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

Abstract Background Steroids such as glucocorticoid have been widely used for their excellent anti-inflammatory, anti-immune, and anti-shock properties. However, the long-term use in high doses has been found to cause necrosis of femoral head and other serious adverse reactions. Thus, it is of great importance to safely use these medications on patients without inducing bone necrosis. Methods In this preclinical study, we examined the effects of erythropoietin (EPO) to attenuate the induction of steroid-induced femoral bone necrosis using rats to build up the in-vivo models. Rats were randomly divided into three groups: negative control group (group A), disease group (group B), and EPO group (group C). 20 mg/kg methylprednisolone was administrated into group B and group C for 6 weeks with two intramuscular injections per week per rat. Group C was further given daily intraperitoneal injections of rHuEPO during this period. Group A received only injection of saline at the same schedule. 12 weeks after the initial drug administration, the rats’ femoral tissues were harvested for HE staining, immunohistochemistry studies for PECAM-1(also CD31) expression and Western Blotting for VEGF expression. Results Histology studies showed that compared with the disease group, EPO group had significant improvement and bone morphology being much closer to the negative control group. Immunohistochemical studies revealed that EPO group had statistically much more expression of PECAM-1 than the other groups did. Western Blot demonstrated that the EPO group had significantly higher VEGF expression than the disease group. Conclusion Results suggested that simultaneous injection of EPO could partially prevent steroid-induced ANFH.