Osteomyelitis of the long bones

A Novel Method to Assess Healing of Segmental Bone Defects using the Induced Membrane Technique

OBJECTIVE

Clinical concerns exist regarding the quality of bony consolidation in the context of the induced membrane technique. This study evaluates the clinical process of bone grafting in the second stage of induced membrane bone union in patients with tibial bone defects to infer the possibility of non-union and establish a reliable and effective evaluation method combined with computed tomography (CT) to assess fracture healing.

METHODS

Patients with tibial bone defects who underwent the induced membrane technique at our hospital between February 2017 and February 2020 were retrospectively analyzed. The Hounsfield unit (HU) values of the patients were evaluated at different times during the second stage of bone grafting. Bone healing at the boundary value of the 120 HU output threshold (-1024 HU-3071 HU) was directionally selected, and the changes in the growth volume of union (new bone volume [selected according to HU value]/bone defect volume) were compared with analyzing individual class bone union. Method 1 involved X-rays revealing that at least three of the four cortices were continuous and at least 2 mm thick, with the patient being pain free. For Method 2, new bone volume (selected according to HU value/bone defect volume) at the stage was compared with analyzing individual class healing. Receiver operating characteristic curve analysis was used for Methods 1 and 2.

RESULTS

A total of 42 patients with a segmental bone defect with a mean age of 40.5 years (40.5 ± 8.3 years) were included. The relationship between bone graft volume and time variation was analyzed by single factor repeated variable analysis (F = 6.477, p = 0.016). Further, curve regression analysis showed that the change in bone graft volume over time presented a logarithmic curve pattern (Y = 0.563 + 0.086 × ln(X), Ra2 = 0.608, p = 0.041). ROC curve analysis showed that Method 2 is superior to Method 1 (AUC: 86.3% vs. 68.3%, p < 0.05).

CONCLUSION

The induced membrane technique could be used to treat traumatic long bone defects, with fewer complications and a higher healing rate. The proposed imaging grading of HU (new bone volume/bone defect volume) can be used as a reference for the quality of bony consolidation with the induced membrane technique.

Prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections

Osteomyelitis is a devastating disease caused by microbial infection in deep bone tissue. Its high recurrence rate and impaired restoration of bone deficiencies are major challenges in treatment. Microbes have evolved numerous mechanisms to effectively evade host intrinsic and adaptive immune attacks to persistently localize in the host, such as drug-resistant bacteria, biofilms, persister cells, intracellular bacteria, and small colony variants (SCVs). Moreover, microbial-mediated dysregulation of the bone immune microenvironment impedes the bone regeneration process, leading to impaired bone defect repair. Despite advances in surgical strategies and drug applications for the treatment of bone infections within the last decade, challenges remain in clinical management. The development and application of tissue engineering materials have provided new strategies for the treatment of bone infections, but a comprehensive review of their research progress is lacking. This review discusses the critical pathogenic mechanisms of microbes in the skeletal system and their immunomodulatory effects on bone regeneration, and highlights the prospects and challenges for the application of tissue engineering technologies in the treatment of bone infections. It will inform the development and translation of antimicrobial and bone repair tissue engineering materials for the management of bone infections.

Staphylococcus aureus epidemiology, pathophysiology, clinical manifestations and application of nano-therapeutics as a promising approach to combat methicillin resistant Staphylococcus aureus

Staphylococcus aureus is a Gram-positive bacterium and one of the most prevalent infectious disease-related causes of morbidity and mortality in adults. This pathogen can trigger a broad spectrum of diseases, from sepsis and pneumonia to severe skin infections that can be fatal. In this review, we will provide an overview of S. aureus and discuss the extensive literature on epidemiology, transmission, genetic diversity, evolution and antibiotic resistance strains, particularly methicillin resistant S. aureus (MRSA). While many different virulence factors that S. aureus produces have been investigated as therapeutic targets, this review examines recent nanotechnology approaches, which employ materials with atomic or molecular dimensions and are being used to diagnose, treat, or eliminate the activity of S. aureus. Finally, having a deeper understanding and clearer grasp of the roles and contributions of S. aureus determinants, antibiotic resistance, and nanotechnology will aid us in developing anti-virulence strategies to combat the growing scarcity of effective antibiotics against S. aureus.

