title: Effects of glenoid component version on humeral head displacement and joint reaction forces: an experimental study.
abstract: The purpose of this study was to determine whether changes in glenoid version are associated with humeral head displacement and changes in the joint reaction forces, as these might contribute to instability or loosening in total shoulder replacement. A total shoulder prosthesis was implanted in neutral version in 6 cadaveric shoulders. Glenoid version was then changed in steps of 4 degrees toward more anteversion and retroversion. An increase in anteversion resulted in anterior translation of the humeral head and in eccentric loading of the anterior part of the glenoid. Retroversion was associated with posterior displacement and posterior loading of the glenoid. A change in rotation of the humeral component did not compensate for altered version of the glenoid component. These results suggest that both instability and glenoid component loosening may be related to the version of the glenoid component. Therefore, assessment of loosening and instability justifies precise assessment of glenoid component version.
authors.affiliation: Department of Orthopaedics, University of Zurich, Balgrist Hospital, Zurich, Switzerland.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Nyffeler
authors.forename: Ralph
authors.initials: R
authors.lastname: Sheikh
authors.forename: Todd S
authors.initials: TS
authors.lastname: Atkinson
authors.forename: Hilaire A C
authors.initials: HA
authors.lastname: Jacob
authors.forename: Philippe
authors.initials: P
authors.lastname: Favre
authors.forename: Christian
authors.initials: C
authors.lastname: Gerber
mesh_terms: D019643:Arthroplasty, Replacement; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D006811:Humerus / Q000502:physiology* / Q000601:surgery; D007593:Joint Instability / Q000503:physiopathology*; D007595:Joint Prosthesis; D008954:Models, Biological; D011475:Prosthesis Failure; D012785:Shoulder Joint / Q000502:physiology* / Q000601:surgery