Review Question - QID 6058

The patient has a femoral neck fracture following hip resurfacing placed in varus position.

Hip resurfacing is a controversial procedure with best outcomes seen in young males with good bone stock. The two most common modes of failure following hip resurfacing are femoral neck fracture and aseptic loosening. Risk factors for femoral neck fracture include femoral neck notching, osteoporotic bone, large amounts of femoral head bone loss, femoral neck impingement, female sex, and varus positioning of the femoral component. Awareness of those risk factors that are surgeon dependent is important to decrease rates of failure. Following a periprosthetic femoral neck fracture conversion to total hip arthroplasty is recommended.

Gabriel et al. present a case of femoral stem fracture following hip resurfacing in a 15-year-old male. They conclude that in patients with lesions of the majority of the femoral head surgeons should consider using an implant with a substantial femoral neck.

Amstutz et al. present their results of a series of 600 metal on metal hip resurfacing arthroplasties. They found 5 (0.83%) femoral neck fractures all of which some form of structural and/or technical risk factor was present. They conclude that understanding the factors that contribute to femoral neck fractures may limit their prevalence.

Figure A shows a left hip resurfacing in varus alignment. Figure B shows a subsequent radiograph with periprosthetic femoral neck fracture. Illustration A shows a conversion to a total hip arthroplasty following periprosthetic femoral neck fracture.

Incorrect Answers:
Answer 1: There are no signs of infection based on this vignette.
Answer 2: Female, not male gender is thought to be associated with a higher risk of femoral neck fractures following hip resurfacing.
Answer 4: Osteoporotic bone is a risk factor for fracture following hip resurfacing, not sclerotic bone.
Answer 5: Older age may be associated with higher risk of femoral neck fracture.