title: Differences in glenohumeral joint morphology between patients with anterior shoulder instability and healthy, uninjured volunteers.
abstract: BACKGROUND
  Traumatic glenohumeral joint (GHJ) dislocations are common, resulting in significant shoulder disability and pain. Previous research indicates that bony morphology is associated with an increased risk of injury in other joints (eg, the knee), but the extent to which bony morphology is associated with traumatic GHJ dislocation is unknown. This study assessed GHJ morphology in patients with anterior GHJ instability and in a control population of healthy volunteers.
  
  
  METHODS
  Bilateral computed tomography scans were used to measure GHJ morphology in both shoulders of 11 patients with instability and 11 control subjects. Specific outcome measures included the glenoid radius of curvature (ROC) in the anterior/posterior (A/P) and superior/inferior (S/I) directions, humeral head ROC, A/P and S/I conformity index, and A/P and S/I stability angle.
  
  
  RESULTS
  Compared with the control subjects, the glenoid of the instability the injured shoulder in patients with instability was flatter (ie, higher ROC) in the A/P (P = .001) and S/I (P = .01) directions and this finding was also true for uninjured, contralateral shoulder (A/P: P = .01, S/I: P = .03). No differences in GHJ morphology were detected between the instability patients' injured and contralateral shoulders (P > .07). Similarly, no differences in GHJ morphology were detected between the control subjects' dominant and nondominant shoulders (P > .51).
  
  
  CONCLUSIONS
  There are significant differences in GHJ morphology between healthy control subjects and both shoulders (injured and uninjured, contralateral) of patients diagnosed with anterior instability after GHJ dislocation. These findings are important clinically because they suggest that glenoid morphology may influence the risk of GHJ dislocation.
authors.affiliation: Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA. Electronic address: cpeltz1@hfhs.org.
authors.forename: Cathryn D
authors.initials: CD
authors.lastname: Peltz
authors.affiliation: Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Roger
authors.initials: R
authors.lastname: Zauel
authors.affiliation: Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Nicole
authors.initials: N
authors.lastname: Ramo
authors.affiliation: Department of Orthopaedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Nima
authors.initials: N
authors.lastname: Mehran
authors.affiliation: Department of Orthopaedic Surgery, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Vasilios
authors.initials: V
authors.lastname: Moutzouros
authors.affiliation: Bone and Joint Center, Henry Ford Hospital, Detroit, MI, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Bey
mesh_terms: D016022:Case-Control Studies; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional; D007593:Joint Instability / Q000000981:diagnostic imaging* / Q000503:physiopathology; D008297:Male; D012189:Retrospective Studies; D012783:Shoulder Dislocation / Q000000981:diagnostic imaging / Q000503:physiopathology; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000502:physiology; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Glenohumeral instability; anterior instability; bony morphology; glenoid morphology; humeral head morphology; radius of curvature; traumatic instability