Antibacterial Bioactive Glass, S53P4, for Chronic Bone Infections – A Multinational Study

Injectable vancomycin-loaded silk fibroin/methylcellulose containing calcium phosphate-based in situ thermosensitive hydrogel for local treatment of osteomyelitis: Fabrication, characterization, and in vitro performance evaluation

The conventional treatment of osteomyelitis with antibiotic-loaded nondegradable polymethylmethacrylate (ATB-PMMA) beads has certain limitations, including impeded bone reconstruction and the need for secondary surgery. To overcome this challenge, this study aimed to develop and characterize an injectable vancomycin-loaded silk fibroin/methylcellulose containing calcium phosphate-based in situ thermosensitive hydrogel (VC-SF/MC-CAPs). The VC-SF/MC-CAPs solution can be easily administered at room temperature with a low injectability force of ≤30 N and a high vancomycin (VC) content of ~96%. Additionally, at physiological temperature (37 °C), the solution could transform into a rigid hydrogel within 7 minutes. In vitro drug release performed under both physiological (pH 7.4) and infection conditions (pH 4.5) revealed a prolonged release pattern of VC-SF/MC-CAPs following the Peppas-Sahlin kinetic model. In addition, the released VC from VC-SF/MC-CAPs hydrogels exhibited antibacterial activity against Staphylococcus aureus for a period exceeding 35 days, as characterized by the disk diffusion assay. Furthermore, at pH 7.4, the VC-SF/MC-CAPs demonstrated >60% degradation within 35 days. Importantly, when exposed to physiological pH conditions, CAPs are transformed into bioactive hydroxyapatite, which benefits bone formation. Therefore, VC-SF/MC-CAPs showed significant potential as a local drug delivery system for treating osteomyelitis.

Distally based sural flaps for soft tissue defects following traumatic osteomyelitis of lower leg and foot

This retrospective study aimed to determine the incidence and risk factors for osteomyelitis recurrence and present our experiences in treating traumatic osteomyelitis in the lower leg and foot. We retrospectively reviewed data from 174 patients with distally based sural flaps for treating traumatic osteomyelitis with soft tissue defects in the lower leg and foot from November 2003 to February 2021. Possible risk factors for osteomyelitis recurrence were compared between the osteomyelitis control and recurrence groups. A total of 162 (93.1%) flaps survived uneventfully, while 12 (6.9%) flaps developed partial necrosis. Five patients had a bone defect with an average length of 5 cm. The free vascularized bone grafts were performed in two patients, and bone transportations were performed in three patients. All patients were followed up with an average period of 72.8 months. There were 152 patients (87.4%) in control group and 22 patients (12.6%) in recurrence group. The recurrence rates of osteomyelitis were significantly higher when the patient's age was 40 years or more and the duration was 10 weeks or more (P < 0.05). Cierny-Mader (C-M) classification type IV osteomyelitis was also significantly associated with osteomyelitis recurrence (p = 0.049). This flap combined with appropriate osteomyelitis treatment was an effective method to treat traumatic osteomyelitis of lower leg and foot with a soft tissue defect. Both patient age ≥ 40 years old and C-M type IV osteomyelitis were nonnegligible risk factors for osteomyelitis recurrence.

Exploring versatile applications of a vacuum-assisted bone harvester in orthopedic surgery

BACKGROUND

Orthopedic procedures often require removing bone or pathological tissue, with traditional methods involving instruments like curettes and rongeurs. However, these methods can be time-consuming and lead to increased blood loss. To mitigate these side effects, vacuum-assisted tools have been developed to aid in tissue removal. These devices enable surgeons to suction tissue without discarding it, potentially improving outcomes in conditions such as osteomyelitis or tumor removal while enabling collection of the material for downstream applications. Despite limited research, vacuum-assisted devices show promise beyond bone marrow harvesting. This study assesses infection and clearance rates, estimated blood loss, and total procedure time associated with the use of vacuum-assisted tissue removal, with a goal to understand if these devices can be used for tissue removal across a variety of pathologic conditions.

METHODS

A retrospective cohort study was conducted on patients undergoing orthopedic procedures with the Avitus® Bone Harvester repurposed from its original design from December 1, 2021, to July 1, 2023. Procedures were categorized into oncology, and debridement for infection cases. Infection cases were further categorized into those secondary to trauma and those involving primary infections (osteomyelitis and periprosthetic joint infection). Clinical variables, including demographics, intraoperative details, complications, and follow-up, were reviewed. Statistical analysis included descriptive statistics computed with R Studio.

RESULTS

The study included 44 patients, with debridement for infection cases being the most common (primary infection: 45.5%; infection secondary to trauma: 18.1%), followed by oncology cases (36.4%). In all oncology cases, a definitive diagnosis was established using the device, and no post-operative infections were reported. The infection clearance rate was 85.0% for primary infection cases and 50.0% for cases of infection following trauma. Across the entire cohort, the average blood loss was 314.52 mL (sd: 486.74), and the average total procedure time was 160.93 min (sd: 91.07). The overall reoperation rate was 47.7%, with an unplanned reoperation rate of 11.4%.

CONCLUSION

The vacuum-assisted bone harvester was effectively utilized in a wide range of debridement and curettage procedures across diverse orthopedic surgeries. In oncology cases, the device enabled effective tissue removal with comparable recurrence rates, demonstrating its potential to minimize contamination while preserving tissue for accurate diagnoses. Additionally, a high rate of osteomyelitis eradication was observed in debridement for primary infection cases (85%). Despite the relatively high reoperation rate of 47.7%, it is crucial to interpret this figure within the context of the varied reasons for reoperation. Many of these reoperations were planned as part of a staged approach to treatment or were unrelated to the device's performance. It is crucial to acknowledge that isolating the device's contribution to these results can be difficult. The utilization of the device should be guided by considerations of cost-effectiveness and patient-specific risk factors.

The Concept of Treatment for Surgical Infection in the Hindfoot

Background

Chronic osteomyelitis of the calcaneus (OC) and open infected calcaneal fractures, especially when complicated by infected soft tissue defects, present significant surgical challenges. Accepted recommendations for the surgical treatment of this pathology are yet to be established.

Methods

Drawing from our experience and the consensus among experts, we have developed a concept for selecting optimal, well-known surgical approaches based on the specific pathologic presentation. This concept distinguishes 4 main forms of hindfoot infection: infected wounds, open infected fractures, OC, and their mixed forms. Patients with conditions that could confound the treatment outcomes, such as diabetes mellitus and neurotrophic diseases, were excluded from this analysis. We present a retrospective analysis of the treatment outcomes for 44 patients (4 women and 40 men) treated between 2009 and 2022 using some refined surgical techniques. Treatment success was evaluated based on the absence of disease recurrence within a 2-year follow-up, the avoidance of below-knee amputations, and the restoration of weightbearing function.

Results

The treatment results were considered through the prism of our proposed concept and according to the Cierny-Mader classification. There were 4 instances of disease recurrence, necessitating 6 additional surgeries, 2 of which (4.5% of the patient cohort) resulted in amputations. In the remaining cases, we were able to restore weightbearing function and eliminate the infection through reconstructive surgeries, employing skin grafts when necessary.

Conclusion

Surgical infections of the hindfoot area remain a significant challenge. The strategic concept we propose for surgical decision making, tailored to the specific pathology, represents a potential advancement in addressing this challenge. This framework could provide valuable guidance for orthopaedic surgeons in their clinical decision-making process.

Level of Evidence

Level IV, case series.

