The objective of this study was to evaluate the effectiveness of continuous passive motion following total knee arthroplasty in people with arthritis. The primary outcomes were active knee flexion range of motion, passive knee flexion range of motion, active knee extension range of motion, passive knee extension range of motion, length of hospital stay, function and incidence of manipulation under anaesthesia. The secondary outcomes were pain, swelling and quadriceps strength. Effects were estimated as weighted mean differences or standardised mean differences with 95% confidence intervals (CI). Meta-analyses were performed using random-effects models for continuous variables. Twenty randomised controlled trials of 1335 participants met the inclusion criteria. There is high-quality evidence that continuous passive motion increases passive knee flexion range of motion and active knee flexion range of motion. These effects are too small to be clinically worthwhile. There is low-quality evidence that continuous passive motion has no effect on length of hospital stay but reduces the need for manipulation under anaesthesia.
The effects of continuous passive motion on knee range of motion are too small to justify its use. There is weak evidence that continuous passive motion reduces the subsequent need for manipulation under anaesthesia.