title: Ten-year follow-up of primary straight-stem prosthesis (MEM) made of titanium or cobalt chromium alloy.
abstract: BACKGROUND
  An increased revision rate of cemented titanium stems compared with cobalt chromium stems has been described after a short follow-up. In this paper, the minimum 10-year outcome after the implantation of titanium (Ti) and cobalt chromium ME (CoCr) Mueller straight-stem prostheses is analyzed in order to estimate the prognosis of the patients who were not revised.
  
  
  METHODS
  . A total of 272 (Ti) straight stems were implanted between 1987 and 1990, and 161 (CoCr) straight stems were implanted from 1984 to 1987. Clinical and radiological checks were carried out prospectively after 1, 2, 5, and 10 years.
  
  
  RESULTS
  The survival rate concerning aseptic loosening of the stem after 5 years was 92.8% (Ti)/100% (CoCr) and after 10 years 80.9%/98.2%. Thirty-six (Ti)/2 (CoCr) patients required revision of the stem due to aseptic loosening. The revision rate per year of the Ti stems increased until 7 years postoperatively and decreased thereafter. At the 10-year follow-up, 107 Ti and 84 CoCr implants were checked, and the subjective and clinical parameters did not differ between the two groups.
  
  
  CONCLUSIONS
  Except for an increased subsidence rate of the stems in the Ti (31%) versus the CoCr group (16%), there was no statistically significant difference in the clinical and radiological outcomes.
authors.affiliation: Orthopaedic Department, Kantonsspital Liestal, Rheinstrasse 26, 4410 Liestal, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Schweizer
authors.forename: U
authors.initials: U
authors.lastname: Riede
authors.forename: T B
authors.initials: TB
authors.lastname: Maurer
authors.forename: P E
authors.initials: PE
authors.lastname: Ochsner
mesh_terms: D000368:Aged; D002858:Chromium Alloys; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D012086:Reoperation; D014025:Titanium
chemical_list: D002858:Chromium Alloys; D014025:Titanium