Current application and future perspectives of antimicrobial degradable bone substitutes for chronic osteomyelitis

Chronic osteomyelitis remains a persistent challenge for the surgeons due to its refractory nature. Generally, treatment involves extensive debridement of necrotic bone, filling of dead space, adequate antimicrobial therapy, bone reconstruction, and rehabilitation. However, the optimal choice of bone substitute to manage the bone defect remains debatable. This paper reviewed the clinical evidence for antimicrobial biodegradable bone substitutes in the treatment of osteomyelitis in recent years. Indeed, this combination was proved to eradicate infection and facilitate bone reconstruction, which might reduce the cost and hospital stay. Handling was associated with increased risk of unwanted side effect to affect bone healing. The study provides some valuable insights into the clinical evaluation of treatment outcomes in the aspects of infection eradication, bone reconstruction, and complications caused by materials. However, achieving complete infection eradication and subsequently perfect bone reconstruction remains challenging in compromised conditions, hence advanced innovative bone substitutes are imperative. In this review, we mainly focus on the desired functional effects of advanced bone substitutes on infection eradication and bone reconstruction from the future perspective. Handling property was optimized to simplify surgery process. It is expected that this review will provide an important opportunity to enhance the understanding of the design and application of innovative biomaterials to synergistically eradicate infection and restore integrity and function of bone.

Clinical outcomes and complications of S53P4 bioactive glass in chronic osteomyelitis and septic non-unions: a retrospective single-center study

INTRODUCTION

Dead space management following debridement surgery in chronic osteomyelitis or septic non-unions is one of the most crucial and discussed steps for the success of the surgical treatment of these conditions. In this retrospective clinical study, we described the efficacy and safety profile of surgical debridement and local application of S53P4 bioactive glass (S53P4 BAG) in the treatment of bone infections.

METHODS

A consecutive single-center series of 38 patients with chronic osteomyelitis (24) and septic non-unions (14), treated with bioactive glass S53P4 as dead space management following surgical debridement between May 2015 and November 2020, were identified and evaluated retrospectively.

RESULTS

Infection eradication was reached in 22 out of 24 patients (91.7%) with chronic osteomyelitis. Eleven out of 14 patients (78.6%) with septic non-union achieved both fracture healing and infection healing in 9.1 ± 4.9 months. Three patients (7.9%) developed prolonged serous discharge with wound dehiscence but healed within 2 months with no further surgical intervention. Average patient follow-up time was 19.8 months ± 7.6 months.

CONCLUSION

S53P4 bioactive glass is an effective and safe therapeutic option in the treatment of chronic osteomyelitis and septic non-unions because of its unique antibacterial properties, but also for its ability to generate a growth response in the remaining healthy bone at the bone-glass interface.

Effect of Thermal Treatments and Ion Substitution on Sintering and Crystallization of Bioactive Glasses: A Review

Bioactive glasses (BGs) are promising materials for bone regeneration due to their ability to bond with living bone tissue. However, thermal stability and mechanical properties of BGs need improvement for better clinical performance. In this paper, we present an overview of the influence of different ions on the sintering and crystallization of BGs. Specifically, this review focuses on the impact of thermal treatments on the crystallization of 45S5 and other significant BG compositions. Potential applications of these thermally treated BGs, such as scaffolds, BG-based composites, and thermally sprayed coatings, are explored. Moreover, the substitution of ions has been investigated as a method to enhance the thermal properties of BGs. Notably, zinc, potassium, and strontium have been studied extensively and have demonstrated promising effects on both the thermal and the mechanical properties of BGs. However, it is important to note that research on ion inclusion in BGs is still in its early stages, and further investigation is necessary to fully comprehend the effects of different ions on sintering and crystallization. Therefore, future studies should focus on optimizing the ion substitution method to improve the thermal, mechanical, and even biological properties of BGs, thereby enhancing their potential for various biomedical applications.

Dead space management strategies in the treatment of chronic osteomyelitis: a retrospective review

PURPOSE

Dead space management is critically important during the treatment of chronic osteomyelitis. Many dead space management strategies are available, each with their respective advantages and shortcomings. This study aims to present the outcomes and complications of dead space management strategies employed in the treatment of chronic osteomyelitis at a single tertiary level musculoskeletal unit.

METHODS

A retrospective review of dead space management strategies employed at a tertiary-level musculoskeletal infection unit was conducted. Patients of any age treated for chronic osteomyelitis of the appendicular skeleton with a minimum follow-up of 6 months were included in the study. Data were collected regarding patient demographics, aetiology and site of infection, dead space management strategy employed, follow-up period and outcome in terms of resolution of infection.

RESULTS

A final cohort of 132 patients underwent surgical treatment with a dedicated dead space management strategy for chronic osteomyelitis of the appendicular skeleton. Eleven patients (8%) experienced a recurrence of infection. Seven patients (63%) with recurrence were type B hosts, while four patients (37%) were type A hosts.

CONCLUSION

Dead space management is an integral part of treating chronic osteomyelitis; however, no guidelines currently exist regarding the most appropriate strategy. Favourable results are achievable in low to middle-income countries, and it is evident that no dead space management strategy is superior to another. The pursuit for the ideal void filler is ongoing.

LEVEL OF EVIDENCE

III.

Trends and perspectives on the commercialization of bioactive glasses

At least 25 bioactive glass (BG) medical devices have been approved for clinical use by global regulatory agencies. Diverse applications include monolithic implants, bone void fillers, dentin hypersensitivity agents, wound dressing, and cancer therapeutics. The morphology and delivery systems of bioactive glasses have evolved dramatically since the first devices based on 45S5 Bioglass®. The particle size of these devices has generally decreased with the evolution of bioactive glass technology but primarily lies in the micron size range. Morphologies have progressed from glass monoliths to granules, putties, and cements, allowing medical professionals greater flexibility and control. Compositions of these commercial materials have primarily relied on silicate-based systems with varying concentrations of sodium, calcium, and phosphorus. Furthermore, therapeutic ions have been investigated and show promise for greater control of biological stimulation of genetic processes and increased bioactivity. Some commercial products have exploited the borate and phosphate-based compositions for soft tissue repair/regeneration. Mesoporous BGs also promise anticancer therapies due to their ability to deliver drugs in combination with radiotherapy, photothermal therapy, and magnetic hyperthermia. The objective of this article is to critically discuss all clinically approved bioactive glass products. Understanding essential regulatory standards and rules for production is presented through a review of the commercialization process. The future of bioactive glasses, their promising applications, and the challenges are outlined. STATEMENT OF SIGNIFICANCE: Bioactive glasses have evolved into a wide range of products used to treat various medical conditions. They are non-equilibrium, non-crystalline materials that have been designed to induce specific biological activity. They can bond to bone and soft tissues and contribute to their regeneration. They are promising in combating pathogens and malignancies by delivering drugs, inorganic therapeutic ions, and heat for magnetic-induced hyperthermia or laser-induced phototherapy. This review addresses each bioactive glass product approved by regulatory agencies for clinical use. A review of the commercialization process is also provided with insight into critical regulatory standards and guidelines for manufacturing. Finally, a critical evaluation of the future of bioactive glass development, applications, and challenges are discussed.

A scoping review of the outcome reporting following surgery for chronic osteomyelitis of the lower limb

Chronic osteomyelitis (COM) of the lower limb in adults can be surgically managed by either limb reconstruction or amputation. This scoping review aims to map the outcomes used in studies surgically managing COM in order to aid future development of a core outcome set. A total of 11 databases were searched. A subset of studies published between 1 October 2020 and 1 January 2011 from a larger review mapping research on limb reconstruction and limb amputation for the management of lower limb COM were eligible. All outcomes were extracted and recorded verbatim. Outcomes were grouped and categorized as per the revised Williamson and Clarke taxonomy. A total of 3,303 records were screened, of which 99 studies were included. Most studies were case series (77/99; 78%) and assessed one method of reconstruction (68/99; 69%). A total of 511 outcomes were reported, which were grouped into 58 distinct outcomes. Overall, 143/511 of all outcomes (28%) were provided with a clear, in-text definition, and 231 outcomes (45%) had details reported of how and when they were measured. The most commonly reported outcome was 'recurrence of osteomyelitis' (62; 12%). The single-most patient-reported outcome measure was 'pain'. This study has highlighted significant inconsistencies in the defining, reporting, and measuring of outcomes across studies investigating surgical management for chronic osteomyelitis of the lower limb in adults. Future studies should clearly report complete details of how outcomes are defined and measured, including timing. The development of a standardized core outcome set would be of significant benefit in order to allow evidence synthesis and comparison across studies.

