[Hemiarthroplasty and total hip arthroplasty for idiopathic osteonecrosis of the femoral head].

Patients with idiopathic osteonecrosis of the femoral head (ION) are relatively younger (usually in their 30s to 50s) than those with osteoarthrosis (OA) , and usually have higher activity levels. When the necrotic area is large, or when advanced OA has developed, hemiarthroplasty or total hip arthroplasty (THA) are considered. When indicating these implant surgeries, age and life style of patients should be considered in selecting type of surgery and implant. In our previous study, THA was superior in durability to hemiarthroplasty in the entire series of ION patients and in the patients with stage 2 or 3 ION (without secondary OA) . As implants used for these surgeries have been improved, we are currently monitoring these implant surgeries with special interest in their durability.