title: Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study.
abstract: OBJECTIVE
  Is there concordance between hip pain and radiographic hip osteoarthritis?
  
  
  METHODS
  In this diagnostic test study, pelvic radiographs were assessed for hip osteoarthritis in two cohorts: the Framingham Osteoarthritis Study (community of Framingham, Massachusetts) and the Osteoarthritis Initiative (a multicenter longitudinal cohort study of osteoarthritis in the United States). Using visual representation of the hip joint, participants reported whether they had hip pain on most days and the location of the pain: anterior, groin, lateral, buttocks, or low back. In the Framingham study, participants with hip pain were also examined for hip pain with internal rotation. The authors analysed the agreement between radiographic hip osteoarthritis and hip pain, and for those with hip pain suggestive of hip osteoarthritis they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of radiographs as the diagnostic test.
  
  
  CONCLUSIONS
  In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of radiographic hip osteoarthritis for hip pain localised to the groin was 36.7%, specificity 90.5%, positive predictive value 6.0%, and negative predictive value 98.9%. Results did not differ much for hip pain at other locations or for painful internal rotation. In the Osteoarthritis Initiative study (n=4366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of definite radiographic hip osteoarthritis for hip pain localised to the groin was 16.5%, specificity 94.0%, positive predictive value 7.1%, and negative predictive value 97.6%. Results also did not differ much for hip pain at other locations.
  
  
  CONCLUSIONS
  Hip pain was not present in many hips with radiographic osteoarthritis, and many hips with pain did not show radiographic hip osteoarthritis. Most older participants with a high suspicion for clinical hip osteoarthritis (groin or anterior pain and/or painful internal rotation) did not have radiographic hip osteoarthritis, suggesting that in many cases, hip osteoarthritis might be missed if diagnosticians relied solely on hip radiographs.
  
  
  BACKGROUND
  See the full paper on thebmj.com for funding. The authors have no competing interests. Additional data are available from bevochan@bu.edu.
authors.affiliation: Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany St, Room X200, Boston, MA 02116, USA Department of Rheumatology, Boston University School of Medicine, Boston, MA, USA bevochan@bu.edu.
authors.forename: Chan
authors.initials: C
authors.lastname: Kim
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Nevitt
authors.affiliation: Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany St, Room X200, Boston, MA 02116, USA.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Niu
authors.affiliation: Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany St, Room X200, Boston, MA 02116, USA.
authors.forename: Mary M
authors.initials: MM
authors.lastname: Clancy
authors.affiliation: Department of Rheumatology, University of California, Davis, CA, USA.
authors.forename: Nancy E
authors.initials: NE
authors.lastname: Lane
authors.affiliation: Department of Rheumatology, University of California, San Francisco, CA, USA.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Link
authors.affiliation: Department of Rheumatology, Tufts Medical Center, Boston, MA, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Vlad
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, CA, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Tolstykh
authors.affiliation: Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany.
authors.forename: Pia M
authors.initials: PM
authors.lastname: Jungmann
authors.affiliation: Clinical Epidemiology Research and Training Unit, Boston University School of Medicine, 650 Albany St, Room X200, Boston, MA 02116, USA NIHR Manchester Biomedical Research Unit, Manchester, UK.
authors.forename: David T
authors.initials: DT
authors.lastname: Felson
authors.affiliation: Department of Radiology, Boston University School of Medicine, Boston, MA, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Guermazi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000000981:diagnostic imaging* / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D011237:Predictive Value of Tests; D015995:Prevalence; D011859:Radiography; D012307:Risk Factors; D006113:United Kingdom; D014481:United States