Answer: fracture of the ceramic femoral head

Discussion
The patient was relatively heavy, which may have been a contributing factor. At the time of the revision, the femoral component was found to be well fixed. The authors chose to place a ceramic head onto the well fixed stem in light of the history of extensive polyethylene wear. Precise matching of the taper inside the femoral head and the taper of the trunnion of the femoral stem may be important in order to avoid areas of stress concentration. The authors believe that an unrecognized defect on the existing taper may have contributed to the fracture of the ceramic head. The use of a ceramic femoral head on an existing taper at the time of a revision arthroplasty probably should be avoided as minor, unrecognizable flaws on the taper may lead to the formation of cracks in the ceramic with subsequent fracture.

Pulliam, IT, Trousdale, RT: Fracture of a ceramic femoral head after a revision operation. A case report. J Bone Joint Surg Am. 1997;118-9.