Effect of ACL Reconstruction and Tibial Rotation on Anterior Knee Laxity

***Note: Figures may be missing for this format of the document ***Note: Footnotes and endnotes indicated with brackets The anterior cruciate ligament (ACL) is the primary restraint to anterior translation of the tibia on the femur. Research suggests that resistance to anterior translation changes as the tibia is rotated internally and externally. This study assessed the degree to which ACL reconstruction and tibial rotation affects anterior knee laxity. Nine subjects with ACL lesions and functional instabilities participated in the study. Subjects were measured 1 to 10 days before surgery and 6 to 8 months after ACL reconstruction using the Kr-1000 knee arthrometer. A mechanical leg stabilizer was used to assess anterior translation at 20 ° of knee flexion in three positions: internal rotation of 15°, neutral, and external rotation of 15°. Subjects were measured at 89 and 67 N of anterior force. Data were analyzed with a three-factor (test x position x force) repeated measures ANOVA. Following surgery, reduction in laxity (mm) for the three positions (internal rotation, neutral, and external rotation) was 1.9, 2.8, and 3.4, respectively, at 89 N and 1.5, 2.0, and 2.6, respectively, at 67 N. The degree o