title: Shell design and reaming technique affect deformation in mobile-bearing total hip arthroplasty acetabular components.
abstract: Press-fit acetabular components are susceptible to rim deformation. The inherent variability within acetabular reaming techniques may generate increased press-fit and, subsequently, additional component deformation. The purpose of this study was to analyze the insertion and deformation characteristics of acetabular components designed for dual-mobility systems based on component design, size, and reaming technique. Shell deformation was quantified in a validated worst-case scenario foam pinch model. Thin-walled, one-piece, and modular dual-mobility shells of varying size were implanted in under- and over-reamed cavities with insertion force measured and shell deformation assessed using digital image correlation. Increased shell size resulted in larger rim deformation in one-piece components, with a reduction in press-fit by 1 mm resulting in up to 48% reduction in insertion forces and between 23% and 51% reduction in shell deformation. Lower insertion forces and deformations were observed in modular components. Variability in acetabular reaming plays a significant role in the ease of implantation and component deformation in total hip arthroplasty. Modular components are less susceptible to deformation than thin-walled monoblock shells. Care should be taken to avoid excessive under-reaming, particularly in the scenario of large shell size and high-density patient bone stock.
authors.affiliation: 1 JRSI Foundation, Inc., Mooresville, IN, USA.
authors.forename: Scott R
authors.initials: SR
authors.lastname: Small
authors.affiliation: 1 JRSI Foundation, Inc., Mooresville, IN, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Meding
authors.affiliation: 2 Department of Biology & Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, USA.
authors.forename: Jordan W
authors.initials: JW
authors.lastname: Oja
authors.affiliation: 2 Department of Biology & Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, USA.
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Lakstins
authors.affiliation: 2 Department of Biology & Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, USA.
authors.forename: Danielle J
authors.initials: DJ
authors.lastname: Gehron
authors.affiliation: 2 Department of Biology & Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, USA.
authors.forename: Renee D
authors.initials: RD
authors.lastname: Rogge
authors.affiliation: 2 Department of Biology & Biomedical Engineering, Rose-Hulman Institute of Technology, Terre Haute, IN, USA.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Buckley
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D055595:Mechanical Phenomena; D011474:Prosthesis Design
keywords: Total hip arthroplasty; deformation; digital image correlation; modular; reaming