title: Primary stability of inferior tilt fixation of the glenoid component in reverse total shoulder arthroplasty: A finite element study.
abstract: Glenoid component fixation with inferior tilt has been suggested as one of the surgical methods to decrease scapular notching and improve stability, but its clinically beneficial effect remains a concern. We evaluated the influence of inferior tilt fixation of the glenoid component on primary stability in reverse total shoulder arthroplasty by finite element analysis. Finite element models were constructed from cadaveric scapulae of females over the age of 60 years and glenoid components from reverse total shoulder arthroplasty. The relative micromotion at the bone-glenoid component interface, distribution of bone stress under the glenoid component and around the screws, contact area between the bone and screws, and cut surface area of the cancellous bone exposed after glenoid reaming were analyzed and compared between a neutral and 10° inferior tilt fixation of the glenoid component. The 10° inferior tilt fixation demonstrated greater relative micromotion and higher bone stress than the neutral tilt fixation. Eccentric reaming, which is done to produce the inferior tilt fixation of the glenoid component, increased glenoid cancellous bone exposure and decreased bone-screws contact area. Inferior tilt fixation of the glenoid component may adversely affect primary stability and longevity after reverse total shoulder arthroplasty. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1061-1068, 2016.
authors.affiliation: Department of Mechanical Engineering, Korea University, Seoul, South Korea.
authors.forename: Soo-Won
authors.initials: SW
authors.lastname: Chae
authors.affiliation: Department of Mechanical Engineering, Korea University, Seoul, South Korea.
authors.forename: Haea
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Korea University, Seoul, South Korea.
authors.forename: Soo Min
authors.initials: SM
authors.lastname: Kim
authors.affiliation: Department of Biostatistics, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Juneyoung
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Anatomy, College of Medicine, Chung-Ang University, Seoul, South Korea.
authors.forename: Seung-Ho
authors.initials: SH
authors.lastname: Han
authors.affiliation: Department of Orthopaedic Surgery, Hallym University Kangnam Sacred Heart Hospital, Seoul, South Korea.
authors.forename: Soung-Yon
authors.initials: SY
authors.lastname: Kim
mesh_terms: D000368:Aged; D000072228:Arthroplasty, Replacement, Shoulder / Q000295:instrumentation / Q000379:methods*; D001863:Bone Screws; D020342:Finite Element Analysis; D006801:Humans; D013314:Stress, Mechanical
keywords: finite element analysis; glenoid component; inferior tilt; primary stability; reverse total shoulder arthroplasty