Association of knee range of motion and continuous passive motion following total knee arthroplasty: a meta-analysis

Abstract

Background: Total knee arthroplasty (TKA) is considered a clinically effective intervention for knee arthritis. Continuous passive motion (CPM), one kind of rehabilitations following TKA, is usually identified to increase knee range of motion (ROM) and promote postoperative recovery of patients. Although many clinical trials have conducted, the results were controversial. Thus it is necessary to determine the effectiveness of CPM on ROM following TKA. Methods: Randomized controlled trials (RCTs) describing CPM and ROM were obtained from the databases PubMed, Cochrane library and Excerpt Medical Database (EMBASE) up to May 2014. All analyses were conducted by Stata 12.0 software. Effect size was measured as standardized mean differences (SMD) with 95% confidence intervals (CIs). A random-effect model was selected to calculate the pooled SMD. Heterogeneity was assessed using the I2 statistic with significance set at a P value less than 0.10. Sub-group analyses were performed based on CPM and standard physiotherapy. Publication bias was analyzed by Egger’s test. Results: Totally, nine RCTs were retrieved in this study. Meta-analysis showed that there were no significant differences between CPM and non-CPM treated patients in terms of active knee flexion ROM and active knee extension ROM at time of discharge from hospital, 6 weeks, 3 months, and more than 6 months respectively. Subgroup analyses showed no differences between CPM group and standard physiotherapy group. Conclusions: CPM following TKA does not have clinical effects on postoperative recovery in aspect of active knee flexion ROM and active knee extension ROM at different treated times.