Avascular necrosis after internal fixation of intracapsular hip fractures; a study of the outcome for 1023 patients.

We prospectively studied 1023 patients who sustained an intracapsular hip fracture that was treated with internal fixation using contemporary methods. The overall incidence of avascular necrosis (AVN) was 6.6%. AVN was less common for undisplaced (4.0%) than for displaced fractures (9.5%) and in men (4.9%) than women (11.4%) who had a displaced fracture. The incidence of AVN for those aged less than 60 years and who sustained a displaced fracture was 20.6%, compared to 12.5% for those aged 60-80 years and 2.5% for those aged more than 80 years. Our study showed an increased risk of AVN with younger age and in females with a displaced fracture. We found no association between the incidence of AVN and the interval between injury to surgery.