title: Does scapular morphology affect the integrity of the rotator cuff?
abstract: BACKGROUND
  Current evidence suggests that distinct scapular morphologies may predispose patients to a rotator cuff tear. The objective of this longitudinal study was to evaluate the relationship between symptomatic degenerative cuff tears and different radiographic acromial characteristics, including acromion shape, indices (acromial index [AI], critical shoulder angle [CSA]), and acromial spur.
  
  
  METHODS
  We divided 166 patients into 3 groups matched for age and sex: group 1, degenerative full-thickness tear; group 2, partial thickness bursal tear; and group 3, normal cuff. Patients were evaluated with standard radiographs and ultrasonography.
  
  
  RESULTS
  The presence of an acromial spur was strongly associated with a full-thickness cuff tear (odds ratio, 3.5; P = .001). AI and CSA revealed a statistically significant difference between means of group 1 (P = .006) and group 3 (P < .001). There was no statistically significant difference in means of AI between groups 1 and 2 (P = .695) and between groups 2 and 3, with respect to AI (P = .071) and CSA (P = .125). Receiver operating characteristic curve revealed a higher area for CSA (0.70) than for AI (0.61). Stepwise logistic regression rejected AI as a cuff tear predictor but confirmed CSA and a spur to be stronger predictors of a full-thickness cuff tear. There was no association between the Bigliani acromial type and rotator cuff tear (P = .06).
  
  
  CONCLUSIONS
  The presence of an acromion spur is strongly associated with full-thickness cuff tear. Higher AI and CSA are associated with a full-thickness tear but not with partial tears. The type of acromion is not related to cuff tear.
authors.affiliation: Department of Orthopaedics, Kasturba Medical College, Manipal, Karnataka, India. Electronic address: vivekortho@gmail.com.
authors.forename: Vivek
authors.initials: V
authors.lastname: Pandey
authors.affiliation: Department of Orthopaedics, Kasturba Medical College, Manipal, Karnataka, India.
authors.forename: Deepu
authors.initials: D
authors.lastname: Vijayan
authors.affiliation: Department of Orthopaedics, Kasturba Medical College, Manipal, Karnataka, India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Tapashetti
authors.affiliation: Department of Orthopaedics, Kasturba Medical College, Manipal, Karnataka, India.
authors.forename: Lipisha
authors.initials: L
authors.lastname: Agarwal
authors.affiliation: Community Medicine and Statistics, Kasturba Medical College, Manipal, Karnataka, India.
authors.forename: Asha
authors.initials: A
authors.lastname: Kamath
authors.affiliation: Department of Orthopaedics, Kasturba Medical College, Manipal, Karnataka, India.
authors.forename: Kiran
authors.initials: K
authors.lastname: Acharya
authors.affiliation: Department of Radiodiagnosis, Kasturba Medical College, Manipal, Karnataka, India.
authors.forename: Satish
authors.initials: S
authors.lastname: Maddukuri
authors.affiliation: Shoulder Unit, Lairesse Kliniek, Amsterdam, The Netherlands.
authors.forename: W Jaap
authors.initials: WJ
authors.lastname: Willems
mesh_terms: D000174:Acromion / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D054850:Osteophyte / Q000000981:diagnostic imaging* / Q000453:epidemiology; D012372:ROC Curve; D011859:Radiography; D017006:Rotator Cuff / Q000000981:diagnostic imaging; D000070636:Rotator Cuff Injuries; D012421:Rupture / Q000000981:diagnostic imaging / Q000453:epidemiology; D012785:Shoulder Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014463:Ultrasonography
keywords: Scapular morphology; acromion; acromion index; acromion shape; acromion spur; critical shoulder angle; degenerative tear; rotator cuff