The effect of adding tobramycin to Simplex P cement on femoral stem micromotion as measured by radiostereometric analysis: a 2-year randomized controlled trial

Acta Orthop. 2012 Apr;83(2):115-20. doi: 10.3109/17453674.2011.652885. Epub 2012 Jan 17.


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).

Patients and 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.

Interpretation: Subsidence of the femoral stem after 2 years was similar in the Simplex T (tobramycin-laden) and Simplex P (standard) groups.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anti-Bacterial Agents / pharmacology
  • Arthroplasty, Replacement, Hip / instrumentation
  • Biomechanical Phenomena
  • Bone Cements / pharmacology*
  • Female
  • Femur / diagnostic imaging*
  • Femur / surgery
  • Follow-Up Studies
  • Hip Joint / diagnostic imaging
  • Hip Joint / surgery
  • Hip Prosthesis*
  • Humans
  • Longitudinal Studies
  • Male
  • Methylmethacrylate / pharmacology*
  • Middle Aged
  • Prosthesis Failure / drug effects*
  • Radiostereometric Analysis*
  • Retrospective Studies
  • Tobramycin / pharmacology*
  • Treatment Outcome


  • Anti-Bacterial Agents
  • Bone Cements
  • Methylmethacrylate
  • Tobramycin