At the completion of formal rehabilitation after anterior cruciate ligament reconstruction, functional capacity is only restored in a small proportion of affected individuals. Therefore, the end of formal rehabilitation is not the end of functional rehabilitation.

To compare adherence to and effectiveness of a late-stage rehabilitation programme with usual care after anterior cruciate ligament (ACL) reconstruction.

This prospective, double-blind, multicentre, parallel group, randomised controlled trial, included people aged 18 to 35 years after formal rehabilitation completion (mean [SD] 241 [92] days post-reconstruction). Participants were block-randomised to a 5-month neuromuscular performance intervention (Stop-X group) or usual care (medically prescribed standard physiotherapy, individual formal rehabilitation, home-exercises). All outcomes were measured once/month. Primary outcome was normalised knee separation distance on landing after drop jump. Baseline-adjusted linear mixed models were calculated.

In total, 112 participants (Stop-X: 57; Usual care: 55,) were analysed. Initially, mean (SD) intervention frequency (units/week) was higher in the Stop-X than the Usual care group: 2.65 (0.96) versus 2.48 (1.14) units/week in the first and 2.28 (1.02) versus 2.14 (1.31) units/week in the second month. No between-group*time(*baseline)-differences were found for the primary outcome. Between-group*time-effects favoured the Stop-X-group at 2 months (fewer self-reported knee problems during sport, KOOS-SPORT) (estimate = 64.3, 95% CI 24.4-104.3 for the Stop-X), more confidence to return to sport (ACL-RSI) (62.4, 10.7-114.2), fewer pain-associated knee problems (KOOS-PAIN) (82.8, 36.0-129.6), improved everyday activity abilities (KOOS-ADL) (71.1, 6.4-135.7), and improved limb symmetry index in the front hop for distance at 3 and 4 months (0.34, 0.10-0.57; 0.31, 0.08-0.54). No between-group*time-effects occurred for kinesiophobia, symptom-associated knee problems or balance hops performance. At the end of the intervention, 79% of the Stop-X and 70% of the Usual care participants (p<0.05) had successfully returned to their pre-injury sport type and level.

The Stop-X intervention was slightly superior to usual care as part of late-stage rehabilitation after ACL-reconstruction. The small benefit might justify its use after formal rehabilitation completion.