Antibiotic-Loaded Polymer-Calcium Phosphate Scaffold for Treating Orthopedic Device-Related Infection in a Rabbit...

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Infectious Diseases

Background:

• Orthopedic device-related infections (ODRI) often require complex two-stage surgical revisions.
• Current treatments involve antibiotic-loaded polymethyl methacrylate (PMMA) spacers, which are burdensome and may not prevent recurrence.
• A single-stage solution combining infection eradication and bone regeneration is highly desirable.

Purpose of the Study:

• To evaluate the efficacy of a novel 3D-printed, antibiotic-loaded, osteoconductive calcium phosphate scaffold (CPS) in a rabbit model of infected segmental bone defect.
• To compare the performance of CPS with traditional PMMA spacers and empty defects in treating ODRI.

Main Methods:

• A 5-mm segmental radius defect model was created in rabbits and inoculated with Staphylococcus aureus.
• After 4 weeks, defects were treated with empty control, PMMA with gentamicin, rifampicin-loaded CPS, or vancomycin-loaded CPS.
• Systemic antibiotics were administered in most groups; one CPS group received only local antibiotics.
• Outcomes were assessed via quantitative bacteriology and histopathology at 8 weeks post-revision.

Main Results:

• Antibiotic-loaded scaffolds (PMMA-Gentamicin and CPS-Rifampicin) with systemic antibiotics reduced bacterial counts compared to controls.
• PMMA-Gentamicin significantly reduced Colony Forming Units (CFUs) (p=0.0486) and lowered infection rates from 80% to 50%.
• CPS-Vancomycin without systemic antibiotics showed a lower infection rate but comparable CFUs to controls, indicating local antibiotics alone are insufficient.

Conclusions:

• While PMMA-Gentamicin offered superior infection eradication, it lacks bone reconstruction capabilities.
• Antibiotic-loaded CPS demonstrated a reduction in infection rates and offers the potential for bone healing in a single stage.
• Further research into optimized antibiotic-loaded CPS formulations is warranted for effective ODRI management.