title: Primary cementless total hip arthroplasty with second-generation metal-on-metal bearings: a concise follow-up, at a minimum of seventeen years, of a previous report.
abstract: BACKGROUND
  Second-generation, metal-on-metal bearings were introduced in 1988, to reduce wear and avoid polyethylene particle-induced osteolysis from total hip arthroplasty. In 2007, we reported the long-term results of ninety-eight patients (105 hips) who underwent primary cementless total hip arthroplasty involving the use of a prosthesis with a high-carbide-concentration, metal-on-metal articulating surface between November 1992 and May 1994. The present study gives an update on this patient cohort.
  
  
  METHODS
  At a minimum of seventeen years postoperatively, forty-nine patients (fifty-two hips) were available for follow-up examination. We retrospectively evaluated clinical and radiographic results as well as serum metal concentration. The mean patient age at the time of the index arthroplasty was fifty-six years.
  
  
  RESULTS
  Three cups (6% of the hips) and one stem (2% of the hips) were revised because of aseptic loosening of the implants combined with focal osteolysis. At the time of the latest follow-up evaluation, the mean Harris hip score was 88.8 points, and the mean University of California Los Angeles (UCLA) activity score was 6.7 points. The cumulative rate of implant survival, with aseptic failure as the end point, was 93.0% at 18.8 years. The median serum cobalt concentration in patients whose hip implant was the only source of cobalt was 0.70 μg/L (range, 0.4 to 5.1 μg/L), showing no increase in the value as noted at a minimum of ten years of follow-up.
  
  
  CONCLUSIONS
  The clinical and radiographic results of our study, which, to our knowledge, represent the longest duration of follow-up for a series of cementless total hip arthroplasties with use of a 28-mm metal-on-metal bearing, continue to be comparable with the results observed for other hard-on-hard bearings.
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: R
authors.initials: R
authors.lastname: Lass
authors.affiliation: Sanatorium Hera, Löblichgasse 14, A-1090 Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Grübl
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: A
authors.initials: A
authors.lastname: Kolb
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: S
authors.initials: S
authors.lastname: Domayer
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: C
authors.initials: C
authors.lastname: Csuk
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: B
authors.initials: B
authors.lastname: Kubista
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: A
authors.initials: A
authors.lastname: Giurea
authors.affiliation: Department of Orthopedics, Medical University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. E-mail address for R. Lass: richard.lass@meduniwien.ac.at.
authors.forename: R
authors.initials: R
authors.lastname: Windhager
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D061825:Metal-on-Metal Joint Prostheses; D008875:Middle Aged; D011474:Prosthesis Design; D012189:Retrospective Studies; D013997:Time Factors; D055815:Young Adult