Although numerous studies describe the clinical characteristics of idiopathic osteonecrosis of the femoral head (ONFH) in specific study populations, these have not been confirmed in countrywide studies.
Department of Public Health, Osaka City University Faculty of Medicine, 1-4-3, Asahi-machi, Abeno-ku, Osaka, 545-8585, Japan. wakaba@med.osaka-cu.ac.jp