Quadriceps muscle function in primary total knee arthroplasty.

Patient expectations after primary total knee arthroplasty (TKA) continue to increase as the arthroplasty population becomes younger. Patients desire more than just pain relief, function, and the ability to return to higher level activities after TKA. Quadriceps muscle function and strength are critical determinants of this outcome. Many factors, including patient specific issues, surgical technique, and implant design, affect this function after TKA. This article will review our current understanding of quadriceps muscle function after TKA and the factors under the surgeon's control to achieve the best outcome.