Evaluation of delayed effect of intra-articular injection of cefazolin, gentamicin and vancomycin on articular cartilage: an experimental study in rabbits

Antibiotics are the most common additives used in irrigation solutions for open fractures. Nonetheless, there have been few studies exploring the effects of antibiotics on articular cartilage. The purpose of this study was to evaluate the delayed effect of intra-articular injection of cefazolin, gentamicin and vancomycin on articular cartilage. Regarding the characteristics of antibiotic solutions, we proposed they may have potential toxicity on articular cartilage and this effect may be manifested as a delayed phenomenon due to changes in matrix and cell viability. A sample of 20 rabbits was chosen and assigned into 4 groups (each containing 5 animals). A course of antibiotics including gentamicin, vancomycin and cefazolin was injected in both knees of test rabbits. Normal saline was injected to controls. After 8 weeks, articular cartilage of distal femurs was harvested and analyzed using confocal microscopy and Real time PCR. According to confocal microscopy results, gentamicin and vancomycin had significant decrease in live chondrocyte cell number, however, cefazolin had no effect. Quantitative analysis showed no significant difference between antibiotics and control group. We found that cefazolin can be safely used for intra-articular injections, but vancomycin and gentamicin should be used cautiously.