This prospective study was aimed to evaluate the incidence of osteonecrosis in Thai patients with
fracture neck of femur. Forty-three patients who had sustained fracture were enrolled in the present study. The
overall incidence of osteonecrosis was 72.1%. Incidence of osteonecrosis was 53.3% among patients who
underwent surgery within 1 week after injury and 82.1% among those who underwent surgery after that time
but there was no statistical difference (p-value = 0.07. Regarding displacement of fracture, the present study
found the incidence of osteonecrosis was 100% among patients with undisplaced (Garden type 1 and 2)
fractures and 60.0% and 76.9%, respectively among those with displaced fractures (Garden type 3 and 4).
Most histological changes according to Ficat and Arlet Method of undisplaced fractures were stage 1 and 2
and the displaced fracture was stage 2. It reveals a high rate of osteonecrosis following fracture neck of femur
but mostly in early reversible change. There was no significant statistical difference regarding age, duration,
type of fracture, and co-morbidity.

Keywords: Osteonecrosis, Fracture neck of femur