Osteomyelitis is associated with increased anti-inflammatory response and immune exhaustion

Introduction

Osteomyelitis (OMS) is a bone infection causing bone pain and severe complications. A balanced immune response is critical to eradicate infection without harming the host, yet pathogens manipulate immunity to establish a chronic infection. Understanding OMS-driven inflammation is essential for disease management, but comprehensive data on immune profiles and immune cell activation during OMS are lacking.

Methods

Using high-dimensional flow cytometry, we investigated the detailed innate and adaptive systemic immune cell populations in OMS and age- and sex-matched controls.

Results

Our study revealed that OMS is associated with increased levels of immune regulatory cells, namely T regulatory cells, B regulatory cells, and T follicular regulatory cells. In addition, the expression of immune activation markers HLA-DR and CD86 was decreased in OMS, while the expression of immune exhaustion markers TIM-3, PD-1, PD-L1, and VISTA was increased. Members of the T follicular helper (Tfh) cell family as well as classical and typical memory B cells were significantly increased in OMS individuals. We also found a strong correlation between memory B cells and Tfh cells.

Discussion

We conclude that OMS skews the host immune system towards the immunomodulatory arm and that the Tfh memory B cell axis is evident in OMS. Therefore, immune-directed therapies may be a promising alternative for eradication and recurrence of infection in OMS, particularly in individuals and areas where antibiotic resistance is a major concern.

Examining the causal relationship between circulating immune cells and the susceptibility to osteomyelitis: A Mendelian randomization study

BACKGROUND

Osteomyelitis is considered as a deleterious inflammatory condition affecting the bone, primarily attributed to pathogenic infection. However, the underlying factors predisposing individuals to osteomyelitis remain incompletely elucidated. The immune system plays a multifaceted role in the progression of this condition, yet previous observational studies and randomized controlled trials investigating the association between circulating immune cell counts and osteomyelitis have been constrained. In order to address this knowledge gap, we conducted a Mendelian randomization (MR) analysis to evaluate the impact of diverse immune cell counts on the risk of developing osteomyelitis.

METHODS

In our study, we utilized single nucleotide polymorphisms (SNPs) that have been strongly linked to circulating immune cells or specific lymphocyte subtypes, as identified in large-scale genome-wide association studies (GWAS). These SNPs served as instrumental variables (IVs) for our MR analysis. We employed a more relaxed clumping threshold to conduct MR analysis on several related lymphocyte subtypes. To estimate causal effects, we utilized the Wald ratio, as well as the random-effects inverse variance weighted (IVW) and weighted median (WM) methods. To enhance the credibility of our results, we performed F-statistic calculations and a series of sensitivity analyses.

RESULTS

Our findings revealed a significant correlation between the absolute count of circulating lymphocytes and the risk of osteomyelitis [odds ratio(OR) 1.20；95 % confidence interval (CI), 1.08-1.32；P = 0.0005]. Furthermore, we identified a causal relationship between the absolute count of CD8+ T cells and susceptibility to osteomyelitis (OR 1.16; 95 % CI, 1.04-1.30; P = 0.0098). Importantly, these findings remained robust across a wide range of sensitivity analyses.

CONCLUSION

Through our MR analysis, we have provided evidence supporting a causal relationship between genetic predisposition to higher circulating immune cell counts and an increased risk of osteomyelitis. Specifically, our findings highlight the association between elevated CD8+ T cell counts and a heightened susceptibility to osteomyelitis. These results offer valuable insights for the future exploration of immunotherapy approaches in the management of osteomyelitis.

