Unexpected finding of a fractured metal prosthetic femoral head in a nonmodular implant during revision total hip arthroplasty.

Though there are many reports of fractured femoral components after total hip arthroplasty; there are no reports of a fractured metal femoral head. This is a report of a fractured metal femoral head in a nonmodular total hip replacement discovered unexpectedly during revision total hip arthroplasty for acetabular failure. This surprise finding, which was not appreciated on preoperative x-rays, required unplanned extraction of a well-ingrown, fully porous coated cylindrical femoral stem. Though rare, fracture of the metal femoral head in a DePuy (Warsaw, Ind.) monoblock Anatomic Medullary Locking (AML) component is possible, and one cannot expect the fracture to be apparent on preoperative radiographs as the 2 pieces may not necessarily dissociate. As usual, the surgeon performing revision arthroplasty should be prepared to revise all components.