title: Clinical analysis of osteonecrosis of the femoral head induced by steroids.
abstract: OBJECTIVE
  To explore the clinical characteristics of osteonecrosis of the femoral head (ONFH) induced by steroids.
  
  
  METHODS
  From January 2000 to October 2009, 497 hips in 270 cases of ONFH induced by steroids were studied. A questionnaire was administered when the patients were admitted; the questions concerned the underlying disease, duration of steroid usage, total dosage of steroid, incubation period (time interval between commencement of steroid therapy and onset of pain), severity of pain, location of initial complaint, primary diagnosis, time lag from onset of pain to final diagnosis and physical signs when admitted. The correlations between pain and Association Research Circulation Osseous (ARCO) stage, bone marrow edema (BME) and lesion size were analyzed.
  
  
  RESULTS
  The median of time between commencing steroid medication and developing ONFH for the 269 cases was 18 months (range, 2-384 months). 78.82% cases presented with pain within three years of steroid initiation, only 10.41% patients first complained of pain six or more years after commencing steroid therapy. Fifty-six cases (20.82%) were misdiagnosed, lumbar disorders being the most frequent misdiagnoses. 79.29% of symptomatic hips presented with abnormal physical tests. Of 420 symptomatic hips, 166 hips were type C1, 223 hips type C2; 299 hips had collapsed; and there was BME in 209 hips.
  
  
  CONCLUSIONS
  Most patients with ONFH induced by steroids complained of pain within 3 years of commencing steroid therapy. Pain was associated with lesion size, collapse and BME. Atypical location of pain, failure to perform a physical examination and MRI findings were the main causes of misdiagnoses.
authors.affiliation: Department of Orthopaedic Surgery, Affiliated Hospital of Xuzhou Medical College, Xuzhou, China. zhjianzh@sina.com
authors.forename: Feng-chao
authors.initials: FC
authors.lastname: Zhao
authors.forename: Zi-rong
authors.initials: ZR
authors.lastname: Li
authors.forename: Kai-jin
authors.initials: KJ
authors.lastname: Guo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005271:Femur Head Necrosis / Q000139:chemically induced* / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000209:etiology; D012189:Retrospective Studies; D012307:Risk Factors; D057566:Self Report; D013256:Steroids / Q000008:administration & dosage / Q000009:adverse effects*; D013997:Time Factors; D055815:Young Adult
chemical_list: D013256:Steroids