Extensor mechanism complications following total knee arthroplasty.

Patellofemoral complications are avoided by careful patient selection, proper implant design, and correct surgical technique. The patient with an extensor mechanism complication should be carefully evaluated for femoral and tibial component positioning, especially rotational alignment. Management of the extensor mechanism complication should be directed at its cause and may necessitate revision of the entire arthroplasty. Isolated revision of a patellar implant should only be performed once satisfactory alignment of the femoral and tibial components has been confirmed.