title: Effect of cementless acetabular cup geometry on strain distribution and press-fit stability.
abstract: Use of cementless acetabular cups, which are slightly larger than the reamed acetabulum, can provide press-fit stability without screws; however, the ideal cup geometry to maximize stability is not clear. Acetabular strain distribution, deformation, and implant stability were studied using an axisymmetric finite-element model, and mechanical stability was assessed by testing lever-out and extraction forces required to displace different cup geometries from foam bones. The implants tested included four nonhemispheric cup geometries and 1- and 2-mm oversized hemispheric geometries. A nonhemispheric cup that provides a gradual transition from a hemisphere at the dome to a larger peripheral dimension appears to maximize peripheral strains and implant stability without increasing overall acetabular deformation as much as a larger oversized hemispheric cup.
authors.affiliation: Mary Imogene Bassett Hospital, Cooperstown, New York 13326, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Ries
authors.forename: M
authors.initials: M
authors.lastname: Harbaugh
authors.forename: J
authors.initials: J
authors.lastname: Shea
authors.forename: R
authors.initials: R
authors.lastname: Lambert
mesh_terms: D000077:Acetabulum; D001696:Biomechanical Phenomena; D006622:Hip Prosthesis; D006801:Humans; D011474:Prosthesis Design