SLR - March 2017 - John Borzok

Estimation of Drug Absorption in Antibiotic-Soaked Bone Grafts

Reference: Shah MR, Patel RR, Solanki RV, Gupta SH. Estimation of Drug Absorption in Antibiotic-Soaked Bone Grafts. Indian J Orthop. 2016 Nov-Dec; 50(6):669–676

Scientific Literature Review

Reviewed By: John Borzok, DPM
Residency Program: The University Hospital of Newark, NJ

Podiatric Relevance: What is the optimum duration, strength and volume of antibiotic solution required for dipping bone grafts at room temperature prior to the use?

Methods: Bone shavings from 60- to 70-year-old individuals who are undergoing total knee replacements were obtained intraoperatively. The bone material was morcellized, pulse lavaged, stored, frozen to -80 degrees Celsius and transported to the lab for testing. Each bone sample was then utilized with Gentamycin and Vancomycin in different volumes, strengths and times to test saturations and minimal inhibitory concentration (MIC) levels. For analysis, a liquid chromatography mass spectrometry tandem mass spectrometry (LC-MS/MS) system was utilized.

Results: With regards to Gentamicin and Vancomycin, 0.2 mL of two percent solution (20 mg/mL)/100 g of bone is the optimal solution. The optimal duration of dipping was up to 30 minutes in order to achieve concentration of five times higher the MIC values.

Conclusions: In areas of poor vascularity by either trauma, healed infection, failed hardware or infected hardware, the addition of a bone graft can rekindle or be a nidus for infection. After removal of antibiotic cement spacers, or in acute compound fracture defects, the chances of infection remain high when inserting autograft and allograft material. Not been much research has been done in the area of soaking bone grafts in antibiotics for the same reasoning behind antibiotic beads and antibiotic cement spacers. This method of dipping the graft in antibiotics would help load the graft to five times the MIC values to retard infection.  

This information may be of clinical importance to a foot and ankle surgeon treating a patient who may need a large bone graft to fill a defect. Soaking the bone graft in an antibiotic solution as described in this study may prevent further infection. 

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