Bioactive glass in the treatment of chronic osteomyelitis in children: Description of four consecutive cases and literature review

INTRODUCTION

Chronic osteomyelitis in children is a rare condition. Debridement surgery, along with appropriate antibiotic therapy, is widely agreed to represent the best procedure in the treatment of chronic osteomyelitis but can result in an extensive dead space formation. In this study, we evaluated the use of bioactive glass to address dead space management.

METHODS

Four consecutive cases of chronic osteomyelitis treated with antibiotic therapy, one stage- surgical debridement and bioglass implantation between September 2016 and February 2017 were prospectively followed for a minimum of three years. Two cases followed acute hematogenous osteomyelitis, two cases followed fracture fixation. Clinical, histology, laboratory and radiographic findings were recorded. Primary endpoint was eradication of infection. Possible complication related to bioglass application were investigated.

RESULTS

All patients achieved healing at the latest follow-up of minimum three years. No successive surgical treatments were required at any time. No complications related to the bioglass were detected. Radiographic reconstruction of normal anatomy progressed through the years.

CONCLUSIONS

Bioglass for the treatment of dead space after surgical debridement appears a viable option in the treatment of chronic osteomyelitis in children.

Evaluating physiological progression of chronic tibial osteomyelitis using infrared thermography

Purpose

Medical infrared thermography (IRT) was used as a complementary means for the clinical evaluation of musculoskeletal trauma and progression of chronic tibial osteomyelitis.

Methods

Twenty-two adult patients with a medical diagnosis of chronic tibial osteomyelitis were followed up by IRT performed along with standard radiography. Thermal data of the affected limb were compared with those of the healthy contralateral limb based on the thermal profile of the lower limbs as per the medical thermography guideline (32 °C). Data were acquired in the following regions of the lower limb: proximal tibia, diaphysis, and distal tibia, using a FLIR infrared camera, and data were processed using MATLAB®.

Results

For patients with active infections, an increase in the average temperature of the affected limb above + 1.0 °C was observed when compared with the temperature of the contralateral. The wound region of the patients showed an increased temperature (32.3 °C) compared with the temperature of the contralateral (31.4 °C). In contrast, in latent infections, the thermal differences were small, generally below 0.3 °C, and thus were within the threshold of normality. In contrast, in areas diagnosed with reduced blood supply, the affected limb showed an average temperature up to − 5.7 °C below normal. Additionally, the initial temperature range (26.5 to 34.5 °C) decreased during the treatment to 29.8 to 34.1 °C, indicating a convergence toward normality.

Conclusion

IRT has significant potential as a complementary imaging modality in the follow-up of patients with bone lesions with a diagnosis of osteomyelitis as it does not use ionizing radiation, thus allowing repetitive use as desired. Thermal images show important physiological information related to vascularization necessary for bone repair, as well as provide a good indication of the boundary of the infected area, adjacent to the trauma, which is useful for positioning the radiography equipment. However, it should be noted that IRT cannot replace other medical imaging techniques, as it provides information about the skin and cannot directly evaluate the interior of the body.

Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices

The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.

Mid-term clinical results of chronic cavitary long bone osteomyelitis treatment using S53P4 bioactive glass: a multi-center study

Introduction: Chronic osteomyelitis is a challenging condition in the orthopedic practice and traditionally treated using local and systemic antibiotics in a two-stage surgical procedure. With the introduction of the antimicrobial biomaterial S53P4 bioactive glass (Bonalive^®), chronic osteomyelitis can be treated in a one-stage procedure. This study evaluated the mid-term clinical results of patients treated with S53P4 bioactive glass for long bone chronic osteomyelitis. Methods: In this prospective multi-center study, patients from two different university medical centers in the Netherlands were included. One-stage treatment consisted of debridement surgery, implantation of S53P4 bioactive glass, and treatment with culture-based systemic antibiotics. If required, wound closure by a plastic surgeon was performed. The primary outcome was the eradication of infection, and a secondary statistical analysis was performed on probable risk factors for treatment failure. Results: In total, 78 patients with chronic cavitary long bone osteomyelitis were included. Follow-up was at least 12 months (mean 46; standard deviation, SD, 20), and 69 patients were treated in a one-stage procedure. Overall infection eradication was 85 %, and 1-year infection-free survival was 89 %. Primary closure versus local/muscular flap coverage is the only risk factor for treatment failure. Conclusion: With 85 % eradication of infection, S53P4 bioactive glass is an effective biomaterial in the treatment of chronic osteomyelitis in a one-stage procedure. A major risk factor for treatment failure is the necessity for local/free muscle flap coverage. These results confirm earlier published data, and together with the fundamentally different antimicrobial pathways without antibiotic resistance, S53P4 bioactive glass is a recommendable biomaterial for chronic osteomyelitis treatment and might be beneficial over other biomaterials.

Management of chronic osteomyelitis of the femur and tibia: a scoping review

Osteomyelitis refers to an inflammatory process causing bone destruction and necrosis. Managing such a persistent disease is complex, with a number of authors reporting different techniques. This scoping review aims to map and summarize the literature on treatment of chronic femoral and tibial osteomyelitis, in order to improve the reader's understanding of potential treatments and identify areas of further research.The methodological framework of the Joanna Briggs Institute was followed. A computer-based search was conducted in PubMed, EMBASE, MEDLINE, EMCARE and CINAHL, for articles reporting treatment of chronic tibial/femoral osteomyelitis. Two reviewers independently performed title/abstract and full-text screening according to pre-defined criteria.A total of 1230 articles were identified, with 40 finally included. A range of treatments are reported, with the core principles being removal of infected tissue, dead-space management and antibiotic therapy. The majority (84.5%) of patients presented with stage III or IV disease according to the Cierny-Mader classification, and Staphylococcus aureus was the most commonly isolated organism. The proportion of patients achieving remission with no recurrence during follow-up varies from 67.7-100.0%.The majority of studies report excellent outcomes in terms of infection remission and lack of recurrence. However, identifying specific patient or treatment-related factors which may affect outcomes is currently challenging due to the nature of the included studies and unclear reporting of treatment outcomes. It is now important to address this issue and identify such factors using further high-level research methods such as randomized controlled trials and comparative cohort studies. Cite this article: EFORT Open Rev 2021;6:704-715. DOI: 10.1302/2058-5241.6.200136.

Dissolution of Amorphous S53P4 Glass Scaffolds in Dynamic In Vitro Conditions

The silicate-based bioactive glass S53P4 is clinically used in bone regenerative applications in granule form. However, utilization of the glass in scaffold form has been limited by the high tendency of the glass to crystallize during sintering. Here, careful optimization of sintering parameters enabled the manufacture of porous amorphous S53P4 scaffolds with a strength high enough for surgical procedures in bone applications (5 MPa). Sintering was conducted in a laboratory furnace for times ranging from 25 to 300 min at 630 °C, i.e., narrowly below the commencement of the crystallization. The phase composition of the scaffolds was verified with XRD, and the ion release was tested in vitro and compared with granules in continuous flow of Tris buffer and simulated body fluid (SBF). The amorphous, porous S53P4 scaffolds present the possibility of using the glass composition in a wider range of applications.

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.

Structural and elemental characterization of glass and ceramic particles for bone surgery

OBJECTIVE

Clinically used bioceramics have been characterized previously with different kinds of methods and comparison of results have proven to be difficult due to varieties of the material properties of interest. Therefore, in this study we compared clinically commonly used bioceramics of hydroxyapatite and carbonate apatite, two bioactive glasses 45S5 and S53P4, and alumina with respect of properties which according to the present knowledge are significant for bone biology.

METHODS

Physicochemical properties of the materials were characterized by various methods. Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) was used to analyze the material vibrational features. X-ray Power Diffraction (XRD) was used to characterize the material crystal structure and scanning electron microscopy-energy-dispersive x-ray analysis (SEM-EDXA) was used to evaluate the morphology and size of the materials and to calculate their oxide content. The dissolution behavior of the materials, ion release and pH changes in Tris buffer in a continuous flow-through reaction for 24-hours were determined. The change of the surface of the bioactive glasses by interfacial reaction during the Tris immersion was examined and the thickness of the surface reaction layer of the materials was studied.

