A meta-analysis of bone cement mediated antibiotic release: Overkill, but a viable approach to eradicate osteomyelitis and other infections tied to open procedures

An Antibacterial-Loaded PLA 3D-Printed Model for Temporary Prosthesis in Arthroplasty Infections: Evaluation of the Impact of Layer Thickness on the Mechanical Strength of a Construct and Drug Release

Infections are one of the main complications in arthroplasties. These infections are difficult to treat because the bacteria responsible for them settle in the prosthesis and form a biofilm that does not allow antimicrobials to reach the infected area. This study is part of a research project aimed at developing 3D-printed spacers (temporary prostheses) capable of incorporating antibacterials for the personalized treatment of arthroplasty infections. The main objective of this research was to analyze the impact of the layer thickness of 3D-printed constructs based on polylactic acid (PLA) for improved treatment of infections in arthroplasty. The focus is on the following parameters: resistance, morphology, drug release, and the effect of antibacterials incorporated in the printed temporary prostheses. The resistance studies revealed that the design and layer thickness of a printed spacer have an influence on its resistance properties. The thickness of the layer used in printing affects the amount of methylene blue (used as a model drug) that is released. Increasing layer thickness leads to a greater release of the drug from the spacer, probably as a result of higher porosity. To evaluate antibacterial release, cloxacillin and vancomycin were incorporated into the constructs. When incorporated into the 3D construct, both antibacterials were released, as evidenced by the growth inhibition of Staphylococcus aureus. In conclusion, preliminary results indicate that the layer thickness during the three-dimensional (3D) printing process of the spacer plays a significant role in drug release.

Does the Addition of Low-Dose Antibiotics Compromise the Mechanical Properties of Polymethylmethacrylate (PMMA)?

The increasing numbers of total joint replacements and related implant-associated infections demand solutions, which can provide a high-dose local delivery of antibiotics. Antibiotic-loaded bone cement (ALBC) is an accepted treatment method for infected joint arthroplasties. The mechanical properties of low-dose gentamicin-loaded bone cement (BC) in medium- and high-viscosity versions were compared to unloaded BC using a vacuum mixing system. As an additional control group, manual mixed unloaded BC was used. In a uniaxial compression test, ultimate compressive strength, compressive yield strength, and compression modulus of elasticity, as well as ultimate and yield strain, were determined according to ISO 5833-2022 guidelines. All groups exceeded the minimum compressive strength (70 MPa) specified in the ISO 5833 guidelines. Both ALBC groups showed a similar ultimate compressive and yield strength to the unloaded BC. The results showed that vacuum mixing increased the compression strength of BC. ALBC showed similar compressive strength to their non-antibiotic counterparts when vacuum mixing was performed. Added low-dose gentamicin acted as a plasticizer on bone cement. From a biomechanical point of view, the usage of gentamicin-based ALBC formulations is viable.

High-dose vancomycin spacers provided early recovery without nephrotoxicity compared with standard-dose in MRSA-induced periprosthetic joint infection model of rats

BACKGROUND

Periprosthetic joint infections (PJIs) are commonly treated with two-stage revision surgery utilising antibiotic-loaded spacers; however, antibiotic release from spacers is limited and usually drops below effective levels a few days after placement. This study compared high-dose and standard-dose vancomycin-loaded spacers in terms of efficacy, safety, and overall treatment duration in a rat periprosthetic joint infection model.

METHODS

Thirty male Wistar albino rats (8-10 weeks old, 300-320 g) were housed individually at standard conditions. A periprosthetic infection model was established in the right knee of the rats using methicillin-resistant Staphylococcus aureus (MRSA) -contaminated Kirschner wires. Two weeks later, the infection was verified, and the Kirschner wires were removed. Rats were randomly divided into three groups (n = 10): standard-dose (SVanc) and high-dose (HVanc) vancomycin groups had 2.5 and 7.5% vancomycin in their spacers, respectively, while the control group had no spacers. All groups received intramuscular (IM) vancomycin and gentamicin for 4 weeks after spacer implantation. Microbiological counts and vancomycin levels in the blood and joint flush samples were measured, and histopathological assessments were conducted on the femur and kidneys.

RESULTS

After spacer implantation, MRSA was eliminated in the HVanc group with 4 weeks of treatment, while the SVanc group required 6 weeks of treatment (P < 0.001). Histopathological findings of the femoral medulla and cortical samples were better in the HVanc group compared with other groups (P = 0.007). Vancomycin levels in serum remained within safe limits in all groups, and kidney damage was not observed.

