Postoperative Anterior Cruciate Ligament–Return to Sport after Injury Scores Predict Reinjury in Adolescent Athletes

Background: Adolescents experience the highest rates of both ipsilateral and contralateral reinjury following anterior cruciate ligament (ACL) reconstruction (ACLR). Psychological readiness has been shown to be associated with ACL reinjury although the exact relationship is unclear because prior investigations have neither tracked its evolution over time nor stratified results by age and sex. Purpose: To perform an age- and sex-specific, longitudinal analysis of the relationship between Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) score and the risk of ipsilateral/contralateral ACL injury in adolescents. Study Design: Cohort study; Level of evidence, 3. Methods: A consecutive cohort of adolescents (<18 years old) who underwent primary ACLR at a single center completed the ACL-RSI preoperatively and at 3, 6, and 9 months. Functional strength and jump metrics were also collected at 9 months. Return to play (RTP) and the incidence of second ACL injury were recorded at 5 years. Differences in ACL-RSI were evaluated and receiver operating characteristic curves were used to quantify the discriminative ability of the ACL-RSI score. Results: There were 539 adolescents included. The RTP rate was 89.7% at a mean time of 10.8 ± 3.1 months. The rate of second ACL injury was 22.2% (ipsilateral 9.7%; contralateral 12.5%) at 5 years. Adolescents who sustained a contralateral ACL injury had higher ACL-RSI scores at 9 months for male patients (85.1 ± 14.4 vs 76.7 ± 17.6; P = .004) and at 6 months for female patients (79.9 ± 15.2 vs 67.8 ± 20.2; P = .017) than those who remained uninjured. In contrast, male adolescents who suffered graft rupture recorded lower 9-month ACL-RSI scores than uninjured peers (66.2 ± 18.5 vs 76.7 ± 17.6; P = .003). The ACL-RSI was predictive of ipsilateral reinjury in male adolescents but not in females. Conclusion: Serial ACL-RSI scores yield distinct, sex-specific risk profiles in adolescents. Low scores during rehabilitation identify athletes vulnerable to ipsilateral graft failure, whereas rapidly rising, high scores indicate those at risk for contralateral reinjury. This highlights the need to interpret the ACL-RSI score taking age and sex into consideration.