Avascular necrosis of the femoral head after intertrochanteric fractures

Objective: To determine factors that may influence the appearance of avascu lar necrosis after intertrochanteric fractures. Design: Retrospective. Setting: University hospital. Patients: Twelve patients between the ages of fifty-nine and eighty-eight w ho had developed avascular necrosis of the femoral head after treatment of an intertrochanteric femur fracture at our institution between 1976 and 199 5. Fractures were classified according to Kyle and Gustilo. There were thre e Type I, two Type II, six Type III, and one Type IV fractures. Main Outcome Measures: Risk factors for osteonecrosis, fracture pattern, su rgical influence, location of the nail within the femoral head, and valgus malalignment. Results: All fractures healed. Five patients had risk factors for osteonecr osis. Intertrochanteric fractures with a proximal fracture line appeared in five patients. The nail tip was situated in every quadrant of the femoral head. Valgus malalignment occurred in three cases. Conclusions: Avascular necrosis of the femoral head is an uncommon complica tion after intertrochanteric fractures. The pathogenesis is unknown, but in patients developing pain who have had intertrochanteric fractures, osteone crosis should be included in the differential diagnosis, especially in case s with risk factors for osteonecrosis or a proximal intertrochanteric fract ure line that perhaps disrupts the vascular anastomotic ring at the base of the femoral neck.