Clinical outcomes and predictive modelling of return to sport after anterior cruciate ligament reconstruction: development and internal validation of the RTS–Lemarié score

Anterior cruciate ligament reconstruction (ACLR) aims to restore knee stability and facilitate safe return to sport (RTS). Graft choice between hamstring tendon (STRI) and bone–patellar tendon–bone–like constructs (HTH) remains controversial, while no validated predictive tool currently exists to estimate individual RTS probability. This study evaluated clinical outcomes of ACLR and developed a predictive score for RTS. We retrospectively analyzed 103 patients undergoing primary ACLR (69.9% HTH, 30.1% STRI) between 2017 and 2023. Demographic data, sport type, meniscal status, and surgical year were collected. Outcomes included RTS at 12 months, graft re-rupture, IKDC and Tegner scores. Multivariable logistic regression identified predictors of RTS, with performance assessed by area under the curve (AUC), calibration, Brier score, and decision curve analysis (DCA). Regression coefficients were converted into a simplified additive model (RTS–Lemarié score). Mean age was 22.3 ± 5.5 years; 77.7% were male and 49.5% participated in pivoting sports. At 12 months, 79.6% of patients achieved RTS at or above pre-injury level. Median time to RTS was 7.8 months (IQR 6.5–9.1). Re-rupture occurred in 5.8% of cases. IKDC improved from 45.0 ± 12.1 to 83.5 ± 9.2 (p < 0.001), while Tegner decreased slightly from 7.0 ± 1.5 to 6.3 ± 1.2 (p < 0.001). HTH grafts showed a trend toward higher RTS and lower re-rupture risk compared with STRI. Independent predictors of RTS included age, sport type, meniscal integrity, graft choice, and surgery after 2021. The final model achieved an AUC of 0.80, good calibration, and net benefit on DCA. Stratification by the RTS–Lemarié score yielded RTS rates of 92.5%, 78.3%, and 61.1% in favorable, intermediate, and unfavorable groups, respectively (p < 0.01). ACLR with both HTH and STRI autografts achieved high RTS rates and low re-rupture incidence in sports-active patients. The RTS–Lemarié score demonstrated strong predictive performance and clinical applicability, supporting its role as a practical tool for individualized counseling and risk stratification. External multicenter validation is warranted. Level III – Retrospective comparative cohort study;