Aggressive continuous passive motion exercise does not improve knee range of motion after total knee arthroplasty

Aims and objectives. The aim of this study was to evaluate the effects of continuous passive motion on the range of motion, postoperative pain and life quality of patients undergoing total knee arthroplasty within six months after the operation. Background. Total knee arthroplasty reduces pain and improves range of motion of the osteoarthritic knee joint. Continuous passive motion increases postoperative movement, but there is some controversy regarding whether aggressive continuous passive motion can improve range of motion or life quality, and whether it induces more pain. Design. A prospective controlled study was conducted in a medical centre in Taiwan from January to December 2006. Methods. One hundred and seven patients were recruited. The patients underwent the basic rehabilitation protocols (the control group) or the basic rehabilitation protocols and additional daily use of continuous passive motion for more than six hours per day (the experimental group). The range of motion, modified Short Form‐36 (SF‐36) and semi‐quantitative visual analogue scale were recorded. Results. Range of motion increased from 109° preoperatively to 125° at six months postoperatively in the treatment group and from 111° preoperatively to 125° at six months postoperatively in the control group. Visual analogue scale decreased from 7·78 preoperatively to 0·37 at six months postoperatively in the treatment group and from 7·92 preoperatively to 0·21 at six months postoperatively in the control group. The SF‐36 improved from 3·76 preoperatively to 1·77 at six months postoperatively in the treatment group and from 3·68 preoperatively to 1·83 at six months postoperatively in the control group. There was no significant difference in range of motion, visual analogue scale and SF‐36 between groups at each visit. Conclusion. With the advances in total knee arthroplasty surgical technique, aggressive continuous passive motion does not provide obvious benefits. Relevance to clinical practice. Total knee arthroplasty can alleviate pain and improve range of motion, but aggressive continuous passive motion does not provide additional benefits.