Bateman hemiarthroplasty component disassembly. A report of three cases of high-density polyethylene failure.

Mechanical failures occurred in three Bateman bipolar hemiarthroplasties in two patients. In all three occurrences, the disassembly of the bipolar prosthesis was caused by fracture of the polyethylene liner of the bipolar acetabular component. This caused the 22-mm head of the femoral component to separate and unlock from the acetabular component. Both patients have functional hips after replacement of the acetabular component with a new "self-centering" type. The mechanical design may predispose this bipolar hemiarthroplasty to disassemble.