title: Wear of a sequentially annealed polyethylene acetabular liner.
abstract: OBJECTIVE
  We previously reported on a randomized controlled trial (RCT) that examined the effect of adding tobramycin to bone cement after femoral stem migration. The present study examined femoral head penetration into both conventional and highly crosslinked polyethylene acetabular liners in the same group of RCT patients, with a minimum of 5 years of postoperative follow-up.
  
  
  METHODS
  Linear penetration of the femoral head into an X3 (Stryker) crosslinked polyethylene (XLPE) liner was measured in 18 patients (19 hips) using radiostereometric analysis (RSA). Femoral head penetration was also measured in 6 patients (6 hips) with a conventional polyethylene liner (CPE), which served as a control group.
  
  
  RESULTS
  The median proximal femoral head penetration in the XLPE group after 5.5 years was 0.025 mm with a steady-state penetration rate of 0.001 mm/year between year 1 and year 5. The CPE liner showed a median proximal head penetration of 0.274 mm after 7.2 years, at a rate of 0.037 mm/year.
  
  
  CONCLUSIONS
  The Trident X3 sequentially annealed XLPE liner shows excellent in vivo wear resistance compared to non-crosslinked CPE liners at medium-term implantation. The rate of linear head penetration in the XLPE liners after > 5 years of follow-up was 0.001 mm/year, which is in close agreement with the results of previous studies.
authors.affiliation: Orthopaedic Innovation Centre.
authors.forename: Trevor C
authors.initials: TC
authors.lastname: Gascoyne
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Petrak
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Turgeon
authors.forename: Eric R
authors.initials: ER
authors.lastname: Bohm
mesh_terms: D000077:Acetabulum / Q000473:pathology; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000379:methods; D001843:Bone Cements / Q000009:adverse effects / Q000627:therapeutic use*; D005260:Female; D005270:Femur Head / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis
chemical_list: D001843:Bone Cements; D020959:Polyethylene