proximal and distal divisions of the superficial medial collateral ligament. Study Design: Descriptive laboratory study. Methods: Twenty-four nonpaired, fresh-frozen cadaveric knees were tested. Buckle transducers were applied to the proximal and distal divisions of the superficial medial collateral and posterior oblique ligaments. Applied loads at 0°, 20°, 30°, 60°, and 90 ° of knee flexion consisted of 10 N.m valgus loads, 5 N.m internal and external rotation torques, and 88 N anterior and pos-terior drawer loads. Results: External rotation torques produced a significantly higher load response on the distal superficial medial collateral liga-ment than did internal rotation torques at all flexion angles with the largest difference at 90 ° (96.6 vs 22.5 N). For an applied val-gus load at 60 ° of knee flexion, loads on the superficial medial collateral ligament were significantly higher in the distal division (103.5 N) than the proximal division (71.9 N). The valgus load response of the posterior oblique ligament at 0 ° of flexion (19.1 N