RESULTS

SEM examination showed that the particle morphology of BG 45S5, BG S53P4 and alumina particle's surface was smooth. The surface of HAP was porous, but also CAP showed some surface porosity. An increase in the pH of the immersion solution was observed especially for BG 45S5 and BG S53P4. HAP, CAP and alumina caused only a minor increase in pH. BGs 45S5 and S53P4 showed a rapid initial release of sodium and calcium ions, followed by the release of silicon species. Minor release of sodium ions was registered for HAP, CAP and alumina. Calcium ion release was low but constant over the experimental time while only a minor initial dissolution was measured for HAP.

SIGNIFICANCE

The in vitro study showed differences in the materials' properties, which are considered to be important for biological suitability and in clinical applications, such as materials tomography, ion release and pH changes.

Efficacy and Safety of Bioactive Glass S53P4 as a Treatment for Diabetic Foot Osteomyelitis

Osteomyelitis represents a challenging condition in the diabetic foot with an associated high risk of major amputation. S53P4 Bioactive Glass (BG) has bacterial inhibiting properties on the market and indicated to be used in osteomyelitis. The objective of the study was to test the efficacy and safety of BG in treating diabetic foot osteomyelitis. This was an observational, retrospective, single-centre study involving subjects with diabetes affected by osteomyelitis of the foot who underwent surgical debridement from 01/2016 to 10/2018. Overall, 44 diabetic patients (14 [31.8%] female, aged 68.0 ± 10.2 years, diabetes duration 26.8 ± 11.9 years) were studied: 22 (50%) treated with surgical debridement and a local application of BG; 22 (50%) treated by means of surgical debridement. The primary outcome was the osteomyelitis resolution. Revascularization was performed before surgical procedure in 31 (70.5%) of patients. Systemic antibiotics were used in both groups. The osteomyelitis resolution rate was significantly higher in subjects treated with BG than in subjects treated with traditional procedure (18 [90%] vs 13 [61.9%], respectively p = .03). The odds of BG to reach osteomyelitis resolution was 5.54 times greater than for traditional treatment (odds ratio 5.54, 95% confidence interval 1.10-30.5). The use of BG was associated with an 81% lower probability to need additional antibiotic therapy compared to subjects treated with traditional procedure (odds ratio 0.19, 95% confidence interval 0.04-0.87). The debridement of osteomyelitis followed by application of BG could be an effective and safe option in the treatment of osteomyelitis of the diabetic foot.

Collagen fleece in orthopaedic infections

Collagen fleece is a relatively new development. It represents another option in the battle against infection. It is a cheap, biocompatible, and resorbable local antibiotic delivery mechanism with favorable drug release kinetics and low risk of adverse effects or toxicity. Benefit may be conferred when used in contaminated cases. Significantly more research is still needed before the adoption of collagen fleece as the standard of care. However, we can likely conclude that there are no major adverse effects and it can be safely used as an adjunct in addition to conventional therapies for the prophylaxis and treatment of infections.

Treatment of infected tibial non-unions using a BMAC and S53P4 BAG combination for reconstruction of segmental bone defects: A clinical case series

INTRODUCTION

Treatment of infected non-unions of the tibia is a challenging problem. The cornerstones of optimal infected non-union treatment consist of extensive debridement, fracture fixation, antimicrobial therapy and creation of an optimal local biological bone healing environment. The combination of S53P4 bioactive glass (BAG), as osteostimulative antibacterial bone graft substitute, and bone marrow aspirate concentrate (BMAC) for the implantation of mesenchymal stem cells and growth factors might be a promising combination. In this paper, preliminary results of a new treatment algorithm for infected non-unions of the tibia is presented.

METHODS

In this retrospective case series patients with infected non-unions of the tibia are treated according to a new treatment algorithm. Patients are treated with extensive debridement surgery, replacement of the osteosynthesis and implantation of S53P4 BAG and BMAC in a one-stage or two-stage procedure based on non-union severity. Subsequently patients are treated with culture based antibiotic therapy and followed until union and infection eradication.

RESULTS

Five patients with an infected non-union were treated, mean age was 55, average NUSS-score was 44 and the average segmental bone defect was 4.6cm. One patient was treated in a one-stage procedure and four patients in a two-stage induced membrane-, or "Masquelet"-procedure. On average, 23 ml S53P4 BAG and 6.2 ml BMAC was implanted. The mean follow-up period was 13.6 months and at the end of follow-up all patients had clinical consolidation with an average RUST-score of 7.8 and complete eradication of infection.

DISCUSSION

These early data on the combined implantation of S53P4 BAG and BMAC in treatment of infected non-unions shows promising results. These fracture healing results and eradication rates resulted in promising functional recovery of the patients. To substantiate these results, larger and higher quality studies should be performed.

Biomechanical behavior of functionally graded S53P4 bioglass-zirconia dental implants: Experimental and finite element analyses

OBJECTIVES

The aim of this work was to evaluate the biomechanical behavior of one-piece zirconia implants with a functionally graded bioglass (BG) layer as compared to monolithic zirconia and BG-coated implants, using the finite element method (FEM).

METHODS

Zirconia disks were infiltrated with bioglass S53P4 and then morphologically inspected by scanning electron microscopy (SEM) followed by mechanical analyses on micro-indentation tests for further biomechanical validation using the finite element method (FEM). On modeling, zirconia dental implants anchored into mandibular bone were simulated on occlusal loading as recorded under mastication. Three types of implants were simulated: i) free of BG coating, ii) with 100 μm or 150 μm thick conventional BG coatings; and iii) with graded BG coatings involving 3 different chemical composition distributions. The stress state at both implant and bone were evaluated using the FEM. The mechanically-induced bone remodelling was analyzed through the bone strain results.

RESULTS

Infiltration of BG into a zirconia structure resulted in a ∼100 μm thick layer with an exponential-like gradation of chemical composition and properties. Regarding the FEM calculations, the BG coating induced up to 30% decrease on stress in the implant body when compared to the monolithic zirconia implant. The gradient of chemical composition also improved the stresses' distribution. The stresses distribution towards the BG-coatings were significantly high and could lead to failure. Stresses on the bone were recorded down to its strength threshold, with insignificant influence of the coating layer. The bone strain values on all models indicates further bone remodelling although BG-coated and BG-graded zirconia implants showed the highest strain magnitude that may enhance the mechanical stimulation for bone maintenance.

SIGNIFICANCE

Graded BG-zirconia dental implants showed enhanced overall biomechanical behaviour as compared to the BG-coated or monolithic zirconia dental implants. Also, such biomechanical improvements noticed for the BG-graded system should be considered in combination with the well-known osseointegration benefits of bioactive glasses.

Use of contemporary biomaterials in chronic osteomyelitis treatment: Clinical lessons learned and literature review

Chronic osteomyelitis has always been a therapeutic challenge for patient and surgeon due to the specific problems related with bone infection and bacterial biofilm eradication. Other than being the cause of infection or facilitating spread or persistence of infection, biomaterials are also becoming a tool in the treatment of infection. Certain novel biomaterials have unique and ideal properties that render them perfectly suited to combat infection and are therefore used more and more in the treatment of chronic bone infections. In case of infection treatment, there is still debate whether these properties should be focused on bone regeneration and/or their antimicrobial properties. These properties will be of even greater importance with the challenge of emerging antimicrobial resistance. This review highlights indications for use and specific material properties of some commonly used contemporary biomaterials for this indication as well as clinical experience and a literature overview.