Management of a Partially Treated Case of Chronic Osteomyelitis of the Hard Palate and Maxillary Sinus

Osteomyelitis affects bones, including both cortex and medulla. It influences the mandible more frequently than the maxilla. Probable etiologic factors include foci of infection or trauma; however, the hematogenous spread of infection from a distant site is also a causative factor. Staphylococcus is the common organism involved in the causation. Clinical symptoms include signs of inflammation, pus drainage, fistulous or sinus tracts, wound disintegration, erythema, and raised local temperatures. Laboratory diagnosis with the evaluation of white blood cell count, rate of erythrocyte sedimentation, and C-reactive protein proves vitally significant. Radiographic evaluation reveals sequestra and bone destruction in the affected region. Histopathology of the lesion is confirmatory for the final diagnosis, which helps in the formulation of an appropriate management strategy. The treatment regimen usually focuses on thorough debridement of the necrotic material and an antibiotic regimen. This case report describes a male patient aged 45 years presenting with a palatal ulcer, severe halitosis, and speech difficulty. He has suffered from type II diabetes mellitus for four years. A radiological examination was carried out. Treatment was performed with surgical debridement of necrotic maxillary bone and curettage of bilateral maxillary and ethmoid sinuses under general anesthesia. Results of histopathological evaluation of the curetted material from the maxillary and ethmoid sinuses revealed osteomyelitis of the maxilla.

Assessing the effectiveness of intramedullary nailing for tibial shaft fractures in a low-income setting: a prospective study in Yemen

BACKGROUND

Tibial shaft fractures are common injuries that can be treated with various methods, including interlocked intramedullary nail (IMN). However, there is limited data on the clinical outcomes of IMN for tibial shaft fractures in Yemen.

OBJECTIVE

To evaluate the clinical outcomes of primary IMN for tibial shaft fractures in Yemen.

METHODS

This was a prospective study of 134 patients who underwent primary IMN for tibial shaft fractures et al.-Thawra Modern General Hospital in Sana'a, Yemen, between June 2016 and June 2020. The patients were between 18 and 70 years old, and the fractures were classified according to the AO classification system. The fractures were treated with IMN using a standard technique. The patients were followed up for a minimum of 2 years. The outcome measures included union time, complications, and functional scores.

RESULTS

The mean union time was 17 weeks. The overall complication rate was 18.7%. The most common complications were infection (8.2%), delayed union (6.7%), and nonunion (3.7%). The mean functional scores at the final follow-up were 91.4 for the Knee Society Score and 90.2 for the American Orthopaedic Foot and Ankle Society Score.

CONCLUSION

Primary IMN is an effective and reliable method for treating tibial shaft fractures in Yemen, with acceptable union time, complication rate, and functional outcomes.

Osteomyelitis Masquerading as Cellulitis: A Case Report

Osteomyelitis, a significant global healthcare issue, often results from infections related to open fractures, surgery, or conditions like diabetic foot ulcers. This report describes a case of osteomyelitis in a 62-year-old female with various pre-existing health conditions. The patient initially presented with swelling, pain, and difficulty walking in the right lower extremity, accompanied by systemic symptoms. Despite an initial diagnosis of cellulitis and treatment with ceftriaxone, a subsequent CT scan revealed a pretibial abscess and confirmed osteomyelitis caused by pan-sensitive Escherichia coli. Surgical debridement was performed, and the patient received six weeks of intravenous antibiotics. Hence, a heightened level of suspicion is essential to facilitate a timely diagnosis of osteomyelitis and enhance long-term prognosis. The case underscores the importance of a multidisciplinary approach, including meticulous surgical intervention and tailored antimicrobial therapy, in achieving positive outcomes for osteomyelitis patients.

