title: Thirteen-Year Evaluation of Highly Cross-Linked Polyethylene Articulating With Either 28-mm or 36-mm Femoral Heads Using Radiostereometric Analysis and Computerized Tomography.
abstract: The objective of this 13-year prospective evaluation of highly cross-linked ultra high molecular weight polyethylene (HXLPE) was to (1) assess the long-term wear of HXLPE articulating with 2 femoral head sizes using radiostereometric analysis (RSA) and to (2) determine if osteolysis is a concern with this material through the use of plain radiographs and computerized tomography (CT).
  
  
  
  All patients received a Longevity HXLPE liner with tantalum beads and either a 28-mm or 36-mm femoral head. Twelve patients (6 in each head size group) agreed to return for 13-year RSA, plain radiograph, and CT follow-up. The 1-year and 13-year plain radiographs as well as the CT scans were analyzed for the presence of osteolysis.
  
  
  
  The 13-year mean ± standard error steady-state wear was 0.05 ± 0.02 mm with no significant increase over time or between the 2 head size groups. Two patients' CT scans showed radiolucent regions in the acetabulum of 4.51 cm(3) and 11.25 cm(3), respectively. In one patient, this area corresponded to a partially healed degenerative cyst treated with autograft during surgery. The second patient had an acetabular protrusio treated with autograft, and the CT scan revealed areas of remodeling of this graft. One patient's 13-year plain radiographs showed evidence of cup loosening and linear radiolucencies in zones 2 and 3.
  
  
  
  There was no evidence of significant wear over time using RSA. The CT scans did not show evidence of osteolysis due to wear particles. These results suggest that this material has reduced wear compared to conventional polyethylene, irrespective of head size.
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Audrey K
authors.initials: AK
authors.lastname: Nebergall
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Meridith E
authors.initials: ME
authors.lastname: Greene
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Harry
authors.initials: H
authors.lastname: Rubash
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Henrik
authors.initials: H
authors.lastname: Malchau
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts; Department of Orthopaedics, Copenhagen University Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Anders
authors.initials: A
authors.lastname: Troelsen
authors.affiliation: Department of Orthopaedics, Harris Orthopaedic Laboratory, Massachusetts General Hospital, Boston, Massachusetts; Department of Orthopaedics, Institute of Clinical Sciences at Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Rolfson
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001847:Bone Diseases / Q000601:surgery; D002357:Cartilage Diseases / Q000601:surgery; D005260:Female; D005270:Femur Head / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis; D020959:Polyethylene / Q000737:chemistry*; D011095:Polyethylenes / Q000737:chemistry; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis; D013635:Tantalum; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D011095:Polyethylenes; C111601:ultra-high molecular weight polyethylene; D013635:Tantalum; D020959:Polyethylene
keywords: computerized tomography; highly cross-linked polyethylene; large femoral head; osteolysis; radiostereometic analysis; total hip arthroplasty