Clinical Outcome Measures and Return-to-Sport Timing in Adolescent Athletes After Anterior Cruciate Ligament Reconstruction

Context: Multiple factors are likely associated with an adolescent athlete's ability to return to play after anterior cruciate ligament (ACL) reconstruction (ACLR). Objective: To investigate the relationship between self-reported and functional outcome measures on return-to-play timing in an adolescent population, in athletes who returned and those who did not return to sport, and to identify a cutoff value for isometric quadriceps strength that could serve as a clinical target for maximizing the odds of returning to play after ACLR. Design: Cross-sectional study. Setting: Outpatient clinic. Patients or Other Participants: Adolescent athletes who underwent ACLR and completed clinical measures at their 3-and 6-month follow-up appointments were included. Main Outcome Measure(s): Clinical measures included functional outcomes of isometric and isokinetic strength tests and the Anterior Cruciate Ligament Return to Sport After Injury scale and the pediatric version of the International Knee Documentation Committee subjective form. Physician clearance dates for return to play were obtained from patient records. Results: Higher strength measures were associated with better scores on the Anterior Cruciate Ligament Return to Sport After Injury and the pediatric version of the International Knee Documentation Committee instruments at each follow-up. Differences were found in isometric extension strength (P = .001) and isokinetic extension strength at 180 degrees/s (P= .03) and 300 degrees/s (P= .002) between patients who returned to sports and those who did not. A 6-month isometric extension deficit (mean Limb Symmetry Index = 85.48 +/- 23.15) displayed high accuracy (area under the curve = 0.82, 95% confidence interval = 0.68, 0.95) for identifying patients who returned to play after ACLR. Conclusions: Higher strength measures at both 3 and 6 months after ACLR were associated with greater self-reported knee function and greater readiness to return to functional activities at 6 months and ultimately earlier return to sport in adolescent athletes. These results provide evidence that self-reported outcome scores should be used as an additional screening tool in conjunction with quadriceps strength testing to help provide realistic recovery timeframes for adolescent patients.