A rehabilitation programme performed in darkness after anterior cruciate ligament reconstruction reduces the risk of secondary injuries

To evaluate whether integrating partial visual deprivation during the reathletization phase after anterior cruciate ligament (ACL) reconstruction improves proprioceptive recovery and reduces the risk of graft failure or contralateral injuries. We conducted a retrospective, single-centre cohort study including patients aged older than 16 years who underwent ACL reconstruction with autograft and concomitant anterolateral ligament reconstruction between November 2017 and March 2020. Patients voluntarily chose between two reathletization programmes starting from the fourth postoperative month: Group 1 (Conventional): exercises performed exclusively in a well-lit environment (n&#x2009;=&#x2009;372). Group 2 (Darkness): exercises alternating between well-lit and controlled dark conditions (<10&#x2009;lux) (n&#x2009;=&#x2009;131). Primary outcome was ACL graft re-rupture; secondary outcomes included contralateral ACL rupture, functional scores (International Knee Documentation Committee [IKDC] Subjective Knee Form, Knee Injury and Osteoarthritis Outcome Score [KOOS], Lysholm, ACL-Return to Sport after Injury [ACL-RSI]) and return-to-sport level (Tegner Activity Scale). A minimum follow-up of 5 years was required. Groups were matched for age, sex, graft type, baseline sports level and associated meniscal lesions. A total of 446 patients (mean follow-up: 5.8&#x2009;&#xb1;&#x2009;0.7 years) were analysed. The overall re-rupture rate was 5.4% and tended to be lower in the Darkness group (3.2%) compared to the Conventional group (7.1%; p&#x2009;=&#x2009;0.18). Contralateral ACL ruptures were significantly less frequent in the Darkness group (5.7% vs. 13.1%; p&#x2009;=&#x2009;0.01). Functional scores (IKDC, KOOS, Lysholm, ACL-RSI) showed no significant differences between groups. However, the final return-to-sport level was significantly higher in the Darkness group (Tegner 6.0 vs. 5.3; p&#x2009;=&#x2009;0.04). A reathletization programme incorporating partial visual deprivation after ACL reconstruction may reduce the risk of contralateral injuries, despite no significant difference in functional scores. This simple, feasible approach warrants further evaluation in prospective controlled studies. Level III.