Massive femoral osteolytic lesion secondary to disengagement of a total knee tibial locking pin: case report.

The Anatomic Modular Knee (AMK; Depuy, Warsaw, Ind) was one of the first designs to incorporate a modular locking mechanism for the tibial insert; fixation was secured using a screw-in tibial tray-locking pin. This case report describes a patient who presented with instability and worsening knee pain 15 years following a primary total knee arthroplasty using the AMK prosthesis. Radiographs and intraoperative assessment revealed proximal migration of the tibial tray-locking pin into the medial femoral condyle resulting in a large osteolytic defect.