title: A comparison of polyethylene wear between cobalt-chrome ball heads and alumina ball heads after total hip arthroplasty: a 10-year follow-up.
abstract: METHODS
  This is a retrospective study comparing polyethylene wear between ceramic ball heads and metal ball heads in total hip arthroplasty.
  
  
  BACKGROUND
  The ceramic-on-polyethylene bearing option has been introduced as an alternative to metal-on-polyethylene to minimize polyethylene wear debris and reduce subsequent osteolysis and aseptic loosening. However, the reported data were debatable. We designed this retrospective study to compare polyethylene wear between alumina ceramic ball heads and cobalt-chrome ball heads.
  
  
  METHODS
  Bilateral simultaneous primary total hip arthroplasty was performed in 22 patients between January 2002 and December 2002, with one side using metal-on-polyethylene bearing surface and the other side using alumina ceramic-on-polyethylene bearing surface. After 10 years of follow-up, the wear rate of polyethylene liner on both sides was measured using the Dorr method and compared.
  
  
  RESULTS
  The annual wear rate of the polyethylene liner was 0.133 mm with a standard deviation of 0.045 in the metal-on-polyethylene group and 0.056 mm with a standard deviation of 0.032 in the ceramic-on-polyethylene group. The wear rate per year was significantly lower in the ceramic-on-polyethylene group (p < 0.001).
  
  
  CONCLUSIONS
  Although the implication is still controversial, our study showed that the use of ceramic head lowered the liner wear rate.
  
  
  CONCLUSIONS
  Ceramic is harder and more resistant to scratching than cobalt-chrome. By increasing polyethylene liner survivorship and decreasing potential osteolytic response and aseptic loosening, ceramic head is a better alternative than cobalt-chrome head.
authors.affiliation: Department of the Joint and Bone Surgery, Yantaishan Hospital, Yantai 264001, Shandong Province, China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Wang
authors.forename: ShuDong
authors.initials: S
authors.lastname: Zhang
authors.forename: YuChi
authors.initials: Y
authors.lastname: Zhao
mesh_terms: D000328:Adult; D000537:Aluminum Oxide; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D002858:Chromium Alloys; D003035:Cobalt; D005260:Female; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure / Q000209:etiology; D011859:Radiography; D012189:Retrospective Studies
chemical_list: D002858:Chromium Alloys; D003035:Cobalt; D020959:Polyethylene; D000537:Aluminum Oxide