title: Failure of the glenoid component in anatomic total shoulder arthroplasty: a systematic review of the English-language literature between 2006 and 2012.
abstract: BACKGROUND
  Although glenoid component failure is one of the most common complications of anatomic total shoulder arthroplasty, substantial evidence from the recent published literature is lacking regarding the temporal trend in the rate of this complication and the risk factors for its occurrence.
  
  
  METHODS
  We conducted a systematic review and identified twenty-seven articles presenting data on glenoid component failure rates that met the inclusion criteria. These articles represented data from 3853 total shoulder arthroplasties performed from 1976 to 2007.
  
  
  RESULTS
  Asymptomatic radiolucent lines occurred at a rate of 7.3% per year after the primary shoulder replacement. Symptomatic glenoid loosening occurred at 1.2% per year, and surgical revision occurred at 0.8% per year. There was no significant evidence that the rate of symptomatic loosening has diminished over time. Keeled components had greater rates of asymptomatic radiolucent lines compared with pegged components in side-by-side comparison studies. However, as a result of wide variability in outcomes reporting, only sex, Walch class, and diagnosis were significantly associated with the risk of glenoid component failure in the overall analysis.
  
  
  CONCLUSIONS
  This is the first systematic review of the published evidence on glenoid component failure. Although the authors of individual articles proposed various risk factors for glenoid component failure, many of these relationships were not significant in the present study. A consistent methodological approach to future investigations is likely to improve the quality of the evidence on which patients, techniques, and prostheses are selected for total shoulder arthroplasty.
authors.affiliation: Department of Orthopedics and Sports Medicine, University of Washington Medical Center, Box 356500, 1959 N.E. Pacific Street, Seattle, WA 98195. E-mail address for A. Papadonikolakis: apapadon@u.washington.edu. E-mail address for F.A. Matsen III: matsen@u.washington.edu.
authors.forename: Anastasios
authors.initials: A
authors.lastname: Papadonikolakis
authors.affiliation: The Mountain-Whisper-Light Statistics, 1827 23rd Avenue East, Seattle, WA 98112. E-mail address: moni@mwlight.com.
authors.forename: Moni Blazej
authors.initials: MB
authors.lastname: Neradilek
authors.affiliation: Department of Orthopedics and Sports Medicine, University of Washington Medical Center, Box 356500, 1959 N.E. Pacific Street, Seattle, WA 98195. E-mail address for A. Papadonikolakis: apapadon@u.washington.edu. E-mail address for F.A. Matsen III: matsen@u.washington.edu.
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Matsen
mesh_terms: D019643:Arthroplasty, Replacement; D006801:Humans; D010003:Osteoarthritis / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012785:Shoulder Joint / Q000601:surgery*; D016896:Treatment Outcome