Background: Deciding when patients are ready to return to sport (RTS) after an anterior cruciate ligament (ACL) reconstruction (ACLR) is challenging. The understanding of which factors affect readiness and how they may be related is limited. Therefore, despite widespread use of RTS testing, there is a lack of knowledge about which tests are informative on the ability to resume sports.
Purpose: To examine whether there is an association between knee laxity and psychological readiness to RTS after ACLR and to evaluate the predictive value of these measures on sports resumption.
Study design: Cohort study; Level of evidence, 2.
Methods: Patients aged ≥16 years engaged in physical activity/sports before injury were recruited at routine clinical assessment 9-12 months after ACLR. Exclusion criteria were concomitant ligament surgery at ACLR and/or previous ACL injury in the contralateral knee. At baseline, a project-specific activity questionnaire and the ACL-Return to Sport After Injury (ACL-RSI) scale were completed. Knee laxity was assessed by use of the Lachman test, KT-1000 arthrometer, and pivot-shift test. Two years after surgery, knee reinjuries and RTS status (the project-specific questionnaire) were registered. Associations between psychological readiness and knee laxity were evaluated with the Spearman rho test, and predictive ability of the ACL-RSI and knee laxity tests were examined using regression analyses.
Results: Of 171 patients screened for eligibility, 132 were included in the study. There were small but significant associations between the ACL-RSI score and the Lachman test (rho = -0.18; P = .046) and KT-1000 arthrometer measurement (rho = -0.18; P = .040) but no association between the ACL-RSI and the pivot-shift test at the time of recruitment. Of the total patients, 36% returned to preinjury sport level by 2 years after surgery. Higher age, better psychological readiness, and less anterior tibial displacement (KT-1000 arthrometer measurement) were significant predictors of 2-year RTS (explained variance, 33%).
Conclusion: Small but significant associations were found between measurements of psychological readiness and anterior tibial displacement, indicating that patients with less knee laxity after ACLR feel more ready to RTS. ACL-RSI and KT-1000 arthrometer measurements were independent predictors of 2-year RTS and should be considered in RTS assessments after ACLR.
Keywords: ACL; joint laxity; orthopaedics; psychological aspects of sport; return to sport.