Extensor mechanism complications after total knee arthroplasty.

The patellofemoral joint is an important source of pain and complications following total knee arthroplasty. Anterior knee pain, patellar instability, fracture, rupture of the extensor mechanism, and a variety of miscellaneous problems affecting the patella can adversely affect the results of a total knee arthroplasty. Because patellofemoral complications after total knee arthroplasty often occur because of problems with patient selection, implant design, and surgical technique, it is important for orthopaedic surgeons treating patients with extensor mechanism complications after total knee arthroplasty to evaluate the entire knee replacement and base treatment on the etiology of the complication and not just the complication itself.