title: The effect of adding tobramycin to Simplex P cement on femoral stem micromotion as measured by radiostereometric analysis: a 2-year randomized controlled trial.
abstract: BACKGROUND
  Previous in vitro research on addition of antibiotics to bone cement has found no statistically significant deterioration in mechanical properties. However, no clinical studies have compared the performance of tobramycin-laden bone cement with that of standard bone cement (Simplex P).
  
  
  METHODS
  23 patients (25 hips) were randomized to receive an Exeter (Stryker Orthopaedics) femoral stem cemented with either Simplex P (standard) or Simplex T (tobramycin-laden) cement. There were 2 years of follow-up, with scheduled radiostereometric (RSA) examinations.
  
  
  RESULTS
  All stems migrated distally and showed some degree of retroversion. No clinically significant differences in stem subsidence or retroversion were found between the Simplex T and Simplex P cement groups after 2 years. Overall subsidence was less than in previous studies, probably due to a postponed initial post-surgical examination. Rates of subsidence in both cement groups were consistent with those from previous studies of Exeter stems.
  
  
  CONCLUSIONS
  Subsidence of the femoral stem after 2 years was similar in the Simplex T (tobramycin-laden) and Simplex P (standard) groups.
authors.affiliation: Concordia Joint Replacement Group, Concordia Hip and Knee Institute, Winnipeg, Manitoba, Canada. ebohm@cjrg.ca
authors.forename: Eric
authors.initials: E
authors.lastname: Bohm
authors.forename: Martin
authors.initials: M
authors.lastname: Petrak
authors.forename: Trevor
authors.initials: T
authors.lastname: Gascoyne
authors.forename: Thomas
authors.initials: T
authors.lastname: Turgeon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation; D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000494:pharmacology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging* / Q000601:surgery; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D020366:Methylmethacrylate / Q000494:pharmacology*; D008875:Middle Aged; D011475:Prosthesis Failure / Q000187:drug effects*; D059869:Radiostereometric Analysis; D012189:Retrospective Studies; D014031:Tobramycin / Q000494:pharmacology*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D001843:Bone Cements; D020366:Methylmethacrylate; D014031:Tobramycin