# Prolonged efficacy of cefazolin in intraosseous regional prophylaxis for total knee arthroplasty: a rabbit model study

## TL;DR

This study shows that injecting cefazolin directly into bone during knee surgery keeps effective antibiotic levels longer than traditional methods in a rabbit model.

## Contribution

The study demonstrates prolonged efficacy of intraosseous cefazolin for antibiotic prophylaxis in total knee arthroplasty.

## Key findings

- IORA of cefazolin resulted in significantly higher plasma concentrations at all timepoints compared to intravenous administration.
- Cefazolin concentrations remained above the minimum inhibitory concentration for extended durations with IORA.
- IORA provides sustained effective antibiotic levels during total knee arthroplasty in a rabbit model.

## Abstract

A novel approach known as intraosseous regional administration (IORA) has emerged as a technique for delivering prophylactic antibiotics, and it results in higher tissue concentrations around the knee. It is hypothesized that IORA of cefazolin for antibiotic prophylaxis during total knee arthroplasty will result in sustained effective levels for a longer duration. The aim of the current study was to investigate temporal changes in peri-knee cefazolin blood concentrations after IORA of cefazolin.

Twelve rabbits were randomly divided into two groups, with six rabbits in each group. In control group a single intravenous bolus injection of cefazolin (10 mL, 100 mg) was administered into the marginal ear vein. In experimental groupexperimental group the same dose of cefazolin was injected into the left tibial marrow cavity after tourniquet inflation at the base of the left thigh. Blood samples were collected periodically at different timepoints, and cefazolin concentrations were determined.

The intraosseous treatment resulted in significant differences in plasma cefazolin concentrations at all timepoints. Experimental group exhibited higher plasma cefazolin concentrations than control group.

Cefazolin in intraosseous regional prophylaxis exhibits effectiveness in intraoperative antibiotic prophylaxis by maintaining concentrations above the minimum inhibitory concentration for extended durations, rather than relying solely on high concentrations.