Comparison of the Position-Matching and Position-Reproducing Tasks to Detect Deficits in Knee Position Sense After Reconstruction of the Anterior Cruciate Ligament

Context: Deficits in knee position sense following reconstruction of the anterior cruciate ligament (ACL) can delay an athlete's return to sport participation and increase the risk of reinjury. Deficits in position sense postreconstruction have been evaluated using either a position-reproducing or position-matching task. Objective: The aim of our study was to combine both to determine which assessment would be more effective to identify deficits in knee position sense. Design: Longitudinal laboratory-based study. Participants: Eleven athletes (6 men and 5 women; mean age, 20.5 [1.2] y), who had undergone ACL reconstruction with an ipsilateral hamstring autograft, and 12 age-matched controls. Interventions: Position sense was evaluated at 6 and 12 months postreconstruction and once for the control group. In addition, peak isokinetic knee extension and flexion strength, at 60°/s and 180°/s, was assessed for the ACL reconstruction group to evaluate possible influences of muscle strength on knee joint position sense. Main Outcome Measures: The variables include the angular differences between the reference limb and indicator limb, and peak torque values of isokinetic knee extension and flexion. Results: Significant matching differences were identified at 6 months postsurgery on the position-matching task, but not at 12 months postsurgery. No significant betweengroup and within-subject differences were identified on the position-reproducing task. No significant matching errors were identified for the control group. There was no correlation between errors in position sense and maximum isokinetic strength. Conclusion: The position-matching task is more sensitive than the position-reproducing task to identify deficits in knee position sense over the first year following ACL reconstruction surgery.