Abstract
Bone resorption of the medial femoral neck was measured in 84 Charnley total hip arthroplasties of 11 males and 5 4 females, with an average age of 57.2 at operation. The average follow-up period was 11.7 years. Also measured were the position of the stem in the femoral canal, the thickness of the methylmetacrylate at the medial femoral neck, loosening of the socket, and the amount of socket wear. The average amount of bone resorption was 3.4 mm (range 0 to 33 mm) . Loosening of the socket was found in 15 cases. In 40 hips the stem position was valgus, in 42 hips it was neutral and in only 2 hips it was varus. The average thickness of bone cement was 4.6mm and the average socket wear was 1.3 mm. The amount of bone resorption was larger in the socket loosening group (p <0.02), and the coefficient of correlation between the amount of bone resorption and wear of the socket was 0.38 (p <0.001) . We think loosening of the socket and wear of the socket are major factors in bone resorption.
