title: Distal clavicular osteolysis in adults: association with bench pressing intensity.
abstract: OBJECTIVE
  To investigate the association between distal clavicular osteolysis (DCO) and bench pressing intensity.
  
  
  METHODS
  From a retrospective review of MRI shoulder reports of individuals between 20 and 40 years of age, 262 male patients with DCO and 227 age-matched male patients without DCO were selected. All patients had completed a bench pressing questionnaire. The patients' bench pressing frequency (times per week), duration (years of bench pressing), bench pressing weight (maximum bench pressing weight with one repetition = 1RM) and the ratio of bench pressing weight to body weight were compared between both groups using Chi-square and Mann-Whitney tests.
  
  
  RESULTS
  The results showed that 56 % (146/262) of patients with DCO were high-intensity bench pressers (1RM more than 1.5 times the body weight) compared to 6 % (14/227) in patients without DCO. High-intensity bench pressing was a risk factor for DCO (OR = 19; 95 %CI = 11-35; p < 0.001). Low-intensity bench pressing (1RM less than 1.5 times the body weight) was not a risk factor for DCO (OR = 0.6; 95 % CI = 0.4-0.8). High frequency (>1×/week) and duration (>5 years) of bench pressing were risk factors. In bench pressers who suffered from DCO, the mean 1RM was 283 lbs (±SD 57) compared to 209 lbs (±SD 60) in bench pressers not affected by DCO (p < 0.001, Mann-Whitney).
  
  
  CONCLUSIONS
  High-intensity, but not low-intensity bench pressing is a risk factor for DCO.
authors.affiliation: Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, 132 South 10th Street, Philadelphia, PA, 19107, USA.
authors.forename: Mika T
authors.initials: MT
authors.lastname: Nevalainen
authors.affiliation: Division of Sports Medicine, Department of Orthopedic Surgery, Thomas Jefferson University Hospital, Rothman Institute, Sidney Kimmel Medical College at Thomas Jefferson University, 925 Chestnut St, 5th Floor, Philadelphia, PA, 19107, USA.
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ciccotti
authors.affiliation: Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, 132 South 10th Street, Philadelphia, PA, 19107, USA.
authors.forename: William B
authors.initials: WB
authors.lastname: Morrison
authors.affiliation: Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Sidney Kimmel Medical College at Thomas Jefferson University, 132 South 10th Street, Philadelphia, PA, 19107, USA.
authors.forename: Adam C
authors.initials: AC
authors.lastname: Zoga
authors.affiliation: Division of Musculoskeletal Imaging and Interventions, Department of Radiology, Thomas Jefferson University Hospital, Sidney Kimmel Medical College at 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
mesh_terms: D000328:Adult; D002968:Clavicle / Q000000981:diagnostic imaging / Q000502:physiology*; D006801:Humans; D008297:Male; D010014:Osteolysis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000503:physiopathology*; D010414:Pennsylvania / Q000453:epidemiology; D005082:Physical Exertion; D015995:Prevalence; D055070:Resistance Training / Q000379:methods / Q000706:statistics & numerical data*; D012307:Risk Factors; D014891:Weight Lifting / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: Acromioclavicular joint; Bench pressing; Clavicular resection; Distal clavicular osteolysis; MRI; Magnetic resonance imaging; Osteoarthritis