title: Glenoid version and inclination are risk factors for anterior shoulder dislocation.
abstract: OBJECTIVE
  Although the contribution of the capsuloligamentous structures and dynamic muscle balance to shoulder stability has been well documented, the role of the osseous anatomy of the glenoid has not been thoroughly evaluated. This study investigated glenoid version and inclination in patients with a documented anterior shoulder dislocation and compared it with a control group. We hypothesized that patients with a prior anterior dislocation would have more anterior version and increased inferior inclination of the glenoid.
  
  
  METHODS
  Patients aged younger than 40 years who underwent arthroscopic shoulder stabilization (study group) were compared with patients (control group) who had previously undergone magnetic resonance imaging (MRI) for a different shoulder condition. Version was measured on axial images, and inclination was measured on coronal images of a T2-weighted spin-echo scan. The MRIs of 128 study group patients (mean age, 24.5 ± 8.6 years) with a confirmed traumatic anterior shoulder dislocation were compared with the MRIs of 130 control group patients (mean age, 30.9 ± 7 years).
  
  
  RESULTS
  The mean version in the study group was -1.7° ± 4.5° (retroversion); the mean inclination was 1.6° ± 5.9° (inferior). The mean version in the control group was -5.8° ± 4.6° (retroversion); the mean inclination was -4.0° ± 6.8° (superior). The between-group differences were significant for version (P = .00001) and inclination (P = .00001).
  
  
  CONCLUSIONS
  The results of this study strongly suggest that glenoid version and inclination are significantly increased in patients with established anterior shoulder instability compared with a matched control group.
authors.affiliation: Department of Orthopaedic Surgery, Clinical Medical School, University of Queensland, Brisbane, QLD, Australia; Musculoskeletal Research Unit, Central Queensland University, Rockhampton, QLD, Australia. Electronic address: ehohmann@optusnet.com.au.
authors.forename: Erik
authors.initials: E
authors.lastname: Hohmann
authors.affiliation: Department of Orthopaedic Surgery, Royal Brisbane Hospital, Herston, QLD, Australia; Department of Surgery, School of Medicine, University of Queensland, Brisbane, QLD, Australia.
authors.forename: Kevin
authors.initials: K
authors.lastname: Tetsworth
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000379:methods*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D012307:Risk Factors; D012783:Shoulder Dislocation / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D012785:Shoulder Joint / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D055815:Young Adult
keywords: Anterior shoulder dislocation; glenohumeral subluxation; glenoid inclination; glenoid version; risk factor; shoulder injury