Fatigue fractures of total knee prostheses - a cause of knee pain.

Femoral component fracture is a rarely reported complication in cemented total knee arthroplasty. We present a case of new- onset acute unresolving knee pain caused by fatigue fracture of the medial condyle of the femoral component 11 years after primary total knee replacement. This was identified and subsequently revised with a revision prosthesis. The patient had an uneventful recovery, and his symptoms resolved. Considering that the aging population and the rate of obesity are increasing and that there is an exponential increase in the number of joint arthroplasties; this case sheds light on a rare cause of acute non-traumatic knee pain following knee arthroplasty that could be present with or without evidence of osteolysis. We also review the literature of cases of fractured cemented and uncemented knee replacements and discuss the causes proposed.