OUTCOME OF UNCEMENTED FEMORAL STEMS FOR OSTEONECROSIS OF THE HIP

Introduction: Cementless total hip arthroplasty has been advocated for osteonecrosis of the femoral head (ONFH) as these patients are generally younger and more active than patients with osteoarthritis (OA). Since introduced in the early 1980’s, there have been several generations of cementless total hip prostheses. This study examined the outcome of the femoral stem of four generations of uncemented total hip prostheses. Materials and Methods: One hundred and fifty-eight hips in 135 osteonecrosis patients (71 men, 64 women) who had a mean age of 46 years (range, 17 to 83) were included. The total number of prostheses included: PCA™ (77), E Series™ (47), Meridian™ (18), and Citation™ (16) (all Stryker, Mahwah, New Jersey). The mean follow-up was 105.5 +/− 60.8 months (range, 20 to 257 months). As part of an ongoing IRB-approved study, data collected includes Harris Hip (HHS) and QOL scores, re-operations (including revisions), and complications. Results: The femoral components of 142 cases were not revised. These patients had a mean HHS of 86.3 +/− 13.2 points. Of the 15 revisions (9.6%), the primary reasons were loosening and/or significant osteolysis, but there was one infection and one chronic dislocation. The revisions included 10 PCA™ (13.0%) with a mean time to revision of 85 months (range, 25 to 132); 2 E Series™ (4.3%) with a mean time to revision of 85 months (2 cases in one patient; 68 and 101 months); 2 Meridian™ (11.1%) with a mean time to revision of 193 months (2 cases; 98 and 107 months); and 1 Citation™ (6.3%) with a time to revision of 30 months. The pooled revision rate of the 2 nd , 3rd, and 4 th generation was 5 of 80 (6.3%). Discussion: There were no significant difference in revision rates between the different generations of uncemented femoral components (Chi Square, p=.433). However, the revision rates for the later generations were lower than the earlier generations.