Changes in pain and physical function during waiting time and 3 months after knee joint arthroplasty.

OBJECTIVE To determine changes in physical and social function during a prolonged preoperative waiting period and at 3 months after total knee arthroplasty. SUBJECTS Forty-three patients were evaluated on the day that surgery was decided, the day before surgery, and 3 months afterwards. METHODS Knee pain and function were assessed using a visual analogue scale and a functional assessment system. Isometric knee flexion extension strength and mobility were measured. RESULTS Knee pain and muscle strength remained unchanged during the mean waiting time of 10 (standard deviation 8) months. On the affected side, knee extension strength was 19% weaker than on the contralateral side and did not change pre-operatively. Post-operatively, knee pain decreased by 50%. Knee extension strength decreased by 26% and flexion strength by 12% compared with the initial assessments. Knee extension strength of the operated side was 42% lower than on the non-operated side. Knee flexion mobility was decreased by 8%, while the initially detected knee extension deficit of 10 degrees (SD 7) remained unchanged. The functional assessment system did not detect any changes in function. CONCLUSION Waiting time did not affect knee pain or isometric knee extension/flexion strength. Three months post-operatively, knee pain had decreased significantly, but the strength of the operated knee was significantly lower than the pre-operative level.