title: Management of intraoperative posterior decentering in shoulder arthroplasty using anteriorly eccentric humeral head components.
abstract: BACKGROUND
  Posterior humeral decentering presents a challenge in glenohumeral arthroplasty. Soft tissue releases and osteophyte resection can lead to intraoperative decentering not evident preoperatively. Inferior outcomes result if decentering is not addressed as a part of the arthroplasty. When there is >50% posterior subluxation of the humeral head on passive elevation of the arm at surgery, we have used an anteriorly eccentric humeral head component to improve centering of the humeral articular surface on the glenoid.
  
  
  METHODS
  We reviewed the 2-year outcomes for 33 shoulder arthroplasties in which anteriorly eccentric humeral heads were used to manage posterior decentering identified at surgery. Rotator interval plication was performed in 16 cases as an adjunctive stabilizing procedure. Shoulders were evaluated preoperatively and postoperatively with the Simple Shoulder Test (SST). Radiographic centering was characterized before surgery and at follow-up on standardized axillary radiographs with the arm held in a position of functional elevation.
  
  
  RESULTS
  With the anteriorly eccentric head component, preoperative radiographic humeral decentering was reduced from 10.4% ± 7.9% to 0.9% ± 2.3% postoperatively (P < .001). SST scores improved from 4.8 ± 2.3 to 10.0 ± 2.3 (P < .001). Preoperative posterior humeral head decentering did not correlate with preoperative glenoid version. Glenoid retroversion was 19.8° ± 8.9° preoperatively and 15.5° ± 7.5° postoperatively.
  
  
  CONCLUSIONS
  Posterior decentering identified at surgery when standard trial components are in place can be addressed by replacing the anatomic humeral head with an anteriorly eccentric humeral head component.
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Jason E
authors.initials: JE
authors.lastname: Hsu
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Albert O
authors.initials: AO
authors.lastname: Gee
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Lucas
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Jeremy S
authors.initials: JS
authors.lastname: Somerson
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Winston J
authors.initials: WJ
authors.lastname: Warme
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA. Electronic address: matsen@uw.edu.
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Matsen
mesh_terms: D000072228:Arthroplasty, Replacement, Shoulder / Q000379:methods*; D005260:Female; D006801:Humans; D058430:Humeral Head / Q000000981:diagnostic imaging / Q000601:surgery*; D007431:Intraoperative Complications / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D000072227:Shoulder Prosthesis
keywords: Eccentric humeral head; functional decentering; posterior decentering; ream and run; rotator interval plication; total shoulder arthroplasty