title: Isolated inflammatory coxitis associated with protrusio acetabuli: a new form of juvenile idiopathic arthritis?
abstract: BACKGROUND
  Isolated hip disease in the context of chronic childhood inflammatory arthritis is uncommon. This paper reports 14 children who presented to the rheumatology and orthopaedic departments of our hospitals with severe hip symptoms, and who continued to have primarily hip disease throughout their clinical course. Our aim was to characterize and present the relevant demographic, clinical, investigational, treatment and outcome data from the above cohort.
  
  
  METHODS
  All paediatric cases with the diagnosis of protrusio acetabuli, Otto pelvis or idiopathic chondrolysis who were seen in the past 15 yr at Great Ormond Hospital and Middlesex Hospital in London were identified and their case notes were searched retrospectively for relevant information.
  
  
  RESULTS
  In 11 cases, the disease progressed to involve no joints other than the contralateral hip. None were considered to have a specific subtype of juvenile idiopathic arthritis (JIA) and all tested were negative for HLA-B27. Elevation of serum inflammatory markers was variable. Protrusio acetabuli was the predominant radiological feature. There were definite inflammatory changes on the gadolinium-enhanced magnetic resonance imaging study in all patients who had this procedure performed (seven cases). Microbiological investigations were all consistently negative. Severe hip disease resulted in considerable ongoing symptoms and disability. Six cases were treated with disease-modifying anti-rheumatic drugs. Total hip replacement has been required in four patients to date, with major functional improvement.
  
  
  CONCLUSIONS
  These cases represent severe and disabling primary hip disease with considerable clinical and investigational inflammatory features. Such a mode of presentation has not been described previously in the context of childhood chronic inflammatory arthritides, and may represent a separate oligoarthritis subtype of JIA.
authors.affiliation: Department of Rheumatology, Great Ormond Street Hospital, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Adib
authors.forename: K L
authors.initials: KL
authors.lastname: Owers
authors.forename: J D
authors.initials: JD
authors.lastname: Witt
authors.forename: C M
authors.initials: CM
authors.lastname: Owens
authors.forename: P
authors.initials: P
authors.lastname: Woo
authors.forename: K J
authors.initials: KJ
authors.lastname: Murray
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001171:Arthritis, Juvenile / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D002648:Child; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D010146:Pain / Q000503:physiopathology; D011859:Radiography; D012189:Retrospective Studies
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D018501:Antirheumatic Agents