title: The prevalence of osteoarthritis of the sternoclavicular joint on computed tomography.
abstract: BACKGROUND
  Symptomatic disorders around the sternoclavicular joint (SCJ) are relatively uncommon. Previous cadaveric and radiographic studies have suggested that asymptomatic osteoarthritic changes are relatively common, progressively increasing with age. The purpose of this study was to determine the prevalence of SCJ osteoarthritis in the general population using computed tomography (CT) scans.
  
  
  METHODS
  We assessed 464 SCJs in 232 patients undergoing a standardized axial CT scan of the thorax including both SCJs, across a range of ages from the second to tenth decade. The scans were undertaken for multiple clinical indications; however, none were obtained to investigate SCJ pathology. The predominant changes investigated were for the features associated with osteoarthritis including the presence of osteophytes, subchondral cysts, and subcortical sclerosis.
  
  
  RESULTS
  The CT scans of 244 SCJs (53%) in 137 patients (59%) showed at least 1 sign of osteoarthritis. No patients younger than 35 years had any features of osteoarthritis. Osteoarthritic changes were present in 89.6% of patients older than 50 years compared with 9.1% younger than this age. All patients above the age of 61 had at least 1 feature of osteoarthritic changes on at least 1 side of the SCJ. Increasing prevalence was noted with increasing age both in the percentage of SCJs showing any positive signs of osteoarthritis and in the severity of osteoarthritis.
  
  
  CONCLUSIONS
  SCJ osteoarthritis is a very common incidental finding on CT scans, particularly with increasing age. This should be taken into consideration when using a CT scan to assess a patient with symptomatic SCJ pathology.
authors.affiliation: Shoulder Unit, Trauma & Orthopaedic Department, Addenbrookes Hospital, Cambridge University Hospitals NHS Trust, Cambridge, UK. Electronic address: drcrlawrence@gmail.com.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Lawrence
authors.affiliation: Shoulder Unit, Trauma & Orthopaedic Department, Addenbrookes Hospital, Cambridge University Hospitals NHS Trust, Cambridge, UK.
authors.forename: Benjamin
authors.initials: B
authors.lastname: East
authors.affiliation: Shoulder Unit, Trauma & Orthopaedic Department, Addenbrookes Hospital, Cambridge University Hospitals NHS Trust, Cambridge, UK.
authors.forename: Abbas
authors.initials: A
authors.lastname: Rashid
authors.affiliation: Shoulder Unit, Trauma & Orthopaedic Department, Addenbrookes Hospital, Cambridge University Hospitals NHS Trust, Cambridge, UK.
authors.forename: Graham M
authors.initials: GM
authors.lastname: Tytherleigh-Strong
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015995:Prevalence; D013247:Sternoclavicular Joint; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Sternoclavicular joint; age; computed tomography; cysts; osteoarthritis; osteophytes; prevalence; sclerosis