Periprosthetic fracture, specifically femoral neck fracture, is the most common cause of early revision less than 20 weeks following surgery.
The rate of femoral neck fractures following hip resurfacing varies, but most literature reports a rate of 1%. A majority of these fracture happen in the early post-operative period and are the most frequent cause of revision surgery within several months following surgery. The cause is usually multifactorial, but placing the femoral implant in varus, osteonecrosis, and notching have been proven risk factors for fracture.
Little el al report on 377 patients undergoing hip resurfacing. 13 required revision including 8 for fracture of the femoral neck and 3 for loosening of a component. Evidence of osteonecrosis was seen in two of these cases, leading the authors to believe it may contributed to fracture.
Illustration A shows a comparison of a typical total hip replacement and a hip resurfacing arthroplasty. Illustration B shows notching of the femoral neck, a known cause of femoral neck fracture following hip resurfacing. Illustration C shows a femoral neck fracture in a patient with a hip resurfacing.
Little CP, Ruiz AL, Harding IJ, McLardy-Smith P, Gundle R, Murray DW, Athanasou NA. Osteonecrosis in retrieved femoral heads after failed resurfacing arthroplasty of the hip. J Bone Joint Surg Br. 2005 Mar;87(3):320-3.
PMID:15773638 (Link to Abstract)