Local Antibiotic Delivery Systems and Their Applications in Orthopaedic Surgery

Area of Science:

• Orthopaedic surgery
• Biomaterials science
• Infectious disease management

Background:

• Local antibiotic delivery is vital for managing periprosthetic and fracture-related infections, achieving high concentrations at the infection site while minimizing systemic toxicity.
• Polymethyl methacrylate (PMMA) was the first material used for local antibiotic delivery in orthopaedics, providing reliable delivery above the Minimum Inhibitory Concentration (MIC) for heat-stable antibiotics.
• Challenges with PMMA include potential weakening of the cement with excessive antibiotic loading and the need for secondary surgery to replace it with bone grafts for bone defects.

Purpose of the Study:

• To review and compare various local antibiotic delivery systems used in orthopaedic surgery.
• To highlight the advantages and limitations of different biomaterials as antibiotic carriers.
• To discuss their efficacy in managing bone infections and promoting bone healing.

Main Methods:

• Review of existing literature on local antibiotic delivery systems in orthopaedics.
• Analysis of properties of different biomaterials: Polymethyl methacrylate (PMMA), Calcium sulfate (CaSO4), Hydroxyapatite (HA), Tricalcium phosphate (Ca3(PO4)2), hydrogels, and antibiotic-impregnated bone grafts.
• Evaluation of antibiotic release profiles, biocompatibility, biodegradability, osteoconductivity, and clinical outcomes.

Main Results:

• Calcium sulfate (CaSO4) and hydroxyapatite (HA) combinations offer high antibiotic delivery and better bone conversion than CaSO4 alone, suitable for smaller defects.
• Tricalcium phosphate (Ca3(PO4)2) cements are biocompatible and biodegradable, enabling prolonged antibiotic release and effective bone formation.
• Hydrogels and defensive antibacterial coatings (DAC) provide physical barriers, reduce bacterial adhesion, and can promote bone healing.
• Antibiotic-impregnated bone grafts offer maximal bone healing potential with effective local antibiotic delivery.

Conclusions:

• Multiple biomaterials serve as effective local antibiotic delivery systems in orthopaedics, each with unique properties and applications.
• The choice of material depends on the specific clinical scenario, including defect size, infection type, and need for bone regeneration.
• These systems are critical for improving outcomes in periprosthetic and fracture-related infections, reducing complications, and enhancing bone healing.