Efficacy of continuous passive motion compared to physiotherapy in rehabilitation after total knee replacement: a prospective randomized controlled non-inferiority trial

Successful total knee replacement (TKR) heavily depends on postoperative rehabilitation. This study aims to investigate the efficacy of continuous passive motion (CPM) partially replacing group physiotherapy in an inpatient rehabilitation setting in order to contribute to the lack of physiotherapists in patients' care. Adult patients after TKR were included. A prospective randomized controlled two-center trial was conducted across inpatient rehabilitation facilities in Germany. Participants were randomly assigned to CPM or group physiotherapy. In addition, all participants received the same standard rehabilitation program. Primary outcome was the Staffelstein Score, and secondary outcome measures included Oxford Knee Score, range of motion (ROM), pain, and return to work. Non-inferiority margin for Staffelstein Score was set at ±5% of maximum scores based on previous collected data. Results indicate no significant differences between CPM and physiotherapy groups in the Staffelstein Score (CPM: 94 ± 10 points; group physiotherapy: 92 ± 10 points; P > 0.05), ROM, or pain management at discharge from rehabilitation facility. This study underscores the potential of CPM as a valuable component of TKR rehabilitation, providing comparable outcomes to traditional physiotherapy. However, individualized physiotherapy remains integral to optimizing long-term success. Future research should explore extended follow-up periods and diverse patient populations to further elucidate CPM's role in TKR rehabilitation.