How iliotibial tract injuries of the knee combine with acute anterior cruciate ligament tears to influence abnormal anterior tibial displacement

Abstract

A knowledge of the patterns of injury to the compo nents of the iliotibial tract allows a clearer interpretation of motion limits testing in patients with abnormal ante rior tibial translation of the knee (anterior cruciate liga ment-deficient knees). Eighty-two consecutive patients with acute knee in juries were classified as anteromedial-anterolateral ro tatory instability (anterior cruciate ligament-deficient) based on the abnormal motion demonstrated by clinical examination tests for instability. At surgery, injuries to the intraarticular and extraarticular anatomic structures were identified and correlated to the abnormal grades of motion demonstrated by the knee motion limits ex amination. Tears of the anterior cruciate ligament occurred in 80 (98%) of the knees. However, the grade of abnormal motion demonstrated by the Lachman and pivot shift tests was quite variable. This variation did not correlate statistically with anterior cruciate ligament tears. Injuries to the anatomic components of the iliotibial tract were confirmed in 76 (93%) of the knees. These injuries correlated highly with variations in grades of abnormal motion detected by the following tests: lateral joint line opening at 30° ( r2 = 0.05); Lachman test ( r2 = 0.08); pivot shift ( r2 = 0.16); and anterior translation at 90° of flexion ( r2 = 0.34). Thus, injuries to the components of the iliotibial tract are thought to contrib ute to the variation in grades of abnormal motion ob served in this complex subgroup of anterior tibial trans lation instabilities.