A Cochrane review (abstract , review [Abstract]) included 24 studies with a total of 1 445 subjects. Continuous passive motion (CPM) combined with standard postoperative care was compared with standard postoperative care with or without additional knee exercises to one or both groups. CPM increased passive knee flexion range of motion (ROM) (MD 2 degrees, 95% CI 0 to 5, P = 0.02)The medium- and long-term effects are similar although the quality of evidence is lower.
There was low-quality evidence to indicate that CPM does not have clinically important short-term effects on pain: mean pain was 3 points in the control group, CPM reduced pain by 0.4 points on a 10-point scale (95% CI -0.8 to 0.1) or absolute reduction of -4% (95% CI -8% to 1%).
There was moderate-quality evidence to indicate that CPM does not have clinically important medium-term effects on function: mean function in the control group was 56 points, CPM decreased function by 1.6 points (95% CI -6.1 to 2.0) on a 100-point scale or absolute reduction of -2% (95% CI -5% to 2%). The SMD was -0.1 standard deviations (SD) (95% CI -0.3 to 0.1).
There was moderate-quality evidence to indicate that CPM does not have clinically important medium-term effects on quality of life: mean quality of life was 40 points in the control group, CPM improved quality of life by 1 point on a 100-point scale (95% CI -3 to 4) or absolute improvement of 1% (95% CI -3% to 4%).
There was very low-quality evidence to indicate that CPM reduces the risk of manipulation under anaesthesia; risk of manipulation in the control group was 7.2%, risk of manipulation in the experimental group was 1.6%, CPM decreased the risk of manipulation by 25 fewer manipulations per 1000 (95% CI 9 to 64) or absolute risk reduction of -4% (95% CI -8% to 0%). The risk ratio was 0.3 (95% CI 0.1 to 0.9).
There was low-quality evidence to indicate that CPM reduces the risk of adverse events; risk of adverse events in the control group was 16.3%, risk of adverse events in the experimental group was 15%, CPM decreased the risk of adverse event by 13 fewer adverse events per 1000 or absolute risk reduction of -1% (95% CI -5% to 3%). The risk ratio was 0.9 (95% CI 0.6 to 1.3). The estimates for risk of manipulation and adverse events are very imprecise and the estimate for the risk of adverse events does not distinguish between a clinically important increase and decrease in risk.
There was insufficient evidence to determine the effect of CPM on participants' global assessment of treatment effectiveness.
Primary/Secondary Keywords