The aim of this study was to translate, adapt and validate in French the Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI), a 12-item English language scale assessing the psychological impact of returning to sports after ACL reconstruction.The ACL-RSI scale was forward and back translated, cross-culturally adapted and validated using international guidelines. The study population included all patients who were active in sports and underwent primary arthroscopic ACL reconstruction. The control group included subjects with no history of knee trauma. At the 6-month follow-up, the study population completed the ACL-RSI scale twice within 3-4 days, Knee injury and Osteoarthritis Outcome Score (KOOS) and subjective International Knee Documentation Committee (IKDC) scores. Statistical tests assessed the construct validity, discriminant validity, internal consistency, reliability and feasibility of the ACL-RSI scale.Ninety-one patients with ACL tears and 98 control subjects were included: mean age 31.7 ± 8.1 and 21.8 ± 2, respectively. The ACL-RSI scores were correlated with all KOOS sub-categories (r = 0.22-0.64, p < 0.05) as well as the subjective IKDC score (r = 0.42, p < 0.00001). The mean scores of the study and control groups were significantly different (62.8 ± 19.4 vs. 89.6 ± 11.5, p < 0.00001), and scores were significantly better in patients who returned to the same sport (72.1 ± 21.4 vs. 60.3 ± 18.1, p = 0.008). Internal consistency was high (α = 0.96). Test-retest reproducibility was excellent: ρ = 0.90 (0.86-0.94), p < 0.00001. Administration time was 1.32 ± 0.7 mn, and all items were answered.This study showed that the cross-cultural adaptation of the English version of the ACL-RSI was successful and validated in a French-speaking population. The discriminant capacity of the scale between patients who underwent reconstruction and healthy subjects was confirmed.II.