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

Abstract

Introduction: Dividing the short external rotators 2 cm from their insertion into the femur should preserve the deep branch of the medial femoral circumflex artery. Our aim was to determine, prospectively, femoral head perfusion during hip resurfacing arthroplasty comparing two posterior approaches.

Methods: 20 hip resurfacing arthroplasties were performed in 20 patients by two different surgeons between September 2005 and November 2006. Patients were divided into two equal groups according to approach. One surgeon used the extended posterior approach and the other a modified posterior 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: There was no statistical difference between the concentration of cefuroxime in bone when using the modified posterior approach (mean 5.6mg/kg; CI 3.6 – 7.8) compared to the extended posterior approach (mean 5.6; CI 3.5 – 7.8; p=0.95). In one patient, who had the operation through the posterior approach, cefuroxime was undetectable.

Discussion: The similarity in femoral head perfusion between approaches suggests the blood supply is further impaired by capsulectomy rather than by damaging the MFCA alone.