title: Metal-on-metal bearings in cementless primary total hip arthroplasty.
abstract: One hundred cementless titanium primary total hip arthroplasties with 28 mm Metasul bearings were prospectively studied (osteoarthritis in 76% of hips, mean age 59.6 years). Ninety-eight were reviewed after a 6-year average follow-up (range, 17-126 months) with clinical results graded excellent and good in 97%. One femoral component was revised for aseptic loosening at 7.8 years. Postoperative cobalt level was higher than the upper "normal" value (5 microg/L in whole blood) for 16 cases. No significant relationship could be established between cobalt concentration increase and any demographic or surgical data, including activity level, except anteversion of the cup >25 degrees. In this early experience, impingement due to a head sleeve has been the main cause of dislocation and failure, and systemic cobalt survey appeared to be a good indicator of metal-on-metal bearing mechanical behavior.
authors.affiliation: Department of Orthopaedic Surgery, Clinique de l'Yvette, Longjumeau, France.
authors.forename: Christian P
authors.initials: CP
authors.lastname: Delaunay
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D003035:Cobalt / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008670:Metals; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016896:Treatment Outcome
chemical_list: D008670:Metals; D003035:Cobalt