title: Cementless metal-on-metal versus ceramic-on-polyethylene hip arthroplasty in patients less than fifty years of age: a comparative study with twelve to fourteen-year follow-up.
abstract: BACKGROUND
  We previously reported the outcomes of a case-control study, at a minimum of five years of follow-up, comparing metal-on-metal and ceramic-on-polyethylene bearings for cementless primary hip arthroplasty in active patients below the age of fifty years. This report is an update on these groups after a minimum duration of follow-up of twelve years.
  
  
  METHODS
  Thirty-nine metal-on-metal cementless hip replacements with a 28-mm-diameter Metasul articulation were compared with a control group that included thirty-nine cementless ceramic-on-polyethylene hip replacements performed with a 28-mm-diameter head. The Metasul group included thirty patients with a mean age of forty years (range, twenty-three to forty-nine years), and the control group included thirty-two patients with a mean age of forty-one years (range, fifteen to forty-nine years). The groups were matched for age, activity level, preoperative Harris hip score, acetabular cup diameter, and indication for hip arthroplasty. All patients had a high level of activity, with 82% rated as grade IV or V according to the Devane scale.
  
  
  RESULTS
  After a mean duration of follow-up of thirteen years (twelve to fourteen years), only one hip (3%) had asymptomatic acetabular osteolysis and no hip (0%) had been revised in the metal-on-metal group, whereas eighteen hips (46%) had osteolysis and eleven hips (28%) had been revised because of wear or osteolysis in the ceramic-on-polyethylene group (p < 0.003). In the metal-on-metal group, the median Co concentration in the whole blood was 0.95 μg/L (0.4 to 4.8 μg/L) and the median Cr concentration was 1.2 μg/L (0.1 to 5.6 μg/L). The twelve-year survival rate (with reoperation for any reason as the end point) was 100% in the metal-on-metal group and 70% (95% confidence interval, 63% to 77%) in the ceramic-on-polyethylene group (p = 0.003).
  
  
  CONCLUSIONS
  After twelve to fourteen years of follow-up, metal-on-metal implants demonstrated better radiographic and survival results than ceramic-on-polyethylene implants in young, very active patients. Current wrought metal-on-metal implants with a 28-mm-diameter head and high carbide concentration did not produce the high rates of osteolysis and allergic reactions that may be observed with cast low-carbide metal-on-metal bearings after a shorter duration of follow-up.
authors.affiliation: Roger Salengro Hospital, Centre Hospitalier Régional Universitaire de Lille, 2 avenue Oscar Lambret, 59037 Lille CEDEX, France. hemigaud@nordnet.fr
authors.forename: Henri
authors.initials: H
authors.lastname: Migaud
authors.forename: Sophie
authors.initials: S
authors.lastname: Putman
authors.forename: Nicolas
authors.initials: N
authors.lastname: Krantz
authors.forename: Laurent
authors.initials: L
authors.lastname: Vasseur
authors.forename: Julien
authors.initials: J
authors.lastname: Girard
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000704:Analysis of Variance; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D016022:Case-Control Studies; D002516:Ceramics; D016009:Chi-Square Distribution; D002857:Chromium / Q000097:blood; D003035:Cobalt / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D018709:Statistics, Nonparametric; D015996:Survival Rate; D016896:Treatment Outcome
chemical_list: D002857:Chromium; D003035:Cobalt; D020959:Polyethylene