Gentamicin release from old cement during revision hip arthroplasty

Area of Science:

• Orthopedic Surgery
• Infectious Diseases
• Biomaterials

Background:

• Bone cement containing gentamicin is widely used in orthopedic procedures.
• Fracturing of gentamicin-loaded bone cement during revision surgery can lead to antibiotic release.
• This release may contaminate intraoperative samples, potentially compromising microbiological assessments.

Purpose of the Study:

• To investigate the extent of gentamicin release from bone cement during revision hip replacement surgery.
• To determine the impact of cement disruption on gentamicin concentrations in surgical samples.
• To assess the implications for microbiological analysis in revision orthopedic procedures.

Main Methods:

• Prospective study involving five patients undergoing revision hip replacement with prior gentamicin-loaded cement.
• Collection of joint fluid, tissue, and cement samples before and after cement disruption.
• Quantification of gentamicin concentrations in all collected samples.

Main Results:

• Low gentamicin concentrations were detected in pre-disruption samples (except one joint fluid sample).
• Post-disruption samples showed significantly higher gentamicin concentrations, sufficient to inhibit microbial growth.
• High gentamicin levels persisted in bone cement up to ten years after insertion.

Conclusions:

• Microbiological assessment of samples taken after cement disruption is unreliable due to gentamicin contamination.
• Surgical specimens for microbiological analysis should be collected as early as possible during revision procedures.
• The study highlights the importance of timing sample collection to avoid antibiotic interference.