Epidemiology of nontraumatic osteonecrosis of the femoral head in Japan

Abstract

Objectives. To elucidate the epidemiology of nontraumatic osteonecrosis of the femoral head (ONFH), and to estimate the annual incidence rate in Japan.

Methods. We examined, over the course of 3 years, personal records and radiographic images from the national registry of documents used for the study of nontraumatic ONFH in patients in Aichi Prefecture, Japan (population: 7.4 million). Those patients not meeting the diagnostic criteria according to the Japanese Investigation Committee for nontraumatic ONFH were excluded from this study.

Results. A total of 285 out of the 327 patients who applied for the national registration of nontraumatic ONFH during the 3-year study met the diagnostic criteria for personal records, radiographic images, and magnetic resonance images. Forty-two patients (12.8%) were not considered to have nontraumatic ONFH. The mean age of patients was 50.4 years, and the male-female ratio was 2.1:1. Nontraumatic ONFH was steroid-induced in 135 cases (47.4%), alcohol-associated in 87 cases (30.5%), steroid-induced and alcohol- associated in 14 cases (4.9%), and idiopathic in 49 cases (17.2%).

Conclusions. The age-adjusted annual incidence of nontraumatic ONFH in Aichi Prefecture was estimated at 138.5 patients.Thus the annual incidence rate in Japan (population 128 million) was 1.91/100,000.

Keywords:

• Epidemiology
• Femoral head
• Incidence rate
• Nontraumatic osteonecrosis

Acknowledgments

The senior authors (Y. Hasegawa and T. Seki) have received funding from a research grant for the Research on Idiopathic Osteonecrosis of the Femoral Head and the Research on Epidemiology of Intractable Diseases from the Ministry of Health, Labor and Welfare of Japan.

Conflict of interest

N. Ishiguro has received research funding from Takeda, Mitsubishi-Tanabe, Astellas, Chugai, Abbott, Bristol-Myers Squibb, Eisai, Daiichi Sankyo Company Ltd,Janssen, Kaken and Pfizer and has served on speaker bureaus for Daiichi Sankyo Company Ltd, Takeda Pharmaceutical Co Ltd, Hisamitsu Pharmaceutical Co Inc, Otsuka Pharmaceutical Co Ltd, Taisho Toyama Pharmaceutical Co Ltd, Kaken Pharmaceutical Co Ltd, Eisai Co Ltd, Janssen Pharmaceutical K.K, Bristol-Myers Squibb, Abbott Japan, Chugai Pharmaceutical Co Ltd, Mitsubishi Tanabe Pharmaceutical, UCB Japan, Astellas Pharma Inc., and Pfizer Japan Inc.