The treatment of the osteonecrosis in the acetabulum and femoral head after irradiation has not been well estabilished. The early failure of acetabular component after total hip arthroplasty (THA) is the main concern in osteonecrosis after irradiation.

Our study included 18 patients with post-radiation osteonecrosis of 26 hips who had a THA, mean age 54.2 years. Average irradiation dosage was 4611 cGy and interval between irradiation and primary total hip replacement was 64.3 months. The cementless acetabular components were used in 16 hips (group one) and acetabular reinforcement rings were used in 10 hips (group two: Muller cup 6 cases, Ganz cup 4 cases).

Acetabular loosenings were occurred at 8 of 16 hips (Group 1: 50%) during the mean follow-up 46 months. The cases of Muller cup (Group 2: 33%) was failed in 2 of 6 hips at postoperative 12 months and 22 months.

Although follow up duration is short and cases are small, the use of cemented cup with acetabular reinforcement ring was better than non-cemented cup for THA in irradiated hip in terms of preventive of early failure of acetabular component.