title: Shoulder impingement: relationship of clinical symptoms and imaging criteria.
abstract: OBJECTIVE
  To establish, in patients with subacromial impingement syndrome, (1) the relationship between pain and shoulder function, as determined by the Constant score, and morphological findings, as determined by radiographs and magnetic resonance imaging (MRI) and (2) the relationship between acromial shape and minimum acromiohumeral distance (AHD).
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Tertiary care center.
  
  
  METHODS
  Forty-seven patients (33 males and 14 females; mean age, 51.7 years) with unilateral subacromial impingement syndrome who had failed to respond to conservative therapy for at least 6 months.
  
  
  METHODS
  The Constant score was determined preoperatively; acromial shape (type I, flat; type II, curved; and type III, hooked) was evaluated on preoperative outlet view radiographs and oblique sagittal T1-weighted MRIs; AHD was evaluated on preoperative anteroposterior radiographs and oblique coronal T1-weighted MRIs.
  
  
  METHODS
  Correlation coefficients and the simple kappa statistic were calculated. Student t test and mean differences with 95% confidence limits were reported for group comparisons.
  
  
  RESULTS
  The Constant score was fairly correlated with AHD (r = 0.39, P < 0.01) but not with acromial shape. Patients with an AHD < or =7 mm on MRI scored significantly lower than those with an AHD >7 (mean difference, 18.5; P < 0.01). Acromial shape and AHD were not correlated, neither on radiographs nor on MRI.
  
  
  CONCLUSIONS
  AHD seems to better reflect the clinical status of patients with subacromial impingement, but without rotator cuff tears, than acromial shape. Acromial shape is not a good descriptor of subacromial space narrowing.
authors.affiliation: Department of Radiology, Medical University of Vienna, Vienna, Austria. marius.mayerhoefer@meduniwien.ac.at
authors.forename: Marius E
authors.initials: ME
authors.lastname: Mayerhoefer
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Breitenseher
authors.forename: Christian
authors.initials: C
authors.lastname: Wurnig
authors.forename: Andreas
authors.initials: A
authors.lastname: Roposch
mesh_terms: D000174:Acromion / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000175:diagnosis / Q000209:etiology; D010147:Pain Measurement; D011859:Radiography; D016059:Range of Motion, Articular; D012720:Severity of Illness Index; D019534:Shoulder Impingement Syndrome / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging