title: Radiologic prevalence of advanced lateral C1-C2 osteoarthritis.
abstract: METHODS
  The lateral C1-C2 (atlantoaxial) joints were evaluated retrospectively in 355 patients referred for radiographs of the paranasal sinuses.
  
  
  OBJECTIVE
  To determine the radiologic prevalence of advanced lateral atlantoaxial osteoarthritis.
  
  
  BACKGROUND
  Previous studies have shown a relation between atlantoaxial osteoarthritis and referred pain in the suboccipital region. However, the radiologic prevalence of this degenerative disorder is unknown.
  
  
  METHODS
  Five hundred radiographs of the paranasal sinuses were evaluated retrospectively. Both lateral atlantoaxial joints were clearly visible on occipitofrontal projections in 355 examinations. Each lateral atlantoaxial joint was considered severely degenerated when advanced narrowing or obliteration of the joint space, subchondral sclerosis, and/or osteophytosis were present.
  
  
  RESULTS
  Atlantoaxial osteoarthritis was found in 4.8% of the patients. The radiologic prevalence of advanced degenerative changes at the lateral atlantoaxial joint(s) was found to increase with age, ranging from 5.4% in the sixth decade to 18.2% in the ninth decade of life.
  
  
  CONCLUSIONS
  Because advanced degenerative changes at the lateral atlantoaxial joints can cause suboccipital neck pain, these findings should be included in the differential diagnosis in older patients with this symptom.
authors.affiliation: Department of Radiology, St Antonius Hospital, Nieuwegein, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Zapletal
authors.forename: J C
authors.initials: JC
authors.lastname: de Valois
mesh_terms: D000368:Aged; D000375:Aging; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D019547:Neck Pain / Q000209:etiology; D010003:Osteoarthritis / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology*; D015995:Prevalence; D011859:Radiography; D013122:Spinal Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000453:epidemiology