A comparison of osteonecrosis and osteoarthritis patients following total hip arthroplasty. A long-term follow-up study.

Between November 1969 and December 1983, 105 total hip arthroplasties were performed on 82 patients with a diagnosis of idiopathic osteonecrosis (ON). During the same period, 891 total hip surgeries were performed on 706 osteoarthritis (OA) patients. In order to statistically compare these two diseases, the records of each patient were examined for possible differences in bilaterality, sex, age, and acute postoperative complications including infections, pain, nonunions, and heterotopic bone (HB). Sixty-four ON hips and 615 OA hips (all with at least three years of follow-up data) were then evaluated for acetabular and femoral radiolucency, acetabular and femoral loosening, and pain. The same long-term complications were evaluated in some of these patients at five-, seven-, and ten-year follow-up periods. The ON patients were significantly younger than the OA patients (p less than .001). Bilateral involvement and male/female distributions were found to be similar. Except for HB, acute postoperative complications (zero to six months) were similar. Early HB surrounding one-third or more of the hip joint was statistically less in the ON patient population (p less than .001). No significant differences in long-term complications were found. However, a much higher death rate was found in ON patients (24%) as compared to OA patients (15%) (significant at p less than .07). This difference was not due to any postoperative complication or the hip arthroplasty itself, because both were the same in the two populations.