In a comprehensive study conducted at a medical center in Taiwan from January to December 2006, Chen, et. al., sought to investigate the impact of aggressive continuous passive motion on postoperative outcomes for patients who had undergone total knee arthroplasty (TKA) within six months. TKA, commonly known as knee replacement surgery, is performed to alleviate pain and improve joint mobility in individuals suffering from osteoarthritis.

Total knee arthroplasty is an established surgical procedure for the management of osteoarthritic knee joints, offering relief from pain and enhancing the range of motion. One technique employed postoperatively to promote movement is continuous passive motion (CPM). However, there has been ongoing debate surrounding whether an aggressive CPM approach can significantly improve range of motion and overall quality of life while potentially exacerbating postoperative pain.

This prospective controlled study aimed to shed light on the effects of aggressive continuous passive motion. One hundred and seven patients were recruited for the study, and they were divided into two groups. The control group followed standard rehabilitation protocols, while the experimental group adhered to the same protocols in addition to daily use of CPM for over six hours. The researchers tracked the range of motion, assessed pain levels using the visual analogue scale, and measured patients’ quality of life using the modified Short Form-36 (SF-36) questionnaire.

The study revealed that, among both groups, the range of motion showed improvement. In the treatment group, the range of motion increased from 109° before the surgery to 125° at six months postoperatively. Similarly, the control group exhibited an increase from 111° to 125° over the same period. Pain levels, as measured by the visual analogue scale, diminished significantly in both groups. The treatment group saw a decrease from 7.78 preoperatively to 0.37 at six months postoperatively, while the control group experienced a decrease from 7.92 to 0.21. In terms of quality of life, assessed through the SF-36 questionnaire, both groups showed improvement. The treatment group’s SF-36 score improved from 3.76 preoperatively to 1.77 at six months postoperatively, and the control group exhibited an improvement from 3.68 to 1.83. Importantly, no significant differences were found in range of motion, pain levels, or quality of life between the two groups at each evaluation point.

This study’s findings suggest that, with advancements in total knee arthroplasty surgical techniques, aggressive continuous passive motion does not yield discernible benefits in terms of range of motion, postoperative pain, or quality of life. This research underscores the need for careful consideration of the utility of aggressive CPM in the postoperative management of TKA patients, particularly in light of the potential for increased patient discomfort without commensurate improvements in clinical outcomes.

Reference: Chen, L. H., Chen, C. H., Lin, S. Y., Chien, S. H., Su, J. Y., Huang, C. Y., & Huang, H. T. (2013). Aggressive continuous passive motion exercise does not improve knee range of motion after total knee arthroplasty. Journal of clinical nursing, 22(3-4), 389-394.