title: Biometrical analysis of the shoulder joint regarding glenoid implant dimensions for arthroplasty.
abstract: OBJECTIVE
  Reduced bone stock and difficult intraoperative orientation are challenges in glenoid replacement surgery. New implant designs and methods for fixation, such as locking screws, extra-long central pegs and/or central compression screws are targeting these issues. The objective of this study is the analysis of the glenoid dimension regarding maximum central peg diameter and peg length (PL), and maximum screw length (SL) for glenoid fixation.
  
  
  METHODS
  Retrospective analysis of magnetic resonance imaging (n = 50) scans. Measurement of the maximum inferior glenoid diameter (GD), SL, maximum length of a 9.9, 10 and 11.4 mm central peg (PL) in the transverse plane; glenoid version (GV), humeral head diameter (HHD). Two independent measurements.
  
  
  RESULTS
  Mean age: 49.0 ± 15.7 years (17-80) (n = 20 female, 49.6 ± 16.0; n = 30 male, 48.6 ± 15.7). Mean values of measurement were GD: 28.9 ± 3.7 mm (21-39); SL: 34.1 ± 4.9 mm (26-44); PL 9.9 mm: 19.4 ± 4.3 mm (9-30); PL 10 mm: 19.0 ± 4.4 mm (8-30); PL 11.4 mm: 16.5 ± 4.1 mm (7-26) with significant gender differences (p = 0.001; p = 0.022; p = 0.001); GV: -0.6° ± 4.9° (-10 to 11); HHD: 50.0 mm ± 4.9 (41-61). There was good correlation between PL and SL (r = 0.32, p = 0.024) and for GD and PL (r = 0.61, p = 0.001; r = 0.57, p = 0.001; r = 0.96, p = 0.001). The ratio of HHD and GD was very constant with 0.6 ± 0.07.
  
  
  CONCLUSIONS
  These data indicate the high interindividual variability of glenoid morphology including significant gender-related differences. The good correlation between humeral head size and GD and maximum central PL can be helpful for cases with reduced bone stock in decision-making about implant size and bone grafting.
authors.affiliation: Department of Orthopedics, Medical Faculty, Heinrich-Heine-University Düsseldorf, Moorenstrasse 5, 40255, Düsseldorf, Germany, j-kircher@web.de.
authors.forename: Jörn
authors.initials: J
authors.lastname: Kircher
authors.forename: Bernd
authors.initials: B
authors.lastname: Bittersohl
authors.forename: Christoph
authors.initials: C
authors.lastname: Zilkens
authors.forename: Achim
authors.initials: A
authors.lastname: Hedtmann
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Krauspe
mesh_terms: D019643:Arthroplasty, Replacement; D001699:Biometry / Q000379:methods; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012785:Shoulder Joint / Q000033:anatomy & histology* / Q000601:surgery