Effectiveness of exercise prehabilitation before anterior cruciate ligament reconstruction on functional outcomes – a single-blinded randomized controlled trial

Objective: To compare the effectiveness of an individually tailored, adaptive, guided, structured and criteria-based preoperative rehabilitation program (IG) to a structured, non-guided, self-administered home training program (CG) in individuals after an anterior cruciate ligament (ACL) rupture. Methods: We enrolled participants 16 to 60 years with a unilateral ACL rupture, scheduled for reconstruction using a hamstring or quadriceps tendon autograft. They were assessor-blinded 1:1 block-randomized to the IG or the CG. Self-reported knee function, assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), was the primary outcome. Secondary outcomes included functional measures (range of motion, muscle strength, functional limb asymmetries, and hopping ability) as well as self-reported psychological readiness to return to sport. Parameters were assessed at up to seven time points: anamnesis in the hospital, 1 to 7 days before the surgery, on the day of surgery, 30, 60, 90, and 180 days post-surgery. Intention-to-treat based linear mixed models were calculated using the change scores since anamnesis. Results: Of 114 enrolled participants (mean age = 31.03, SD = 10.30 years; 53% females), 58 participants discontinued intervention or dropped out. The IG (KOOS score anamnesis: 46.04, 95% confidence interval = [45.07 to 47.02]; pre-reconstruction: 58.52, [57.51 to 59.54]) demonstrated a more pronounced preoperative improvement in the KOOS score compared to the CG (51.01, [50.10 to 51.92]; 59.18, [58.40 to 59.96]). The interaction (group*time) of the KOOS sum score differed for the change score to the surgery day (p = 0.039) and to 60 days postoperative (p = 0.039). Conclusion: The individually tailored preoperative rehabilitation program may improve perceived knee function more than self-guided training. Caution and future research are needed as the effects were small. Trial registration: German Register of Clinical Trials, DRKSID: DRKS00030312, Date of registration in DRKS 26.09.2022.