Avascular necrosis of femoral head after gamma-nailing for unstable intertrochanteric fractures.

We reported on 7 cases of avascular necrosis of the femoral head after treatment of an unstable intertrochanteric fracture with the Asian Pacific gamma-nail. The incidence was about 1.16% (7 of 604) in our series. Good reduction and good implant position were achieved in all 7 men. Avascular necrosis was found about 6 months to 3 years after the initial operation, and all the fractures were solidly united at the final diagnosis. The possible etiologies were initial high energy trauma and combining basal neck fracture and iatrogenic damage of the blood supply to the femoral head.