title: Impingement contributes to backside wear and screw-metallic shell fretting in modular acetabular cups.
abstract: Eighty-six polyethylene liners and 56 metallic shells of acetabular components were evaluated by visual and stereomicroscopic examination for impingement, backside polyethylene wear, creep, and fretting at the screw-metallic shell interface using a subjective scoring system. Medical records and radiological data were available in 65 and 46 patients, respectively. Impingement was found in 62 components (75%). Backside polyethylene wear and screw-metallic shell corrosion and fretting were significantly correlated (P < .001) with impingement. Polyethylene creep was significantly correlated to backside wear and tended to be higher for the cups that had impingement (P = .06). No correlation was found between backside polyethylene wear and implant design or cup position. Our results suggest that impingement in a modular acetabular component correlated with increased backside wear and screw-metallic shell corrosion and fretting.
authors.affiliation: Laboratory for Biomedical Mechanics and Materials, Hospital for Special Surgery, New York, New York, USA.
authors.forename: Mordechai
authors.initials: M
authors.lastname: Kligman
authors.forename: Bridgitte D
authors.initials: BD
authors.lastname: Furman
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Padgett
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Wright
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D001696:Biomechanical Phenomena; D001863:Bone Screws; D003343:Corrosion; D019544:Equipment Failure Analysis; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011095:Polyethylenes; D011474:Prosthesis Design; D011475:Prosthesis Failure; D018709:Statistics, Nonparametric
chemical_list: D011095:Polyethylenes