Continuous Passive Motion After Total Knee Arthroplasty: A Systematic Review and Meta-analysis of Associated Effects on Clinical Outcomes

To evaluate the efficacy of continuous passive motion (CPM) after total knee arthroplasty (TKA) and whether the use of CPM is related to improved clinical and functional outcomes.A systematic MEDLINE search via Web of Science, Cochrane Library, and PubMed databases was conducted.English-language articles published between January 2000 and May 2018 reporting the related clinical outcomes of CPM after TKA were included. A total of 3334 titles and abstracts were preliminarily reviewed, of which 16 studies were included according to the eligibility criteria.Two different reviewers were selected to perform the study extraction, independent of each other. If there were any disagreements regarding the final list of studies, the third reviewer reviewed the list as an arbitrator for completeness.A total of 16 trials with 1224 patients were included. The pooled results revealed that use of CPM did not show a statistically significant improvement of postoperative knee range of motion (ROM) except for middle-term passive knee extension and long-term active knee flexion ROM. Also, CPM therapy did not show a significant positive effect on the functional outcomes. No significant reduction in length of stay (LOS) and incidence of adverse events (AEs) was identified.Among patients undergoing TKA, neither the ROM nor the functional outcomes could be improved by CPM therapy. Moreover, the risk of AEs and LOS could not be reduced by application of CPM. The current available evidence suggested that this intervention was insufficient to be used routinely in clinical practice.