title: Frequency, imaging findings, risk factors, and long-term sequelae of distal clavicular osteolysis in young patients.
abstract: OBJECTIVE
  Atraumatic distal clavicular osteolysis (DCO) has been described in adult male weightlifters. Our purpose was to investigate the frequency, magnetic resonance imaging (MRI) characteristics, risk factors, and long-term sequelae of DCO in young patients.
  
  
  METHODS
  Individuals with atraumatic DCO were identified in a retrospective review of 1,432 consecutive MRI shoulder reports in patients between 13 and 19 years of age. MRI findings of DCO, association with athletic activity, short-term clinical outcome after 3-6 months, and long-term clinical and MRI outcome after 2 years were analyzed. A pre-MRI questionnaire assessed the patients' athletic history including overhead activity and weightlifting.
  
  
  RESULTS
  At a mean age of 15.9 years, 6.5 % (93/1432) of patients had atraumatic DCO, and 24 % were females. The combination of an overhead sport (basketball, volleyball, tennis, swimming) and supplemental weight training was a risk factor for DCO (odds ratio = 38, p = 0.01). Ninety-three percent of patients responded to conservative therapy. On follow-up imaging, 71 % of DCO patients had acromioclavicular (AC) joint osteoarthritis (vs. 35 % in controls, p = 0.006); 79 % had flattening of the distal clavicle and interval widening of the AC joint to a mean of 5.0 mm (compared to 2.4 mm in controls, p < 0.001). Severity of DCO edema was associated with pain (p < 0.02) at initial presentation and with AC joint osteoarthritis (p = 0.004) on follow-up.
  
  
  CONCLUSIONS
  In athletic teenagers, the combination of weightlifting and overhead activity is a risk factor for atraumatic DCO, and females are affected in 24 %. Long-term sequelae include widening of the AC joint and AC joint osteoarthritis.
authors.affiliation: Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Thomas Jefferson University, 132 South 10th Street, Philadelphia, PA, 19107, USA, johannes.roedl@jefferson.edu.
authors.forename: Johannes B
authors.initials: JB
authors.lastname: Roedl
authors.forename: Mika
authors.initials: M
authors.lastname: Nevalainen
authors.forename: Felix M
authors.initials: FM
authors.lastname: Gonzalez
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Dodson
authors.forename: William B
authors.initials: WB
authors.lastname: Morrison
authors.forename: Adam C
authors.initials: AC
authors.lastname: Zoga
mesh_terms: D000293:Adolescent; D017677:Age Distribution; D002968:Clavicle / Q000473:pathology*; D005260:Female; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D010014:Osteolysis / Q000473:pathology*; D015143:Philadelphia / Q000453:epidemiology; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D014891:Weight Lifting / Q000706:statistics & numerical data*; D055815:Young Adult