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Slow-releasing potential of vancomycin-loaded porous hydroxyapatite blocks implanted into MRSA osteomyelitis
Tomoyuki Saito1, Ryohei Takeuchi, Kazuo Hirakawa
1Department of Orthopaedic Surgery, Yokohama City University School of Medicine, Japan. t_saito@yokohama-cu.ac.jp
Abstract:
Although antibiotic-loaded hydroxyapatite blocks have been used for the treatment of chronic osteomyelitis, their long-term potential for releasing antibiotic into human bones is not well known. Five patients with chronic osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) infection were effectively treated with local implantation of vancomycin-loaded hydroxyapatite blocks. Blocks were removed during the following reconstructive surgeries when the releasing capability of the blocks, and the bacteriocidal activity of the remaining vancomycin in these blocks could be evaluated. Vancomycin was rapidly released within 1 month after implantation, and by 3 months 90% of vancomycin had leaked from the blocks. At 18 months vancomycin still remained in a bacteriocidal form in the hydroxyapatite blocks, though the blocks had no releasing potential or the eluted vancomycin had been changed to a different form. Vancomycin-loaded porous hydroxyapatite blocks would be useful for the treatment of chronic osteomyelitis or implant-associated osteomyelitis due to MRSA.
Insights
Vancomycin-loaded hydroxyapatite blocks effectively treated chronic osteomyelitis caused by MRSA. While most vancomycin released early, it remained bactericidal in blocks for 18 months, showing long-term therapeutic potential.
Area of Science:
- Orthopedic Surgery
- Infectious Diseases
- Biomaterials Science
Background:
- Chronic osteomyelitis, particularly MRSA infections, poses treatment challenges.
- The long-term antibiotic release from hydroxyapatite blocks is not fully understood.
Purpose of the Study:
- To evaluate the antibiotic release profile and sustained bactericidal activity of vancomycin-loaded hydroxyapatite blocks in patients with chronic osteomyelitis.
- To assess the efficacy of these blocks in treating methicillin-resistant Staphylococcus aureus (MRSA) bone infections.
Main Methods:
- Local implantation of vancomycin-loaded hydroxyapatite blocks in five patients with chronic MRSA osteomyelitis.
- Removal of blocks during reconstructive surgery for evaluation of drug release and remaining antibiotic activity.
- Analysis of vancomycin release kinetics and bactericidal activity over time.
Main Results:
- Effective treatment of MRSA osteomyelitis in all five patients.
- Rapid vancomycin release within the first month, with 90% eluted by 3 months.
- Sustained bactericidal activity of residual vancomycin within the blocks for up to 18 months, even after release potential diminished.
Conclusions:
- Vancomycin-loaded porous hydroxyapatite blocks demonstrate significant potential for treating chronic osteomyelitis and implant-associated osteomyelitis caused by MRSA.
- The blocks provide both initial rapid drug delivery and long-term sustained bactericidal activity.
- These findings support the clinical utility of vancomycin-loaded hydroxyapatite blocks for challenging bone infections.