title: Interface micromotion of uncemented femoral components from postmortem retrieved total hip replacements.
abstract: Axial torsional loads representative of gait and stair climbing conditions were applied to transverse sections of 8 uncemented postmortem retrievals and a high-resolution imaging system with digital image correlation was used to measure local micromotion along the bone-implant interface. For 7 components that were radiographically stable, there was limited micromotion for gait loading (1.42 ± 1.33 μm) that increased significantly (P = .0032) for stair climb loading (7.32 ± 9.96 μm). A radiographically loose component had motions on the order of 2.3 mm with gait loading. There was a strong inverse relationship between the amount of bone-implant contact (contact fraction) (P = .001) and micromotion. The uncemented components had greater contact fraction (41.8% ± 14.4% vs 11.5% ± 10.2%, P = .0033) and less median micromotion (0.81 ± 0.79 μm vs 28.8 ± 51.1 μm) compared to a previously reported study of cemented retrievals.
authors: SUNY Upstate Medical University, Syracuse, New York, USA.
authors: Kenneth A
authors: KA
authors: Mann
authors: Mark A
authors: MA
authors: Miller
authors: Peter A
authors: PA
authors: Costa
authors: Amos
authors: A
authors: Race
authors: Timothy H
authors: TH
authors: Izant
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D001344:Autopsy; D001696:Biomechanical Phenomena; D020878:Device Removal; D005269:Femur / Q000473:pathology / Q000601:surgery*; D005684:Gait; D006622:Hip Prosthesis; D006801:Humans; D008954:Models, Biological; D009038:Motion; D011474:Prosthesis Design; D012044:Regression Analysis; D016474:Weight-Bearing