Total knee arthroplasty.

Over the past 15 years, total knee arthroplasty has evolved to a substantial degree with respect to both design and technique. Although initially it lagged well behind the "state of the art" for total hip arthroplasty, it now appears to have surpassed the older procedure, particularly with respect to durability. The management of severe deformities and the improvement of the eventual range of motion remain challenges, but both are being met with increasing success.