title: Mean Glenoid Defect Size and Location Associated With Anterior Shoulder Instability: A Systematic Review.
abstract: BACKGROUND
  There is a strong correlation between glenoid defect size and recurrent anterior shoulder instability. A better understanding of glenoid defects could lead to improved treatments and outcomes.
  
  
  OBJECTIVE
  To (1) determine the rate of reporting numeric measurements for glenoid defect size, (2) determine the consistency of glenoid defect size and location reported within the literature, (3) define the typical size and location of glenoid defects, and (4) determine whether a correlation exists between defect size and treatment outcome.
  
  
  METHODS
  Systematic review; Level of evidence, 4.
  
  
  METHODS
  PubMed, Ovid, and Cochrane databases were searched for clinical studies measuring glenoid defect size or location. We excluded studies with defect size requirements or pathology other than anterior instability and studies that included patients with known prior surgery. Our search produced 83 studies; 38 studies provided numeric measurements for glenoid defect size and 2 for defect location.
  
  
  RESULTS
  From 1981 to 2000, a total of 5.6% (1 of 18) of the studies reported numeric measurements for glenoid defect size; from 2001 to 2014, the rate of reporting glenoid defects increased to 58.7% (37 of 63). Fourteen studies (n = 1363 shoulders) reported defect size ranges for percentage loss of glenoid width, and 9 studies (n = 570 shoulders) reported defect size ranges for percentage loss of glenoid surface area. According to 2 studies, the mean glenoid defect orientation was pointing toward the 3:01 and 3:20 positions on the glenoid clock face.
  
  
  CONCLUSIONS
  Since 2001, the rate of reporting numeric measurements for glenoid defect size was only 58.7%. Among studies reporting the percentage loss of glenoid width, 23.6% of shoulders had a defect between 10% and 25%, and among studies reporting the percentage loss of glenoid surface area, 44.7% of shoulders had a defect between 5% and 20%. There is significant variability in the way glenoid bone loss is measured, calculated, and reported.
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Lionel J
authors.initials: LJ
authors.lastname: Gottschalk
authors.affiliation: Section of Orthopaedic Surgery, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Bois
authors.affiliation: School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Shelby
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio, USA.; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Miniaci
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio, USA.; Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA.
authors.forename: Morgan H
authors.initials: MH
authors.lastname: Jones
keywords: Bankart; anterior shoulder instability; bony Bankart; glenoid bone defect; glenoid bone loss; glenoid defect