title: Patient-specific instrument guidance of glenoid component implantation reduces inclination variability in total and reverse shoulder arthroplasty.
abstract: BACKGROUND
  The aim of this study was to assess the influence of 3-dimensional (3D) preoperative planning and patient-specific instrument (PSI) guidance of glenoid component positioning on its inclination in total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA).
  
  
  METHODS
  Thirty-six shoulder arthroplasties (12 TSAs, 24 RSAs) were analyzed, of which 18 procedures (6 TSAs, 12 RSAs) were executed using preoperative 3D planning and patient-specific guides to position the central guide pin for glenoid component implantation. In 9 cases, the glenoid anatomy was severely distorted through wear or previous surgery. The inclination of the glenoid component was measured by 2 observers, using the angle between the glenoid baseplate and the floor of the supraspinatus fossa (angle β) on postoperative radiographs.
  
  
  RESULTS
  For TSA, the average angle β was 74 ± 9 in the PSI group and 86 ± 12 in the non-PSI group; for RSA, the average angle β was 83 ± 7 in the PSI group and 90 ± 17 in the non-PSI group. Extreme angles β, which represent extreme values of glenoid component inclination, are more likely to occur in the non-PSI group than in the PSI group (P < .001 for TSA; P = .02 for RSA).
  
  
  CONCLUSIONS
  The3D preoperative surgical planning and PSI guidance reduce variability in glenoid component inclination and avoid extreme inclination errors for TSA and RSA.
authors.affiliation: Department of Orthopedic Surgery, AZ Monica, Antwerp, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: Heylen
authors.affiliation: Department of Orthopedic Surgery, AZ Monica, Antwerp, Belgium; Department of Electrical Energy, Systems and Automation, Ghent University, Ghent, Belgium.
authors.forename: Annemieke
authors.initials: A
authors.lastname: Van Haver
authors.affiliation: Department of Orthopedic Surgery, AZ Monica, Antwerp, Belgium.
authors.forename: Kristien
authors.initials: K
authors.lastname: Vuylsteke
authors.affiliation: Department of Orthopedic Surgery, AZ Monica, Antwerp, Belgium.
authors.forename: Geert
authors.initials: G
authors.lastname: Declercq
authors.affiliation: Department of Orthopedic Surgery, AZ Monica, Antwerp, Belgium. Electronic address: olivier.verborgt@telenet.be.
authors.forename: Olivier
authors.initials: O
authors.lastname: Verborgt
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000295:instrumentation* / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D061165:Glenoid Cavity / Q000000981:diagnostic imaging* / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007430:Intraoperative Care / Q000295:instrumentation*; D008297:Male; D011300:Preoperative Care; D011859:Radiography; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000601:surgery*
keywords: Shoulder arthroplasty; glenoid component implantation; patient-specific targeting guides; standard guides