title: Wear Rates of Larger-Diameter Cross-Linked Polyethylene at 5 to 13 Years: Does Liner Thickness or Component Position Matter?
abstract: Cross-linked polyethylene (XLPE) has demonstrated significantly reduced wear and osteolysis into the second decade for total hip arthroplasty. There is a relative paucity of data with ≥36-mm bearings. Issues include potential effects of reduced liner thickness and component position on wear, osteolysis, and mechanical failure of the bearing.
  
  
  
  Radiographs of 48 primary total hip arthroplasties with ≥36-mm modular XLPE bearings were analyzed at a minimum 5 years postoperative on serial radiographs using a validated, edge-detection-based algorithm. Subgroups were examined to assess the effect of bearing diameter, liner thickness, acetabular abduction angle, and acetabular anteversion on XLPE wear.
  
  
  
  There was no significant difference in volumetric wear when subgroups were stratified by component factors: liner thickness (<6.5 mm vs ≥6.5 mm) 40.69 mm3/y vs 24.47 mm3/y, respectively (P = .315); acetabular component abduction angle (<45° vs ≥45°): 38.68 mm3/y vs 27.8 mm3/y, respectively (P = .522); acetabular anteversion (<20° vs ≥20°): 41.32 mm3/y vs 31.79 mm3/y, respectively (P = .521). There were no dislocations, mechanical failures, or revisions. There were 7 hips with volumetric wear rates ≥80 mm3/y; 1 had possible osteolysis.
  
  
  
  Larger-diameter XLPE wear was not measurably affected by liner thickness, acetabular abduction angle, or acetabular anteversion. However, there is a trend for increasing volumetric wear with increasing bearing size. Wear outliers do occur, and continued follow-up of larger-diameter XLPE bearings is warranted.
authors.affiliation: Department of Orthopaedic Surgery, Harbor-UCLA Medical Center, Torrance, California.
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Haw
authors.affiliation: Department of Orthopaedic Surgery, Harbor-UCLA Medical Center, Torrance, California.
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Battenberg
authors.affiliation: Joint Replacement Institute at St. Vincent Medical Center, Los Angeles, California.
authors.forename: Der-Chen T
authors.initials: DT
authors.lastname: Huang
authors.affiliation: Joint Replacement Institute at St. Vincent Medical Center, Los Angeles, California.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Schmalzried
mesh_terms: D000077:Acetabulum; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation; D001847:Bone Diseases; D002357:Cartilage Diseases; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology*; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography
chemical_list: D020959:Polyethylene
keywords: cross-linked polyethylene; large-diameter bearings; osteolysis; radiographic analysis; total hip arthroplasty; wear rates