title: Zirconia versus Co-Cr femoral heads in total hip arthroplasty: early assessment of wear.
abstract: Polyethylene wear and associated osteolysis are major limitations to the long-term success of total hip arthroplasty. In vitro laboratory studies suggest polyethylene wear in THA may be substantially reduced with ceramic femoral heads. We evaluated the potential value of zirconia ceramic on conventional polyethylene as an "alternative bearing" for total hip arthroplasty in a prospective, randomized clinical trial in comparison with femoral heads made of Co-Cr-Mo. Patients were evaluated with standardized clinical outcome instruments, and measurement of head penetration was performed with computerized wear measurement software. Study enrollment was halted because of a recall of the zirconia heads. At that time, 30 total hip arthroplasties with Co-Cr-Mo heads and 30 total hip arthroplasties with zirconia heads had been performed. Mean followup was similar for both groups (Co-Cr- Mo = 51.7 months; zirconia = 51.2 months). The mean annual head penetration rate was low and similar for both groups (Co-Cr-Mo = 0.060 mm/year; and zirconia = 0.055 mm/year). In view of the recently reported potential for zirconia ceramics to undergo monoclinic phase transformation in vivo, with resultant increased fracture risk and degradation of wear properties, we do not recommend use of zirconia femoral heads as an "alternative bearing" for total hip arthroplasty.
authors.affiliation: Case Western Reserve University School of Medicine, Division of Joint Reconstruction and Arthritis Surgery, University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, OH 44106, USA. matthew.kraay@uhhs.com
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kraay
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Thomas
authors.forename: Clare M
authors.initials: CM
authors.lastname: Rimnac
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fitzgerald
authors.forename: Victor M
authors.initials: VM
authors.lastname: Goldberg
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects; D002858:Chromium Alloys; D005260:Female; D005270:Femur Head; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology / Q000473:pathology; D020959:Polyethylene; D011475:Prosthesis Failure; D015040:Zirconium
chemical_list: D002858:Chromium Alloys; D020959:Polyethylene; D015040:Zirconium; C028541:zirconium oxide