TWO TO ELEVEN YEAR SURVIVAL OF METAL-METAL HIP RESURFACING IN FEMORAL HEAD OSTEONECROSIS.

Abstract

Introduction. Painful post-collapse femoral head osteonecrosis (AVN) continues to be a therapeutic challenge. Joint preserving surgery does not produce satisfactory results after femoral head collapse, making an arthroplasty almost inevitable. Does metal-metal resurfacing offer a conservative option that matches the consistent results of a stemmed THA in these patients?

Methods. 104 consecutive resurfacings (94 patients) performed for Ficat stage III/IV AVN were reviewed clinically, radiologically and with Oxford hip scores. Mean age at operation was 43.9 years. Aetiology included trauma (20%), steroids/chemotherapy (25%), alcohol abuse (8%), AVN secondary to Perthes’/SUFE (4%) and idiopathic (43%). Two types of devices were used a) McMinn Resurfacing Arthroplasty, HA-coated smooth uncemented cup and cemented femoral component and b) Birmingham Hip Resurfacing, porous HA cup and cemented femoral component.

Results. At 2 to 11.5 years (mean 7.7 years), there were seven (6.7%) failures: four from further femoral head collapse, two infections and one osteolysis, aseptic loosening. The cumulative survival at 11years is 90% (figure 1). Mean Oxford score at follow-up is 15.4. 55% participate in moderate to heavy work or participate in regular sporting activity.

Discussion. The results of any treatment modality in AVN are not as good as those in osteoarthritis. One reason is that the etiopathological factors that caused non-traumatic AVN (steroids etc) have the potential to cause continued femoral head damage. Post-traumatic patients need complex reconstructions and risk a higher failure rate. Those on immunosuppressants are prone to infections. The results of hip resurfacing in AVN in this series are no different from THRs in many published series. Metal-metal resurfacing is a good conservative option for post-collapse femoral head AVN and gives acceptable results if strict patient selection criteria are followed.