title: Cracking and impingement in ultra-high-molecular-weight polyethylene acetabular liners.
abstract: The purpose of this study was to determine the prevalence of crack formation in conventional ultra-high-molecular-weight polyethylene cups and its association with rim impingement, oxidation, and time in situ. One hundred twenty acetabular cups were retrieved during revision total hip arthroplasty. In 40% (48/120) of the retrieved specimens, multiple subsurface cracks of several millimeters in length were revealed by transillumination. In 5 specimens, full thickness cracks led to fragmentation of the liner before revision. Thirty-eight (32%) liners had regions of moderate to severe impingement damage to the rim; cracks were initiated at the site of impingement in all but 1 liner (P < .0001). Cracks commonly occur in conventional ultra-high-molecular-weight polyethylene liners, often after neck impingement and almost always in association with oxidation of the polymer.
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Birman
authors.forename: Philip C
authors.initials: PC
authors.lastname: Noble
authors.forename: Michael A
authors.initials: MA
authors.lastname: Conditt
authors.forename: Steve
authors.initials: S
authors.lastname: Li
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Mathis
mesh_terms: D000077:Acetabulum; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D006622:Hip Prosthesis; D006801:Humans; D008875:Middle Aged; D011095:Polyethylenes; D011474:Prosthesis Design; D011475:Prosthesis Failure
chemical_list: D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene