HEMI- VERSUS FULL SURFACE ARTHROPLASTY FOR OSTEONECROSIS OF THE HIP.

Abstract

Fifty-six hips, mean age 40.4 underwent surface arthroplasty (SA) and twenty-eight hips, mean age 37.2 underwent hemiresurfacing (HSR). Diagnosis was osteo-necrosis in all. UCLA hip function and activity score, SF-12 physical, and Harris Hip score were significantly (p< 0.05) better for SA versus HSR. However, 2 SA were revised to THR, and 5 had evidence of femoral loosening. There was no evidence of femoral loosenings in the hemiresurfacing group. The median femoral component size was significantly larger in HSR than SA. Although the functional results are inferior with HSR, patients are at greater risk of femoral loosening with the full surface arthroplasty.

To determine if differences in outcome exist between HSR and MMSA at five years of follow-up in a group of patients with Ficat Stage III and IV osteonecrosis.

Treatment of osteonecrosis of the hip in the young adult still remains a challenge. The continued use of conservative prosthetic solutions should help minimize the morbidity of revision hip surgery.

Although the functional clinical outcome of MMSA is superior to HSR, patients are at greater risk of femoral loosening. Use of a larger femoral component in MMSA may decrease the risk of femoral loosening.

Eighty-four hips with osteonecrosis were treated with a resurfacing implant: fifty-six with a metal-metal SA, mean age 40.4 and twenty-eight, mean age 37.2 with a hemiresurfacing when the acetabular cartilage was minimally damaged. Male/female ratio was 73%/27% for HSR and 87%/13% for MMSA. Mean follow-up of 4.5 years, UCLA hip scores were significantly (p< 0.05) better for MMSA versus HSR for function (9.3 vs. 7.9) and activity (6.8 vs. 5.5) but not for pain (9.3 vs.8.6) and walking (9.5 vs. 9.0). SF-12 scores were comparable for the mental component but significantly better in the MMSA group (48.4 vs. 38.1, p= 0.001) for the physical component. Harris Hip Score was significantly better for MMSA (92.3 vs. 83.3, p=0.001). 2 MMSA were revised to THR, and five presented with evidence of femoral loosening. There was no evidence of femoral loosenings in HSR. Median femoral component size was significantly larger for HSR (50.0 vs. 46.0, p= 0.001).