Return of Quadriceps Strength After Primary Total Knee Arthroplasty With Single-Radius Knee System: Five-Year Follow-up.

Preoperative quadriceps muscle strength (isometric peak torque) was expectedly lower on the total knee arthroplasty side in comparison with the unaffected contralateral side and it was further reduced after surgery. This reduction continued for up to 6 months postoperatively. After 6 months, muscle strengths exceeded preoperative values and continued to increase for the following 2 years. From 2 to 5 years postoperatively, there was a tendency for decline; however, the quadriceps muscle strength still exceeded preoperative values. On the nonoperative side, the increase in muscle strength was detected 1 year after surgery and it was still noticeable at 5 years. Contralateral side improvement can be explained by the increased mobility of the patients. Knee Society Scores and function scores were significantly increased at 3 months after surgery and were significantly greater than preoperative values 5 years after surgery. SF-12 (physical score) exceeded preoperative values at 3 months and this increase was observed continuously over the 5-year follow-up. (Journal of Surgical Orthopaedic Advances 26(4):211-215, 2017).