Continuous passive motion as an adjunct to active exercises in early rehabilitation following total knee arthroplasty – a randomized controlled trial

Purpose. Continuous passive motion is frequently used post-operatively to increase knee range of motion after total knee arthroplasty in spite of little conclusive evidence. The aim of this study was to examine whether continuous passive motion (CPM) as an adjunct to active exercises had any short time effects (after one week and three months) on pain, range of motion, timed walking and stair climbing. Method. A randomized controlled trial was conducted. A total of 63 patients undergoing primary TKA were randomly assigned into an experimental group receiving CPM and active exercises and a control group receiving active exercises only. Outcomes were assessed by goniometer, visual analogue scale (VAS), timed ‘Up and Go’ test (TUG), timed 40 m walking distance and timed stair climbing. Results. There were no statistical differences between the treatment groups for any outcome measures either at one week or after three months. For the whole group, a significant and 50% reduction in pain score was found after three months (p < 0.01). Compared with before surgery, a significantly impaired knee flexion range of motion (p < 0.01) and a significantly decreased number of patients able to climb stairs were found after three months (p < 0.01). Conclusion. CPM was not found to have an additional short-time effect compared with active physiotherapy. After three months considerable pain relief was obtained for the whole group, the patients preoperative ROM was not restored and the number of patients able to climb stairs had decreased.