Bioactive glass S53P4 vs. autologous bone graft for filling defects in patients with chronic osteomyelitis and infected non-unions - a single center experience

Introduction: The goals of osteomyelitis therapy are successful control of infection and reconstruction of the bone. The gold standard for filling defects is the autologous bone graft. Bioactive glass S53P4 is an inorganic bone substitute. We compared the outcome of using bioactive glass (BAG) versus autologous bone graft (AB) in patients with infected non-union. Methods: Patients with chronic osteomyelitis and infected non-union who received either bioactive glass or autologous bone grafts between 2013 and 2017 were analyzed retrospectively. The primary endpoint was successful control of infection during follow-up. Secondary endpoints were bone healing, functional outcome, and occurrence of complications. Results: Eighty-three patients were analyzed (BAG n=51, AB n=32). Twenty-one patients experienced reinfection (BAG n=15, 29 %; AB n=6, 19 %). Seventy-eight patients achieved full weight bearing (BAG n=47, 92 %; AB n=31, 97 %). Sixty-four patients had complete bone healing at the end of the follow-up period (BAG n=39, 77 %; AB n=25, 78 %). There were no significant differences between the groups with respect to the primary or secondary endpoints. Patients with multidrug-resistant pathogens had a significantly higher rate of incomplete bone healing (p=0.033) and a 3-fold higher risk of complications in both groups. Conclusions: Bioactive glass appears to be a suitable bone substitute not only for successful control of infection and defect filling but also for bone healing in cases of infected non-union. In our study, bioactive glass was neither superior nor inferior to autologous bone graft with regard to the primary and secondary endpoints. Further studies with larger numbers of patients are required.

Defensive antibacterial coating in revision total hip arthroplasty: new concept and early experience

BACKGROUND

Infections remains the most feared complication in total hip arthroplasty (THA). New strategies of PJI prevention includes coating of conventional implants. Defensive Antibacterial Coating (DAC), an antibacterial hydrogel coating made of hyaluronan, poly-D and L-lactide can protect biomaterials as an effective barrier at the time of implantation. In addition, it can be used with topical antibiotics to prevent early colonisation of the implant.

SCOPE

This manuscript describes the detailed function of the DAC in general as well as an analysis of its use in revision THA in a series of 28 patients in a short-term follow-up.Its use in patients undergoing cementless re-implantation after 2-staged procedures in THA is described in detail within the manuscript.

CONCLUSION

DAC found to be effective in terms of infection control and safety in our patient cohort and has been expanded for cementless 1-staged revisions in PJI of the hip in our institution.

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

The one-stage treatment of chronic osteomyelitis with S53P4 bioactive glass (BAG) granules has shown excellent results. However, these granules possess suboptimal handling properties. Therefore, new injectable S53P4 putty materials have been developed by the incorporation of a synthetic binder to contain glass granules. The goal of the current study was to assess their potential to eradicate five clinically relevant pathogens: methicillin sensitive Staphylococcus aureus (MSSA), methicillin resistant Staphylococcus aureus (MRSA), Enterococcus coli (E. coli), Enterococcus faecalis (E. faecalis), and Pseudomonas aeruginosa (P. aeruginosa). As a control, S53P4 granules (500–800 μm) and S66 glass (< 45 μm) were used. To evaluate the antimicrobial properties, the materials were cultured with the pathogens in a Müller-Hinton II broth for a week with daily colony forming unit (CFU) counting. One of the tested putty formulations was observed to reduce the number of CFU/mL compared to a negative control (no material, only pathogen in broth) for E. coli, E. faecalis and P. aeruginosa. However, none of the tested putty formulations was able to completely eradicate the pathogens in the broths, which would be needed for safe infection treatment. The results obtained for the control materials were unexpected. S66 glass showed full eradication of P. aeruginosa and reduced the number of CFUs of other pathogens, while the S53P4 granules did not show eradication. The observations on the loose S53P4 granules in this study contradict available literature, which needs further investigation. The results obtained in this study also stretch the importance for a better understanding of the underlying antimicrobial mechanism of S53P4 BAG and how this is related to the dosage. In addition, it should be elucidated how these antimicrobial properties are affected by changes in the material formulation, for example by addition of binders to improve the handling properties or by changing the surface area.

Treatment of Infected Tibial Non-Unions with Ilizarov Technique: A Case Series

Background: The Ilizarov external fixation technique has been widely used for the treatment of long-bone infected non-unions. After surgical infected bone resection, to allow filling of the remaining bone gap, biomaterials with antibacterial properties could be used. The aim of this study was to report outcomes of infected tibial non-unions treated using the Ilizarov technique and antibacterial bioactive glass. Methods: Between April 2009 and December 2014, 26 patients with infected tibial non-unions were treated with the Ilizarov technique and possible use of the bioactive glass, S53P4. The Association for the Study and Application of Methods of Ilizarov (ASAMI) criteria, a clinical and radiographic evaluating tool, was used for assessing the sample. Results: The average age at the start of treatment was 51 years. The mean follow-up time was 113 weeks. According to the ASAMI Functional Scoring System, 10 excellent (38.5%) cases and 12 good (46.1%) values were recorded. According to the ASAMI Radiological System, they were excellent in 16 (61.5%) cases and good in nine (34.6%). Conclusions: Treatment of infected tibial non-unions using the Ilizarov technique was effective in bone segment regeneration. To fill the remaining bone gap, additional bioactive glass S53P4 could be used, allowing a decrease in re-interventions and minimizing complications.

Treatment of Infected Tibial Non-Unions with Ilizarov Technique: A Case Series

Background: The Ilizarov external fixation technique has been widely used for the treatment of long-bone infected non-unions. After surgical infected bone resection, to allow filling of the remaining bone gap, biomaterials with antibacterial properties could be used. The aim of this study was to report outcomes of infected tibial non-unions treated using the Ilizarov technique and antibacterial bioactive glass. Methods: Between April 2009 and December 2014, 26 patients with infected tibial non-unions were treated with the Ilizarov technique and possible use of the bioactive glass, S53P4. The Association for the Study and Application of Methods of Ilizarov (ASAMI) criteria, a clinical and radiographic evaluating tool, was used for assessing the sample. Results: The average age at the start of treatment was 51 years. The mean follow-up time was 113 weeks. According to the ASAMI Functional Scoring System, 10 excellent (38.5%) cases and 12 good (46.1%) values were recorded. According to the ASAMI Radiological System, they were excellent in 16 (61.5%) cases and good in nine (34.6%). Conclusions: Treatment of infected tibial non-unions using the Ilizarov technique was effective in bone segment regeneration. To fill the remaining bone gap, additional bioactive glass S53P4 could be used, allowing a decrease in re-interventions and minimizing complications.

The effect of bioactive glasses on spinal fusion: A cross-disciplinary systematic review and meta-analysis of the preclinical and clinical data

Pseudarthrosis following spinal fusion is correlated with poorer patient outcomes and consequently is an area of continued interest within spinal research. Recently, bioactive glasses have been proposed as a means of augmenting fusion rates. Here, we present the first systematic review and meta-analysis of the existing preclinical and clinical literature on the effect of bioactive glasses on spinal fusion. Using the MEDLINE, Embase, and Web of Science databases, we queried all publications in the English-language literature examining the effect of bioactive glasses on spinal fusion. The primary endpoint was fusion rate at last follow-up and the secondary endpoint for clinical studies was the rate of deep wound infection. Random-effects meta-analyses were performed independently for the preclinical and clinical data. Twelve preclinical studies (267 animals) and 12 clinical studies (396 patients) evaluating a total of twelve unique bioactive glass formulations were included. Across clinical studies, fusion was seen in 84% treated with bioactive glass. On sub-analysis, fusion rates were similar for standalone autograft (91.6%) and bioactive glass-local autograft mixtures (89.6%). Standalone bioactive glass substrates produced inferior fusion rates relative to autograft alone (33.6% vs. 98.8%; OR 0.01, p < 0.02). Rates of deep wound infection did not differ between the bioactive glass and autograft groups (3.1%). The preclinical data similarly showed comparable rates of fusion between autograft and bioactive glass-treated animals. The available data suggest that bioactive glass-autograft mixtures confer similar rates of spinal fusion relative to standalone autograft without altering the risk of deep wound infection.

