Femoral fit predicts radiologic changes, but not clinical results, in Mallory-head total hip arthroplasties.

We prospectively studied the clinical and radiologic results of three groups of patients: 89 patients who had standard primary total hip replacements; 63 patients with hip dysplasia who had primary total hip replacements; and 48 patients who had revision total hip replacements. We studied the differences in clinical and radiologic behaviors of a titanium hydroxyapatite-coated stem with variations in the tightness of fit of the prosthesis in the femoral canal, operative group, stem size, grade of osteoporosis, and morphometric features of the femur. The clinical results in all three groups are slightly favorable for the standard primary group. Pain relief and stem survival in the three groups were similar to those reported in other studies regarding cementless prostheses. Nontight femoral fit significantly positively influenced the development of cancellous densification; however, the presence of osteoporosis also contributed to the formation of cancellous densification. Only tight femoral canal fit significantly positively influenced the development of cortical thickening independent of other parameters. There was no correlation between clinical parameters and the radiologic phenomena in either of the groups.