title: The clinical picture of atlantoaxial subluxation changes when atlantoaxial impaction develops.
abstract: OBJECTIVE
  The objective of the study was to evaluate the clinical picture of rheumatoid patients with anterior atlantoaxial subluxation (aAAS), atlantoaxial impaction (AAI) or their combination.
  
  
  METHODS
  There were 156 patients. aAAS was diagnosed from standard lateral-view cervical spine radiographs during flexion. AAI was diagnosed from radiographs by the Sakaguchi-Kauppi method. Cervical range of motion was measured and patients' functional disability evaluated. Intensity of the neck pain was evaluated. Clinical data was collected from patient records.
  
  
  RESULTS
  aAAS was detected in 138 (88%) of all patients and AAI in 69 (44%), respectively. Forty (48%) patients with severe aAAS had additional AAI, whereas 11 (21%) patients with slight or moderate aAAS had AAI. Range of the neck motion (ROM) was lower in patients with AAI compared with patients with aAAS alone. Rotation (p<0.001) and lateral flexion (p=0.006) were more limited in patients with AAI. Practically normal rotation (> or =120 degrees) was seen in 16 (18%) of patients with aAAS and four (6%) of patients with AAI. Patients with AAI without aAAS had both limited mobility and high intensity of neck pain.
  
  
  CONCLUSIONS
  Patients with atlantoaxial disorders may be painless. Neck pain, which is induced in upright position and relieved during bed rest, is most often due to AAI. ROM may be normal in plain aAAS while rotation is typically reduced when AAI develops.
authors.affiliation: Department of Rheumatology, Rheumatism Foundation Hospital, Pikijarventie, 18120 Heinola, Finland. erja.lehto@uta.fi
authors.forename: Erja M
authors.initials: EM
authors.lastname: Lehto
authors.forename: Sirkka
authors.initials: S
authors.lastname: Heikkilä
authors.forename: Hannu
authors.initials: H
authors.lastname: Kautiainen
authors.forename: Markku J
authors.initials: MJ
authors.lastname: Kauppi
mesh_terms: D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D019547:Neck Pain / Q000000981:diagnostic imaging / Q000453:epidemiology; D015995:Prevalence; D011859:Radiography; D016059:Range of Motion, Articular; D012720:Severity of Illness Index