Pharmacological elevation of sphingosine-1-phosphate by S1P lyase inhibition accelerates bone regeneration after post-traumatic osteomyelitis

Posttraumatic osteomyelitis and the ensuing bone defects are a debilitating complication after open fractures with little therapeutic options. We have recently identified potent osteoanabolic effects of sphingosine-1-phosphate (S1P) signalling and have now tested whether it may beneficially affect bone regeneration after infection. We employed pharmacological S1P lyase inhibition by 4-deoxypyrodoxin (DOP) to raise S1P levels in vivo in an unicortical long bone defect model of posttraumatic osteomyelitis in mice. In a translational approach, human bone specimens of clinical osteomyelitis patients were treated in organ culture in vitro with DOP. Bone regeneration was assessed by μCT, histomorphometry, immunohistology and gene expression analysis. The role of S1P receptors was addressed using S1PR3 deficient mice. Here, we present data that DOP treatment markedly enhanced osteogenesis in posttraumatic osteomyelitis. This was accompanied by greatly improved osteoblastogenesis and enhanced angiogenesis in the callus accompanied by osteoclast-mediated bone remodelling. We also identified the target of increased S1P to be the S1PR3 as S1PR3-/- mice showed no improvement of bone regeneration by DOP. In the human bone explants, bone mass significantly increased along with enhanced osteoblastogenesis and angiogenesis. Our data suggest that enhancement of S1P/S1PR3 signalling may be a promising therapeutic target for bone regeneration in posttraumatic osteomyelitis.

Hematoma-like dynamic hydrogelation through natural glycopeptide molecular recognition for infected bone fracture repair

Infected bone fractures remain a major clinical challenge for orthopedic surgeons. From a tissue regeneration perspective, biomaterial scaffolds with antibacterial and osteoinductive activities are highly desired, while advanced materials capable of mimicking the pathological microenvironment during the healing process of infected tissues remain an area deserving more research. Hematoma, the gel-like blood coagulum, plays an essential role in bone fracture repair because of its ability to serve as a dynamic and temporary scaffold with cytokines for both pathogen elimination and tissue healing. In light of this, we designed a dynamic hydrogel with hematoma-like antimicrobial or reparative performance for infected bone fracture repair in this study. The proposed dynamic hydrogel network was based on the reversible recognition of a natural glycopeptide antibiotic vancomycin (Van) and its target dipeptide D-Ala-D-Ala (AA), which could serve as a hematoma-like scaffold for obliterating bacteria in the fracture region and promoting bone repair by introducing an endogenous osteogenic peptide (OGP). In vivo experiments demonstrated that the hydrogel could rapidly eradicate bacteria, improve bone regeneration and restore the local inflammatory microenvironment. Together, findings from this study imply that the use of hematoma-like dynamic hydrogel could lead to a biomimetic revolution in surgical strategies against susceptible bone fractures.

A better roadmap for designing novel bioactive glasses: effective approaches for the development of innovative revolutionary bioglasses for future biomedical applications

The introduction of bioactive glasses (BGs) precipitated a paradigm shift in the medical industry and opened the path for the development of contemporary regenerative medicine driven by biomaterials. This composition can bond to live bone and can induce osteogenesis by the release of physiologically active ions. 45S5 BG products have been transplanted effectively into millions of patients around the world, primarily to repair bone and dental defects. Over the years, many other BG compositions have been introduced as innovative biomaterials for repairing soft tissue and delivering drugs. When research first started, many of the accomplishments that have been made today were unimaginable. It appears that the true capacity of BGs has not yet been realized. Because of this, research involving BGs is extremely fascinating. However, to be successful, it requires interdisciplinary cooperation between physicians, glass chemists, and bioengineers. The present paper gives a picture of the existing clinical uses of BGs and illustrates key difficulties deserving to be faced in the future. The challenges range from the potential for BGs to be used in a wide variety of applications. We have high hopes that this paper will be of use to both novice researchers, who are just beginning their journey into the world of BGs, as well as seasoned scientists, in that it will promote conversation regarding potential additional investigation and lead to the discovery of innovative medical applications for BGs.