CONCLUSION

The use of high-dose vancomycin spacers might accelerate the transition period, which in turn reduces the duration of systemic antibiotic use and mitigates the risk of nephrotoxicity. Thus, this method may decrease the medical costs associated with PJI treatment.

Use of a Porous Alumina Antibiotic-Loaded Ceramic to Treat Bone Defect and Bone Infection After Road Trauma

To describe the use of a porous alumina ceramic loaded with antibiotics for the reconstruction of bilateral tibial fractures in a patient who presented with bone loss and infection after a motorcycle road injury. A 70-year-old man presented open fractures of his both tibiae (proximal involvement on the right side and diaphyseal on the left side). After initial treatment with multiple débridements and the placement of bilateral external fixators, he had bone loss to both tibiae and had developed infections of both legs with multiple organisms identified (Stenotrophomonas maltophilia, Enterobacter cloacae, and Pseudomonas aeruginosa). We used a porous alumina ceramic, designed according to the defects to fill. This ceramic was loaded with antibiotics (gentamicin and vancomycin). The goal was to obtain locally high concentrations of antibiotics to eradicate bacteria that could have remain in the surgical wound. Ceramic parts were placed 4 months after the trauma. Local antibiotic concentrations largely exceeded the pharmacological parameters for antibiotics efficacy. External fixators were removed 3 months after implantation. After a follow-up of more than 1 year, there is no relapse of infection, and the patient resumed walking while ceramic parts were left in place and that bone started colonizing ceramic parts. This ceramic that combines strength and the possibility of antibiotic loading allows thinking of new ways to treat infected fractures with bone loss. Indeed, its mechanical strength provides primary stability, and antibiotics make it possible to secure implantation in an infected area.

Antibiotic-free antimicrobial poly (methyl methacrylate) bone cements: A state-of-the-art review

Prosthetic joint infection (PJI) is the most serious complication following total joint arthroplasty, this being because it is associated with, among other things, high morbidity and low quality of life, is difficult to prevent, and is very challenging to treat/manage. The many shortcomings of antibiotic-loaded poly (methyl methacrylate) (PMMA) bone cement (ALBC) as an agent for preventing and treating/managing PJI are well-known. One is that microorganisms responsible for most PJI cases, such as methicillin-resistant S. aureus, have developed or are developing resistance to gentamicin sulfate, which is the antibiotic in the vast majority of approved ALBC brands. This has led to many research efforts to develop cements that do not contain gentamicin (or, for that matter, any antibiotic) but demonstrate excellent antimicrobial efficacy. There is a sizeable body of literature on these so-called "antibiotic-free antimicrobial" PMMA bone cements (AFAMBCs). The present work is a comprehensive and critical review of this body. In addition to summaries of key trends in results of characterization studies of AFAMBCs, the attractive features and shortcomings of the literature are highlighted. Shortcomings provide motivation for future work, with some ideas being formulation of a new generation of AFAMBCs by, example, adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement, respectively.

Influence of Different Nanometals Implemented in PMMA Bone Cement on Biological and Mechanical Properties

Cemented arthroplasty is a common process to fix prostheses when a patient becomes older and his/her bone quality deteriorates. The applied cements are biocompatible, can transfer loads, and dampen vibrations, but do not provide antibacterial protection. The present work is aimed at the development of cement with antibacterial effectivity achieved with the implementation of nanoparticles of different metals. The powders of Ag, Cu with particles size in a range of 10–30 nm (Cu10) and 70–100 nm (Cu70), AgCu, and Ni were added to PMMA cement. Their influence on compression strength, wettability, and antibacterial properties of cement was assessed. The surface topography of samples was examined with biological and scanning electron microscopy. The mechanical properties were determined by compression tests. A contact angle was observed with a goniometer. The biological tests included an assessment of cytotoxicity (XTT test on human cells Saos-2 line) and bacteria viability exposure (6 months). The cements with Ag and Cu nanopowders were free of bacteria. For AgCu and Ni nanoparticles, the bacterial solution became denser over time and, after 6 months, the bacteria clustered into conglomerates, creating a biofilm. All metal powders in their native form in direct contact reduce the number of eukaryotic cells. Cell viability is the least limited by Ag and Cu particles of smaller size. All samples demonstrated hydrophobic nature in the wettability test. The mechanical strength was not significantly affected by the additions of metal powders. The nanometal particles incorporated in PMMA-based bone cement can introduce long-term resistance against bacteria, not resulting in any serious deterioration of compression strength.