Anatomic study on the blood supply to the femoral head following hip resurfacing using the posterior approach

OBJECTIVES: The aim of this study was to investigate femoral head perfusion following cadaveric hip resurfacing using the posterior approach. METHODS: This cadaveric study involved injecting Higgins India ink into the common iliac arteries and evaluating the distribution of ink in the resurfaced heads using the modified Spalteholz technique. The study consisted of 2 parts. The 1st part involved utilisation of 22 cadaveric hips for establishing the injection and histological technique. The 2nd part of the study included 4 control cadaveric hips and 12 cadaveric hips with posterior approach hip resurfacing. Each specimen was divided into 15 zones (12 head zones and 3 neck zones) to evaluate detailed geographic distribution of dye-containing blood vessels. RESULTS: All 4 controls had good flow of ink to all head zones and the neck region. In all the resurfaced heads, there was good flow to all the neck zones. 6 resurfaced specimens had no dye flow to any of the head zones. In the remaining 6, dye-stained vessels were seen variably in the anterior and middle zones but were consistently absent in the posterior zones of the head. Zones representing the antero-inferior parts of femoral head had the maximum flow of ink, followed by zones representing middle-inferior parts. CONCLUSIONS: Posterior approach for hip resurfacing arthroplasty results in vascular insult to the femoral head, with posterior zones more affected than the anterior zones. The persistence of the dye in the intraosseous blood vessels of the neck and in anteroinferior head may be a source of revascularisation of the femoral head after posterior approach hip resurfacing.