title: Eight-year wear analysis in Longevity highly cross-linked polyethylene liners comparing 26- and 32-mm heads.
abstract: BACKGROUND
  Although wear reduction of highly cross-linked polyethylene has been demonstrated to be independent of femoral head diameter in some simulation studies, the clinical effects of femoral head diameter on wear of highly cross-linked polyethylene sockets remain unclear. We compared the in vivo wear of Longevity highly cross-linked polyethylene liners at 8-year follow-up using 26- or 32-mm cobalt-chromium heads.
  
  
  METHODS
  A retrospective cohort study was performed on 90 cementless total hip arthroplasties (THAs) using Longevity highly cross-linked polyethylene liners combined with 26- (45 THAs) or 32-mm (45 THAs) cobalt-chromium heads. Annual radiographs were analyzed using PolyWare computer-assisted methods and linear and volumetric total head penetration rates and linear and volumetric steady-state wear rates were compared.
  
  
  RESULTS
  The two groups showed similar background data, and no significant differences were identified between groups in total head penetration rate or steady-state wear rate. Steady-state wear rates were negligible. Osteolysis was not observed in any hips in either group.
  
  
  CONCLUSIONS
  At the 8-year follow-up, wear of the Longevity was the same irrespective of the use 26- or 32-mm heads.
authors.affiliation: Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakahara
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nakamura
authors.forename: Masaki
authors.initials: M
authors.lastname: Takao
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
authors.forename: Takashi
authors.initials: T
authors.lastname: Nishii
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D020959:Polyethylene