[Erosion with loosening of an aluminum oxide ceramic acetabulum. Case report]

The arthrodised hip of a 52 year-old female patient that had been absolutely trouble free for 9 years was remobilised by implanting a Mittelmeier, Autophor prosthesis (Al2O3 socket, Al2O3 head). Two years later, the hip joint had to be revised because of loosening of the socket. Since the shaft of the prosthesis was still firmly anchored within the femur, only the socket und the head were replaced. About three years following this revision, signs of loosening of the acetabular component again developed. Finally 4 1/3 years after the first revision (6 1/3 years after primary implantation) the hip was again revised. A polyethylene socket was then cemented into an acetabulum supporting shell and the prosthesis shaft furnished with a ceramic head of 32 mm diameter. Possible disadvantages of ceramic-ceramic bearing surfaces in patients with an altered bone structure of the pelvis and with a high risk of subluxation, due to weakened pelvi-trochanter muscles, are discussed.