FEMORAL HEAD PERFUSION DURING HIP RESURFACING ARTHROPLASTY – A COMPARISON BETWEEN THE ANTEROLATERAL & POSTERIOR APPROACHES

Abstract

Introduction: Avascular necrosis of the femoral head may play a role in failure of the femoral component in metal on metal hip resurfacing arthroplasty. The purpose of our study was to determine, prospectively, femoral head perfusion during hip resurfacing arthroplasty in the posterior and anterolateral approaches.

Methods: 20 hip resurfacing arthroplasties were performed in 19 patients between September 2005 and March 2006 by two different surgeons; one using the extended posterior approach and the other an anterolateral approach. There were an equal number of procedures for each approach. 1.5 gms of intravenous cefuroxime was administered following caspsulectomy and relocation of the femoral head. After 5 minutes the femoral head was dislocated and prepared as routine for the operation. Bone from the top of the femoral head and reamings were sent for assay to determine the concentration of cefuroxime. The average time taken to prepare the femur and take samples was 8.5 minutes.

Results: The concentration of cefuroxime in bone was significantly greater when using the anterolateral approach (mean 15.7mg/kg; CI 12.3 – 19.1) compared to the posterior approach (mean 5.6mg/kg; CI 3.5 – 7.8; p< 0.001). In one patient, who had the operation through a posterior approach, cefuroxime was undetectable.

Discussion: The posterior approach is associated with a significant reduction in the blood supply to the femoral head during hip resurfacing arthroplasty. This may be a cause for avascular necrosis and potential failure of the femoral component in this procedure.