Bilateral changes in knee joint laxity during the first year after non-surgically treated anterior cruciate ligament injury

Abstract

ObjectivesAnalyse changes in knee laxity between 3, 6, 12 and 24 months after non-surgically treated ACL injury and to analyse associations between knee laxity and knee function, self-reported knee stability, ACL-Return to Sport after Injury (ACL-RSI), fear and confidence at different timepoints during recovery. DesignProspective cohort study. Participants125 patients (67 males, mean age 25.0 ± 7.0 years) with acute ACL injury. Main outcomeLaxity was measured using KT-1000 arthrometer. Self-reported knee function was assessed using the International Knee Documentation Committee Subjective Knee Form (IKDC-SKF). Confidence and fear were assessed with questions from the ACL-RSI scale. Subjectively knee stability was assessed using SANE. ResultsKnee laxity increased bilaterally from 3 to 12 months, and in the non-involved knee from 3 to 24 months (p˂0.05), although mean change was below 1 mm. Side-to-side difference in knee laxity was correlated with IKDC-SKF (r = −0.283) and knee stability in rehabilitation/sport activities (r = −0.315) at 6 months, but not with confidence/fear. ConclusionKnee laxity increased bilaterally during the first year after non-surgically treated ACL injury, though, the mean change in knee laxity was below 1 mm and the clinical significance is unknown. Knee laxity was weakly associated with knee function and perceived knee stability. Level of evidenceLevel II Trial registrationNCT02931084