FEMORAL HEAD PERFUSION DURING HIP RESURFACING ARTHROPLASTY – A COMPARISON BETWEEN TWO APPROACHES

Abstract

Aim: Avascular necrosis of the femoral head is believed to 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 April 2006. Patients were divided into two groups according to approach. An equal number of operations were performed by two different surgeons; one using the extended posterior approach and the other an anterolateral approach. Intravenous cefuroxime was administered in every case following capsulectomy 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.

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

Conclusion: 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.