Developments in Antibiotic-Eluting Scaffolds for the Treatment of Osteomyelitis

Osteomyelitis is a devastating disease caused by the infection of bone tissue and is associated with significant morbidity and mortality. It is treated with antibiotic therapy and surgical debridement. A high dose of systemic antibiotics is often required due to poor bone penetration and this is often associated with unacceptable side-effects. To overcome this, local, implantable antibiotic carriers such as polymethyl methacrylate have been developed. However, this is a non-biodegradable material that requires a second surgery to be removed. Attention has therefore shifted to new antibiotic-eluting scaffolds which can be created with a range of unique properties. The purpose of this review is to assess the level of evidence that exists for these novel local treatments. Although this field is still developing, these strategies seem promising and provide hope for the future treatment of chronic osteomyelitis.

Bioactive glass as dead space management following debridement of type 3 chronic osteomyelitis

BACKGROUND

Chronic osteomyelitis is a challenging condition to treat and although no exact treatment guidelines exist, the surgical management strategy includes wide resection of necrotic and infected bone followed by dead space management. This study evaluates the use of bioactive glass as a single-stage procedure for dead space management following surgical debridement.

METHODS

A consecutive series of 24 patients with Cierny-Mader type 3 osteomyelitis, treated between March 2016 and June 2018, were identified and evaluated retrospectively. Patients were managed with bioactive glass as dead space management following surgical debridement.

RESULTS

Of the patients who completed more than 12 months follow-up, all fourteen (100%) showed complete resolution of symptoms. Of the remaining ten patients with less than 12 months follow-up, eight had complete resolution of symptoms. Therefore, a preliminary result of 22 out of 24 patients (91.65%) had resolution of symptoms following debridement and dead space management with bioactive glass. One patient experienced a complication related to the use of bioactive glass. This manifested as prolonged serous wound drainage that resolved with local wound care.

CONCLUSION

The use of bioactive glass appears to be effective for dead space management following debridement of anatomical type 3 chronic osteomyelitis of the appendicular skeleton.

Antimicrobial activity of bioactive glass S53P4 against representative microorganisms causing osteomyelitis - Real-time assessment by isothermal microcalorimetry

Bioactive glass (BAG) is a synthetic bone substitute with intrinsic antimicrobial properties, used for bone defect filling. We evaluated the antimicrobial activity of two formulations of BAG S53P4 against representative pathogens of osteomyelitis: Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli and Candida albicans. Antimicrobial activity of BAG S53P4 was assessed by isothermal microcalorimetry, a highly sensitive assay measuring metabolic-related microbial heat production in real-time. Standard CFUs-counting was performed in parallel. BAG granules (diameter 500-800 μm) and powder (<45 μm) were evaluated in two concentrations (400 and 800 mg/ml). Isothermal microcalorimetry was performed in glass ampoules containing growth medium, BAG and test microorganism, heat production was measured for 24 h. BAG S53P4 inhibited heat production of most-tested microorganisms with heat reduction of 60%-98% compared to positive control after 24 h of exposure to the highest-tested concentration (800 mg/ml). BAG S53P4 in powder formulation (<45 μm) inhibited more microbial growth than in granule formulation (500-800 μm), with the exception of C. albicans for which both formulations presented similar inhibition rates ranging between 87 % and 97 %. The BAG inhibitory ratios estimated from the variation in the growth rate constants of each microorganism compared to the growth control ranged between 2.55 % and 100 %. Comparable results were obtained by CFUs-counting, with complete reduction in cell viability of most microorganisms after ≤ 24 h of microbial exposure to BAG S53P4 powder. In summary, BAG S53P4 demonstrated efficient inhibition of microbial growth, especially in powder formulation.

Evidence-Based Recommendations for Local Antimicrobial Strategies and Dead Space Management in Fracture-Related Infection

Fracture-related infection (FRI) remains a challenging complication that imposes a heavy burden on orthopaedic trauma patients. The surgical management eradicates the local infectious focus and if necessary facilitates bone healing. Treatment success is associated with debridement of all dead and poorly vascularized tissue. However, debridement is often associated with the formation of a dead space, which provides an ideal environment for bacteria and is a potential site for recurrent infection. Dead space management is therefore of critical importance. For this reason, the use of locally delivered antimicrobials has gained attention not only for local antimicrobial activity but also for dead space management. Local antimicrobial therapy has been widely studied in periprosthetic joint infection, without addressing the specific problems of FRI. Furthermore, the literature presents a wide array of methods and guidelines with respect to the use of local antimicrobials. The present review describes the scientific evidence related to dead space management with a focus on the currently available local antimicrobial strategies in the management of FRI. LEVEL OF EVIDENCE:: Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

The use of bioactive glass S53P4 in the treatment of an infected Charcot foot: a case report

OBJECTIVE:

To report a case of successful limb-salvage staged treatment in the treatment of an infected diabetic Charcot foot.

CASE SUMMARY:

A 45-year-old male with long-term, uncontrolled type 2 diabetes, six months' history of progressive deformity on the right foot and 45 days of purulent drainage in the lateral aspect of the foot. Patient was diagnosed with an infected Charcot foot with extensive midfoot bone involvement as shown by radiographic and MRI images. We used a multidisciplinary approach to treatment with early antibiotic therapy, tight glycaemic control and staged surgical treatment. Initial treatment was adequate irrigation and debridement, bone-void filling with bioactive glass, external fixation and provisional negative pressure wound therapy (NPWT). Later progressed to total contact casting and progressive protect weight bearing. At final follow-up, patient was full weight-bearing in stiff soled footwear, with no clinical signs of infection, no gross alteration of gait pattern and demonstrating complete bone healing and integration of the bioactive glass.

CONCLUSION:

The bioactive glass S53P4 was successfully used in the limb-salvage staged treatment of a patient with an infected Charcot foot. Here, full integration with the surrounding bone and its supportive action in the combat of bone infection was demonstrated.

The role of bioactive glass in the management of chronic osteomyelitis: a systematic review of literature and current evidence

Background: The increase of orthopaedic surgical interventions has given rise to an increased prevalence of chronic osteomyelitis. The principles of management of chronic osteomyelitis are well defined and include a thorough debridement, dead space management followed by an adequate period of appropriate antibiotics. Bioactive glass has garnered interest in recent years as a potential void filler following debridement. In the present systematic review, we explore the role of bioactive glass as a dead space management agent following debridement of chronic osteomyelitis.Methods: A search was made for all the articles pertaining to the role of bioactive glass in chronic osteomyelitis. The keywords used for search in PUBMED/MEDLINE were 'Bioactive glass' and 'chronic osteomyelitis'. A total of nine publications evaluating the outcome of 206 patients were included for evaluation.Results: The overall cure rate was 86% with 24 patients (11.6%) experiencing recurrence, while five patients were lost to follow-up. Out of the total 24 recurrences or persistent infections, 10 were associated with poor post-operative wound healing which progressed to recurrence.Conclusions: Bioactive glass appears to provide an attractive alternative for bone void filling after debridement of chronic osteomyelitis with good long-term outcomes. Potential advantages include a unique mechanism of anti-microbial action rendering it active against multi-drug resistant bacteria, use as a single stage procedure and gradual replacement by bone.

The Implantation of Bioactive Glass Granules Can Contribute the Load-Bearing Capacity of Bones Weakened by Large Cortical Defects

Bioactive glass (BAG) granules (S53P4) have shown good clinical results in one-stage treatment of osteomyelitis. During this treatment, a cortical window is created, and infected bone is debrided, which results in large defects that affect the mechanical properties of the bone. This study aimed to evaluate the role of BAG granules in load-bearing bone defect grafting. First, the influence of the geometry of the cortical window on the bone bending stiffness and estimated failure moments was evaluated using micro finite element analysis (µFE). This resulted in significant differences between the variations in width and length. In addition, µFE analysis showed that BAG granules contribute to bearing loads in simulated compression of a tibia with a defect grafted with BAG and a BAG and bone morsel mixture. These mixtures potentially can unload the cortical bone that is weakened by a large defect directly after the operation by up to approximately 25%, but only in case of optimal load transfer through the mixture.

