Assessment of Growth Reduction of Five Clinical Pathogens by Injectable S53P4 Bioactive Glass Material Formulations

Current Development in Biomaterials-Hydroxyapatite and Bioglass for Applications in Biomedical Field: A Review

Inorganic biomaterials, including different types of metals and ceramics are widely used in various fields due to their biocompatibility, bioactivity, and bioresorbable capacity. In recent years, biomaterials have been used in biomedical and biological applications. Calcium phosphate (CaPs) compounds are gaining importance in the field of biomaterials used as a standalone material or in more complex structures, especially for bone substitutes and drug delivery systems. The use of multiple dopants into the structure of CaPs compounds can significantly improve their in vivo and in vitro activity. Among the general information included in the Introduction section, in the first section of this review paper, the authors provided a background on the development of hydroxyapatite, methods of synthesis, and its applications. The advantages of using different ions and co-ions for substitution into the hydroxyapatite lattice and their influence on physicochemical, antibacterial, and biological properties of hydroxyapatite are also presented in this section of the review paper. Larry Hench's 45S5 Bioglass^®, commercially named 45S5, was the first bioactive glass that revealed a chemical bond with bone, highlighting the potential of this biomaterial to be widely used in biomedicine for bone regeneration. The second section of this article is focused on the development and current products based on 45S5 Bioglass^®, covering the historical evolution, importance of the sintering method, hybrid bioglass composites, and applications. To overcome the limitations of the original biomaterials, studies were performed to combine hydroxyapatite and 45S5 Bioglass^® into new composites used for their high bioactivity and improved properties. This particular type of combined hydroxyapatite/bioglass biomaterial is discussed in the last section of this review paper.

Treatment of Infection-Related Non-Unions with Bioactive Glass-A Promising Approach or Just Another Method of Dead Space Management?

The treatment of infected and non-infected non-unions remains a major challenge in trauma surgery. Due to the limited availability of autologous bone grafts and the need for local anti-infective treatment, bone substitutes have been the focus of tissue engineering for years. In this context, bioactive glasses are promising, especially regarding their anti-infective potential, which could reduce the need for local and systemic treatment with conventional antibiotics. The aim of this study was to investigate the osteoinductive and osteoconductive effects, as well as the anti-infectious potential, of S53P4 using a standardized non-union model, which had not been investigated previously. Using an already established sequential animal model in infected and non-infected rat femora, we were able to investigate bioactive glass S53P4 under realistic non-union conditions regarding its osteoinductive, osteoconductive and anti-infective potential with the use of µCT scans, biomechanical testing and histological, as well as microbiological, analysis. Although S53P4 did not lead to a stable union in the non-infected or the infected setting, µCT analysis revealed an osteoinductive effect of S53P4 under non-infected conditions, which was diminished under infected conditions. The osteoconductive effect of S53P4 remained almost negligible in histological analysis, even 8 weeks after treatment. Additionally, the expected anti-infective effect could not be demonstrated. Our data suggested that S53P4 should not be used in infected non-unions, especially in those with large bone defects.

Bioactive glass S53P4 to fill-up large cavitary bone defect after acute and chronic osteomyelitis treated with antibiotic-loaded cement beads: A prospective case series with a minimum 2-year follow-up

INTRODUCTION

Bioactive glass S53P4 (BAG-S53P4) has been used in the treatment of osteomyelitis with excellent results. The aim of this study was to evaluate the clinical and radiographic results of patients treated with use of antibiotic-loaded cement beads, followed by bone defects filling using bioglass.

METHODS

We treated a prospective series of patients presenting with acute or chronic osteomyelitis of a long bone of the upper or lower limb. The first-stage procedure involved debridement and filling of cavitary defects with antibiotic-loaded polymethylmethacrylate (PMMA) beads. When signs of infection subsided, the defects were filled with BAG-S53P4. The main outcomes assessed were the reinfection rate, need for reoperation, radiographic and functional evaluations (DASH and Lysholm scores).

RESULTS

Ten patients were included, aged between 4 and 66 years (mean 25.4 years). The source of infection was hematogenic in five cases and post-traumatic in the other five. Hematogenic infections required two debridements before filling with bioglass, whereas post-traumatic cases required only one. The time between the first debridement and the application of bioglass varied from 1 to 63 weeks (average of 17 weeks). All patients showed a favorable evolution after bioglass procedure, with no need for reoperation or relevant wound problems. The radiographic evaluation showed partial incorporation of the material and adequate bone formation, and functional scores were satisfactory in all cases.

CONCLUSION

The treatment of osteomyelitis with surgical debridement and PMMA beads, followed by filling of bone defect with BAG-S53P4, was effective in all patients evaluated, with adequate infectious control and bone regeneration. No cases required reoperation after bioglass implantation. Patients with hematogenous osteomyelitis required a greater number of debridements before filling with bioglass.