title: Outcomes of arthroscopic anterior shoulder instability in the beach chair versus lateral decubitus position: a systematic review and meta-regression analysis.
abstract: OBJECTIVE
  This study aimed to systematically review the clinical outcomes and recurrence rates after arthroscopic anterior shoulder stabilization in the beach chair (BC) and lateral decubitus (LD) positions.
  
  
  METHODS
  The authors performed a systematic review of multiple medical databases using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All English-language literature from 1990 to 2013 reporting clinical outcomes after arthroscopic anterior shoulder stabilization with suture anchors or tacks with a minimum 2-year follow-up period were reviewed by 2 independent reviewers. Data on recurrent instability rate, return to activity/sport, range of motion, and subjective outcome measures were collected. Study methodological quality was evaluated with the Modified Coleman Methodology Score (MCMS) and the Quality Appraisal Tool (QAT). To quantify the structured review of observational data, meta-analytic statistical methods were used.
  
  
  RESULTS
  Sixty-four studies (38 BC position, 26 LD position) met inclusion criteria. A total of 3,668 shoulders were included, with 2,211 of patients in the BC position (average age, 26.7 ± 3.8 years; 84.5% male sex) and 1,457 patients in the LD position (average age, 26.0 ± 3.0 years; 82.7% male sex). The average follow-up was 49.8 ± 29.5 months in the BC group compared with 38.7 ± 23.3 months in the LD group. Average overall recurrent instability rates were 14.65 ± 8.4% in the BC group (range, 0% to 38%) compared with 8.5% ± 7.1% in the LD group (range, 0% to 30%; P = .002). The average postoperative loss in external rotation motion (in abduction) was reported in 19 studies in the BC group and in13 studies in the LD group, with an average loss of 2.4° ± 1.0° and 3.6° ± 2.6° in each group, respectively (P > .05).
  
  
  CONCLUSIONS
  Excellent clinical outcomes with low recurrence rates can be obtained after arthroscopic anterior shoulder stabilization in either the BC or the LD position; however, lower recurrence rates are noted in the LD position. Additional long-term randomized clinical trials comparing these positions are needed to better understand the potential advantages and disadvantages of each position.
  
  
  METHODS
  Level IV, systematic review of studies with Level I through Level IV evidence.
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.. Electronic address: rmfrank3@gmail.com.
authors.forename: Rachel M
authors.initials: RM
authors.lastname: Frank
authors.affiliation: Department of Orthopedics, Catholic University, Rome, Italy.
authors.forename: Maristella F
authors.initials: MF
authors.lastname: Saccomanno
authors.affiliation: Naval Medical Center San Diego, San Diego, California, U.S.A.
authors.forename: Lucas S
authors.initials: LS
authors.lastname: McDonald
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Mario
authors.initials: M
authors.lastname: Moric
authors.affiliation: Division of Sports Medicine, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, Illinois, U.S.A.
authors.forename: Anthony A
authors.initials: AA
authors.lastname: Romeo
authors.affiliation: Division of Sports Medicine and Surgery, Department of Orthopaedic Surgery, Massachusetts General Hospital, Boston, Massachusetts, U.S.A.
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Provencher
mesh_terms: D001182:Arthroscopy; D006801:Humans; D007593:Joint Instability / Q000601:surgery*; D056888:Patient Positioning; D012783:Shoulder Dislocation / Q000601:surgery; D012785:Shoulder Joint / Q000601:surgery*; D016896:Treatment Outcome