Sex-related differences after ACL reconstruction differ between early functional recovery and 5-year outcomes.

PURPOSE: To compare early functional recovery and 5-year clinical, sports and psychological outcomes after anterior cruciate ligament reconstruction (ACLR) according to sex.

METHODS: This retrospective cohort study included consecutive patients who underwent primary ACLR between January 2017 and December 2019, with standardized 6-month functional and psychological assessment and available 5-year follow-up. Patients were analyzed according to sex. Baseline characteristics, 6-month quadriceps strength and hop-test performance, and 5-year patient-reported and sports outcomes were compared between groups. The primary outcome was recovery of preinjury activity level at 5 years, defined as a post-operative Tegner score greater than or equal to the preoperative Tegner score. Multivariable logistic regression was used to identify factors independently associated with the primary outcome.

RESULTS: A total of 479 patients were included, comprising 173 women (36.1%) and 306 men (63.9%). At 6 months, men demonstrated higher quadriceps limb symmetry and lower hop-test deficits than women, whereas anterior cruciate ligament return to sport after injury (ACL-RSI) did not differ significantly between groups. At 5 years, overall return-to-sport rates were similar between sexes (187 [61.2%] men vs. 103 [59.5%] women, p = 0.85), but men had higher post-operative Tegner (6 [5-7] vs. 5 [4-7], p < 0.001), IKDC (82.5 [75.7-87.3] vs. 79.5 [72.8-86.3], p = 0.02) and ACL-RSI scores (77.5 [55.8-92.5] vs. 69.2 [53.3-85.8], p = 0.02) and were more likely to recover their preinjury activity level (137 [45.1%] vs. 48 [28.1%], p < 0.001). In the baseline-adjusted multivariable model, male sex was independently associated with recovery of preinjury activity level (odds ratio [OR] = 2.16, 95% confidence interval [CI] = 1.40-3.39; p < 0.001). This association persisted after inclusion of 6-month recovery variables (OR = 1.93, 95% CI = 1.20-3.15; p = 0.007), while lower single-hop deficit was also independently associated with the outcome.

CONCLUSIONS: Men and women did not demonstrate the same recovery profile after ACLR. Early differences were mainly functional, whereas 5-year differences involved recovery of preinjury activity level, subjective knee function and psychological readiness, despite similar overall return-to-sport rates. These findings suggest that return to sport should not be interpreted as equivalent recovery quality after ACLR.

LEVEL OF EVIDENCE: Level III.