Decreased kinesiophobia with virtual embodiment for post-surgical knee rehabilitation: a randomized controlled trial

Anterior cruciate ligament (ACL) ruptures are prevalent, particularly among young athletes. Although ligament reconstruction is the gold standard treatment, the rehabilitation process is extensive and has high reinjury rates. Recovery is often hindered by muscle inhibition and psychological factors like kinesiophobia and associated fear of reinjury. Emerging evidence suggests that motor imagery and action observation could enhance rehabilitation outcomes. Immersive virtual reality (VR) offers a novel way to integrate these techniques, potentially accelerating recovery. In this parallel randomized controlled trial, patients undergoing ACL reconstruction were randomly assigned to receive either conventional rehabilitation alone or conventional rehabilitation plus VR training. Our VR content incorporated several novel elements, including embodiment in a virtual body, first-person perspective, and the performance of virtual exercises guided by a virtual physiotherapist. Another innovative feature was that patients conducted the daily VR training independently at home using a standalone head-mounted display. The VR group performed a 20-min daily VR rehabilitation program for 4 weeks post-surgery, visualizing, planning, and executing movements using an embodied virtual avatar. Self-reported disability (International Knee Documentation Committee score, IKDC), quadriceps strength limb symmetry, active knee extension range of motion (ROM) limb symmetry, and kinesiophobia (Tampa Scale of Kinesiophobia-short form, TSK-11) were measured at baseline, 4, 12, and 36 weeks. Forty-seven participants were randomized, with 44 completing treatment. IKDC scores were not statistically significantly different between groups, despite moderate effect sizes at 4 and 36 weeks (Cohen's d = 0.559, and d = 0.722, respectively). The VR intervention group showed significantly lower kinesiophobia at 4 weeks post-surgery compared to controls (27.00 ± 6.58 vs. 33.35 ± 5.07, Cohen's d = - 0.971, p = 0.045). Both groups demonstrated significant improvements in all outcomes over time (p < 0.001). No significant differences were found for range of motion or quadriceps strength limb symmetry. No adverse events were reported related to the intervention. Reducing kinesiophobia is crucial for timely and effective rehabilitation and return to sport, and for reducing reinjury risk. To our knowledge, this is the first clinical study to investigate the independent use of therapeutic VR at home during post-orthopedic surgery rehabilitation. Future research should explore different VR interventions, including more active exercises and personalized programs, to enhance adherence and optimize recovery. The study was pre-registered with the National Library of Medicine (NCT05080894; first registered 09/20/2021).