Structural performance of poultry eggshell derived hydroxyapatite based high density polyethylene bio-composites

In this research, hydroxyapatite (HAp) was synthesized from chicken eggshell waste by hydrothermal method for the development of bio-composite material suitable for biomedical implant. However, since environmental influences on natural materials are unique for different geographical locations in the world, the use of agro wastes from these locations need to be investigated. This work provides the detail results of the potentials of eggshell as HAp source. High-density polyethylene (HDPE)/HAp composites were developed by random dispersion of Hap (10, 20, 30 and 40 wt.%) in HDPE matrix, and were designated as HAC10, HAC20, HAC30, and HAC40. The HAp-filled HDPE composites were developed by a hot compression moulding process. The samples were subjected to tensile, flexural, impact, fracture toughness and wear tests according to ASTM standards in order to establish their structural performance as an implant material. Furthermore, the samples were also tested for hydrophilicity using tap water and simulated body fluid (SBF). X-ray diffraction analysis showed strong peaks of hydroxyapatite phase which established that the influence of the selected processing conditions on the poultry eggshell as a natural source for the biomedical application was suitable for the synthesis of high-quality hydroxyapatite. The mechanical properties of the developed composites were enhanced to the level of the required properties expected of an implant material compared to the control sample except for impact strength. Water absorption characteristics of the developed composite samples also displayed expected behaviour in SBF solution than in tap water thereby promoting the material as a good implant material. From the results, the sample with 40 wt.% HAp possess the highest values in the mechanical properties examined while sample from 20 wt.% had the best fracture toughness. The results revealed that these waste eggshells could be successfully converted into useful biocompatible HAp particles needed for the enhancement of the mechanical properties of polymer composites to meet the structural challenges of bio-composites.

Bilateral tibial Brodie's abscess in a young patient treated with BAG-S53P4: case report

Background

Brodie’s abscess is a form of chronic pyogenic osteomyelitis that usually affects the cancellous part of the long bones in children. Its treatment is represented by antibiotic therapy alone or in association with surgical procedures.

Case presentation

A 12-years-old male affected by a Brodie’s abscess of the tibia involving the distal growth plate was admitted to the Pediatric Department for a conservative treatment. After several attempts of antibiotic therapy interrupted for intolerance manifestations he was surgically treated with bioactive glass BAG-S53P4 (BonAlive, BonAlive Biomaterials Ltd., Biolinja, Finland), with excellent results.

Conclusions

In our experience BAG-S53P4 has proven to be an effective bone substitute without side effects even in the pediatric population. In our case it eradicated the infection without interfere with the growth; neither epiphysiodesis nor other disorders were found during the follow-up.

For the publication of this case report we followed the CARE guidelines for good clinical case reports; the parents gave consent for publication.

Antibiotic-Loaded Polymethylmethacrylate Beads and Spacers in Treatment of Orthopedic Infections and the Role of Biofilm Formation

Polymethylmethacrylate (PMMA) also referred as (acrylic) bone cement is a non-degradable biomaterial that has been used in clinical orthopedic practice for several decades. PMMA can be used in a plain formulation, but is often used in an antibiotic-loaded formulation in (primary and revision) arthroplasty and in treatment of orthopedic infections as prosthetic joint infections (PJI) and chronic osteomyelitis. In treatment of PJIs antibiotic-loaded PMMA is often used as a carrier material for local antibiotic delivery in addition to treatment with systemic antibiotics. In this case, the antibiotic-loaded PMMA is often used as a spacer or as a bead chain. Since the introduction of PMMA as an antibiotic carrier there is a tremendous amount of scientific and clinical papers published, which studied numerous different aspects of antibiotic-loaded PMMA. This paper will review the research regarding basic principles of antibiotic-loaded PMMA as mechanism of action, antibiotic-release capacities, choice of antibiotics and influences on mechanical properties of PMMA. Subsequently, concerns regarding the application of antibiotic-loaded PMMA, biofilm formation, antibiotic resistance and local or systemic toxicity will be discussed. In addition to these subjects, the role of antibiotic loaded PMMA in clinical treatment of PJIs and chronic osteomyelitis is discussed in the final part of this paper.

Diagnosis of peripheral bone and prosthetic joint infections: overview on the consensus documents by the EANM, EBJIS, and ESR (with ESCMID endorsement)

OBJECTIVES

Peripheral bone infection (PBI) and prosthetic joint infection (PJI) are two different infectious conditions of the musculoskeletal system. They have in common to be quite challenging to be diagnosed and no clear diagnostic flowchart has been established. Thus, a conjoined initiative on these two topics has been initiated by the European Society of Radiology (ESR), the European Association of Nuclear Medicine (EANM), the European Bone and Joint Infection Society (EBJIS), and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID). The purpose of this work is to provide an overview on the two consensus documents on PBI and PJI that originated by the conjoined work of the ESR, EANM, and EBJIS (with ESCMID endorsement).

METHODS AND RESULTS

After literature search, a list of 18 statements for PBI and 25 statements for PJI were drafted in consensus on the most debated diagnostic challenges on these two topics, with emphasis on imaging.

CONCLUSIONS

Overall, white blood cell scintigraphy and magnetic resonance imaging have individually demonstrated the highest diagnostic performance over other imaging modalities for the diagnosis of PBI and PJI. However, the choice of which advanced diagnostic modality to use first depends on several factors, such as the benefit for the patient, local experience of imaging specialists, costs, and availability. Since robust, comparative studies among most tests do not exist, the proposed flowcharts are based not only on existing literature but also on the opinion of multiple experts involved on these topics.

KEY POINTS

• For peripheral bone infection and prosthetic joint infection, white blood cell and magnetic resonance imaging have individually demonstrated the highest diagnostic performance over other imaging modalities. • Two evidence- and expert-based diagnostic flowcharts involving variable combination of laboratory tests, biopsy methods, and radiological and nuclear medicine imaging modalities are proposed by a multi-society expert panel. • Clinical application of these flowcharts depends on several factors, such as the benefit for the patient, local experience, costs, and availability.

Optimized Bioactive Glass: the Quest for the Bony Graft

Technological advances have provided surgeons with a wide range of biomaterials. Yet improvements are still to be made, especially for large bone defect treatment. Biomaterial scaffolds represent a promising alternative to autologous bone grafts but in spite of the numerous studies carried out on this subject, no biomaterial scaffold is yet completely satisfying. Bioactive glass (BAG) presents many qualifying characteristics but they are brittle and their combination with a plastic polymer appears essential to overcome this drawback. Recent advances have allowed the synthesis of organic-inorganic hybrid scaffolds combining the osteogenic properties of BAG and the plastic characteristics of polymers. Such biomaterials can now be obtained at room temperature allowing organic doping of the glass/polymer network for a homogeneous delivery of the doping agent. Despite these new avenues, further studies are required to highlight the biological properties of these materials and particularly their behavior once implanted in vivo. This review focuses on BAG with a particular interest in their combination with polymers to form organic-inorganic hybrids for the design of innovative graft strategies.

Collagen scaffolds functionalised with copper-eluting bioactive glass reduce infection and enhance osteogenesis and angiogenesis both in vitro and in vivo

The bone infection osteomyelitis (typically by Staphylococcus aureus) usually requires a multistep procedure of surgical debridement, long-term systemic high-dose antibiotics, and - for larger defects - bone grafting. This, combined with the alarming rise in antibiotic resistance, necessitates development of alternative approaches. Herein, we describe a one-step treatment for osteomyelitis that combines local, controlled release of non-antibiotic antibacterials with a regenerative collagen-based scaffold. To maximise efficacy, we utilised bioactive glass, an established osteoconductive material with immense capacity for bone repair, as a delivery platform for copper ions (proven antibacterial, angiogenic, and osteogenic properties). Multifunctional collagen-copper-doped bioactive glass scaffolds (CuBG-CS) were fabricated with favourable microarchitectural and mechanical properties (up to 1.9-fold increase in compressive modulus over CS) within the ideal range for bone tissue engineering. Scaffolds demonstrated antibacterial activity against Staphylococcus aureus (up to 66% inhibition) whilst also enhancing osteogenesis (up to 3.6-fold increase in calcium deposition) and angiogenesis in vitro. Most significantly, when assessed in a chick embryo in vivo model, CuBG-CS not only demonstrated biocompatibility, but also a significant angiogenic and osteogenic response, consistent with in vitro studies. Collectively, these results indicate that the CuBG-CS developed here show potential as a one-step osteomyelitis treatment: reducing infection, whilst enhancing bone healing.

