title: Multicentric epidemiologic study on six thousand three hundred and ninety five cases of femoral head osteonecrosis in China.
abstract: OBJECTIVE
  Osteonecrosis of femoral head (ONFH) is a common joint disease with high morbidity in mainland China. We performed a retrospective case investigation based on the widest range of patients ever to reveal the demographic and clinical characteristics of ONFH in mainland China.
  
  
  METHODS
  We collected data from hospitalized patients of nine large tertiary hospitals in China, focusing on the aetiology of ONFH. Medical records and self-design questionnaires were used to collect data. We determined the patients' aetiology according to established guidelines and categorized patients into different subgroups. We further analysed the underlying illness of the steroid-induced osteonecrosis of femoral head.
  
  
  RESULTS
  A total of 6,395 patients with complete medical records were included in the study. The age (mean ± SD) of the patients was 46.45 ± 13.80 years. Males dominate with 70.1 % of all ONFH patients. In all the ONFH patients, 24.1 % are steroid induced, 30.7 % are alcoholic, 16.4 % are traumatic and 28.8 % are idiopathic. Among steroid-induced osteonecrosis of femoral head patients, 546 patients have autoimmune disorder (46.63 %), which is the most common underling illness, among these, the most common disease is systemic lupus erythematosus (SLE).
  
  
  CONCLUSIONS
  The most common age when ONFH occurs is between 40 and 50 years old. Male patients developed ONFH 3.4 years earlier than female patients. The number of the male patients is greater than the female, reaching the overall gender proportion of 7:3. Autoimmune disease is the primary cause of steroid-induced ONFH, among which SLE is the most common disease.
authors.affiliation: Department of Orthopaedics, Peking Union Medical College Hospital, No.1 Shuai-fu-yuan, Wang-fu-jing, Beijing, 100730, China.
authors.forename: Liqiang
authors.initials: L
authors.lastname: Cui
authors.affiliation: Department of Orthopaedics, Peking Union Medical College Hospital, No.1 Shuai-fu-yuan, Wang-fu-jing, Beijing, 100730, China.
authors.forename: Qianyu
authors.initials: Q
authors.lastname: Zhuang
authors.affiliation: Department of Orthopaedics, Peking Union Medical College Hospital, No.1 Shuai-fu-yuan, Wang-fu-jing, Beijing, 100730, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Orthopaedics, Peking Union Medical College Hospital, No.1 Shuai-fu-yuan, Wang-fu-jing, Beijing, 100730, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Jin
authors.affiliation: Department of Orthopaedics, Peking University Third Hospital, North Garden Rd No. 49, Haidian District, Beijing, 100191, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedics, The First Teaching Hospital of Xinjiang Medical University, South Liyushan street No. 137, Wulumuqi, Xinjiang Province, 830054, China.
authors.forename: Li
authors.initials: L
authors.lastname: Cao
authors.affiliation: Department of Orthopaedics, Peking University People's Hospital, No. 11 Xizhimen South Street, Xicheng District, Beijing, 100044, People's Republic of China.
authors.forename: Jianhao
authors.initials: J
authors.lastname: Lin
authors.affiliation: Department of Orthopaedics, The First Affiliated Hospital of Zhejiang University, Qingchun street No. 79, Hangzhou, Zhejiang Province, 310003, China.
authors.forename: Shigui
authors.initials: S
authors.lastname: Yan
authors.affiliation: Department of Orthopaedics, China-Japan Friendship Hospital, 2 Yinghua Dongjie, Hepingli, Beijing, 100029, China.
authors.forename: Wanshou
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Orthopaedics, The First Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine, No. 16 Airport Street, Guangzhou, 510405, China.
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.affiliation: Department of Orthopaedics, West China Hospital, Sichuan University, No. 37, Guoxue Street, Wuhou district, Chengdu, Sichuan, 610041, China.
authors.forename: Fuxing
authors.initials: F
authors.lastname: Pei
authors.affiliation: Department of Orthopaedics, Beijing Jishuitan Hospital, No. 31 Eastern Xinjiekou Street, Xicheng district, Beijing, 100035, China.
authors.forename: Yixin
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Orthopaedics, Peking Union Medical College Hospital, No.1 Shuai-fu-yuan, Wang-fu-jing, Beijing, 100730, China. xsh_weng@163.com.
authors.forename: Xisheng
authors.initials: X
authors.lastname: Weng
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D005260:Female; D005270:Femur Head / Q000473:pathology*; D005271:Femur Head Necrosis / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012307:Risk Factors; D017678:Sex Distribution; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Etiology; Osteonecrosis of femoral head; Risk factor