The Effect of Femoral Neck Notching with the Birmingham Mid-Head Resection

The new generation of metal-on-metal hip resurfacing is becoming an increasingly popular alternative to total hip replacement in the younger and more active patient. Mid-term survivorship figures for osteoarthritic patients are comparable to that of patients receiving a total hip arthroplasty. However, individuals receiving a hip resurfacing for aetiologies other than OA, such as avascular necrosis, experience poorer outcomes and higher revision rates (1-2). The Birmingham Mid-Head Resection (BMHR, Orthopaedics, Warwick, United Kingdom) (Figure 1) is designed as a short-stem alternative to hip resurfacing for patients presenting with compromised or unsuitable femoral head anatomy. The BMHR shares the same advantages of proximal femoral bone conservation and ease of revision as that of a standard hip resurfacing. However, retention of the femoral neck bears with it the risk of femoral neck fracture. Several risk factors for femoral neck fracture with traditional hip resurfacing have been identified including femoral neck notching and varus implant alignment. It is not known however, if these fracture risks pose the same hazard to a mid-head resection arthroplasty. The purpose of the current study was to investigate the effect of superior femoral neck notching with the BMHR.