Antibiotic-Loaded Collagen Sponges in Clinical Treatment of Chronic Osteomyelitis: A Systematic Review

BACKGROUND

Chronic osteomyelitis is caused by bacterial infection of the bone and is a major problem in orthopaedic surgery. Treatment of chronic osteomyelitis requires surgical debridement accompanied by local and systemic administration of antibiotics. A widely established biodegradable local antibiotic carrier is antibiotic-loaded collagen sponges (fleeces). These sponges are commonly used in the treatment of chronic osteomyelitis, but a systematic review of their clinical efficacy and assessment of the quality of evidence have not been conducted, to our knowledge.

METHODS

This systematic review, performed according to the PRISMA statement, examined the clinical efficacy of and quality of evidence regarding different antibiotic-loaded collagen sponges in the clinical treatment of chronic osteomyelitis. Clinical efficacy was defined as eradication of infection with bone and wound-healing. In addition, the in vivo pharmacokinetics of the various collagen sponges were evaluated. Quality was based on the Level of Evidence, methodological quality, and risks of bias.

RESULTS

A total of 813 articles were screened, and 10 were included. Gentamicin-sulfate sponges and gentamicin-sulfate/gentamicin-crobefate sponges were studied. A total of 413 patients were treated, with a success rate of 91%. Reported complications were fistulas, prolonged wound drainage, and wound-healing problems. In vivo pharmacokinetic profiles showed an average local antibiotic concentration that was above the minimum inhibitory concentration for only 5 days. The general quality of the included studies was low to moderate, and there was a moderate to high risk of bias.

CONCLUSIONS

The evidence quality and Level of Evidence of the included studies were low, and the risk of bias in these studies was high. This makes the evidence regarding these sponges inconclusive, and no clinical decision-making can be based on these studies. Utilization of antibiotic-loaded collagen sponges in the treatment of chronic osteomyelitis should only be carried out with caution; studies with high-level evidence are needed.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Dentin pretreatment with 45S5 and niobophosphate bioactive glass: Effects on pH, antibacterial, mechanical properties of the interface and microtensile bond strength

OBJECTIVES

The aim of the study was to evaluate the effect of bioactive glass (45S5 and NbG) suspensions on bond strength (µTBS), hardness, modulus of elasticity, pH and antibacterial activity of the resin-dentin interfaces after 3 months.

METHODS

Groups with different concentrations (5% and 20%) of two types of glass (45S5 and NbG), and a control group (distilled water) were studied. Twenty-five extracted human third molars were etched with phosphoric acid. The data from µTBS, hardness and modulus of elasticity data were submitted to two-way ANOVA (suspension vs. time) and Holm-Sidak tests (=0.05). The antimicrobial activity data were analyzed by the Kruskal-Wallis test (α = 5%).

RESULTS

The interactions were significant among groups for µTBS (p = 0.033). Significant reductions in µTBS were observed after 3 months storage in PBS for the Control and 5% NbG Groups. Suspensions with 5% and 20% 45S5 glass and 20% NbG resulted in stable µTBS values and increased hardness after 3 months. Both 20% suspensions (45S5 and NbG) increased the elastic modulus. A significant greater reduction in bacterial growth was observed with the use of 20% 45S5.

CONCLUSION

Rewetting dentin with the suspension of 20% 45S5 glass prevented the reduction in bond strength; increased hardness; modulus of elasticity of the resin-dentin interface, and demonstrated antibacterial activity against Streptococcus mutans.

Daptomycin-loaded biodegradable thermosensitive hydrogels enhance drug stability and foster bactericidal activity against Staphylococcus aureus

A drug delivery system based on fully biodegradable thermosensitive hydrogels enabling controlled antibiotic release may support the management of implant-associated infections. In this work, the lipopeptide antibiotic daptomycin was encapsulated in hydrogel networks consisting of vinyl sulfonated triblock copolymers of PEG-p(HPMAm-lac_1,2) and thiolated hyaluronic acid. High concentrations of active daptomycin exceeding the minimum biofilm eradicating concentration were sustainably eluted from the biodegradable carrier. The drug release profiles were tailored by varying the degree of substitution (DS) of thiol groups of hyaluronic acid, reaching a plateau level after 200 and 330 h for DS values of 53% and 31%, respectively. The hydrogel polymeric network preserved the structural stability of the loaded antibiotic and retained the calcium-dependent daptomycin activity, showing a noticeable biofilm bactericidal effect against a 24 h-old Staphylococcus aureus biofilm in vitro. The two-component thermosensitive hydrogels demonstrated to be an excellent antibiotic releasing scaffold with potential clinical applications in the management of implant-associated infections.

An overview of development and status of fiber-reinforced composites as dental and medical biomaterials

Fibr-reinforced composites (FRC) have been used successfully for decades in many fields of science and engineering applications. Benefits of FRCs relate to physical properties of FRCs and versatile production methods, which can be utilized. Conventional hand lamination of prefabricated FRC prepregs is utilized still most commonly in fabrication of dental FRC devices but CAD-CAM systems are to be come for use in certain production steps of dental constructions and medical FRC implants. Although metals, ceramics and particulate filler resin composites have successfully been used as dental and medical biomaterials for decades, devices made out of these materials do not meet all clinical requirements. Only little attention has been paid to FRCs as dental materials and majority of the research in dental field has been focusing on particulate filler resin composites and in medical biomaterial research to biodegradable polymers. This is paradoxical because FRCs can potentially resolve many of the problems related to traditional isotropic dental and medical materials. This overview reviews the rationale and status of using biostable glass FRC in applications from restorative and prosthetic dentistry to cranial surgery. The overview highlights also the critical material based factors and clinical requirement for the succesfull use of FRCs in dental reconstructions.

In vitro antibacterial activity of bioactive glass S53P4 on multiresistant pathogens causing osteomyelitis and prosthetic joint infection

Background

Conventional local treatment for medullary osteomyelitis (OM) includes insertion of antibiotic-loaded polymethylmethacrylate (PMMA) cement. Nevertheless, PMMA may delivery irregular concentration of antibiotic to surrounding tissue. We aimed to compare the in vitro antibacterial activity of Bioactive Glass (BAG) S53P4, which is a compound showing local antibacterial activity, to that of antibiotic-loaded PMMA against multidrug resistant bacteria from OM isolates.

Methods

We studied convenience samples of multidrug resistant (MDR) microorganisms obtained from patients presenting OM and prosthetic joint infection (PJI). Mixtures containing tryptic soy broth (TSB) and inert glass beads (2 mm), BAG-S53P4 granules (0.5–0.8 mm and < 45 mm) and Gentamicin or Vancomycin-loaded PMMA beads were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus (MR-CoNS), Pseudomonas aeruginosa or Klebsiella pneumoniae isolates. Glass beads (2.0 mm) were used as a control. Antibacterial activity was evaluated by means of time-kill curve, through seeding the strains on blood agar plates, and subsequently performing colony counts after 24, 48, 72, 96, 120 and 168 h of incubation. Differences between groups were evaluated by means of two-way analysis of variance (ANOVA) and Bonferroni’s t test.

Results

Inhibition of bacterial growth started soon after 48 h of incubation, reached zero CFU/ml between 120 and 168 h of incubation for both antibiotic-loaded PMMA and BAG S53P4 groups, in comparison with inert glass (p < 0.05). No difference regarding time-kill curves between antibiotic-loaded PMMA and BAG S53P4 was observed.

Conclusions

BAG S53P4 presented antibacterial properties as much as antibiotic-loaded PMMA for MDR bacteria producing OM and PJI.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3069-x) contains supplementary material, which is available to authorized users.