Nanocomposite orthopaedic bone cement combining long-acting dual antimicrobial drugs

Antibiotic loaded bone cements are widely used in total joint replacement (TJR); despite many limitations such as a burst release which leads to antibiotic concentration below inhibitory levels and possibly contributing to the selection of antibiotic resistant strains. In order to address such limitations and to simultaneously address antibiotic resistance and short-term antimicrobial activity, we developed a nanocomposite bone cement capable of providing a controlled release of antimicrobial agents from bone cement to act as prophylaxis or treatment against prosthetic joint infections (PJIs). Gentamicin and chlorhexidine were loaded in combination on silica nanoparticles surface using layer-by-layer coating technique (LbL) combining hydrolysable and non-hydrolysable polymers. The drug release from the nanocomposite continued for >50 days at concentrations higher than the commercial formulation containing the same amount of antimicrobial drugs, where burst release for few days were observed. Moreover, the nanocomposite bone cement showed superior antimicrobial inhibition without adversely affecting the mechanical properties or the ability of osteoblasts to grow. In vivo experiments with an infected bone lesion model along with mass-spectrometric analysis also provided further evidence of efficacy and safety of the implanted nanocomposite material as well as its prolonged drug eluting profile. The developed nanocomposite bone cement has the potential to reduce PJIs and enable treatment of resistant established infections; moreover, the newly developed LbL based nano-delivery system may also have wider applications in reducing the threat posed by antimicrobial resistance.

Parathyroid hormone therapy improves MRSA-infected fracture healing in a murine diabetic model

Introduction

Diabetes mellitus (DM) impairs fracture healing and is associated with susceptibility to infection, which further inhibits fracture healing. While intermittent parathyroid hormone (1-34) (iPTH) effectively improves fracture healing, it is unknown whether infection-associated impaired fracture healing can be rescued with PTH (teriparatide).

Methods

A chronic diet-induced type 2 diabetic mouse model was used to yield mice with decreased glucose tolerance and increased blood glucose levels compared to lean-fed controls. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated in a surgical tibia fracture model to simulate infected fracture, after which mice were treated with a combination of antibiotics and adjunctive teriparatide treatment. Fracture healing was assessed by Radiographic Union Scale in Tibial Fractures (RUST), micro-computed tomography (μCT), biomechanical testing, and histology.

Results

RUST score was significantly poorer in diabetic mice compared to their lean nondiabetic counterparts. There were concomitant reductions in micro-computed tomography (μCT) parameters of callus architecture including bone volume/total volume, trabecular thickness, and total mineral density in type 2 diabetes mellitus (T2DM) mice. Biomechanicaltesting of fractured femora demonstrated diminished torsional rigidity, stiffness, and toughness to max torque. Adjuvant teriparatide treatment with systemic antibiotic therapy improved numerous parameters of bone microarchitecture bone volume, increased connectivity density, and increased trabecular number in both the lean and T2DM group. Despite the observation that poor fracture healing in T2DM mice was further impaired by MRSA infection, adjuvant iPTH treatment significantly improved fracture healing compared to antibiotic treatment alone in infected T2DM fractures.

Discussion

Our results suggest that teriparatide may constitute a viable adjuvant therapeutic agent to improve bony union and bone microarchitecture to prevent the development of septic nonunion under diabetic conditions.

Effectiveness of an Antibiotic-impregnated Bioabsorbable Carrier for the Treatment of Chronic Intramedullary and Diffuse Osteomyelitis

Aim

The surgical management of chronic intramedullary osteomyelitis involves debridement of affected non-viable tissue and the use of antibiotics. Where surgery leaves a cavity, dead-space management is often through antibiotic-impregnated bone cement. These depots of local antibiotics are variable in elution properties and need removal. We review our unit's experience using a bioabsorbable synthetic calcium sulphate to deliver gentamicin as an adjunct in the treatment of osteomyelitis involving the medullary canal.

Materials and methods

We retrospectively reviewed 34 patients with chronic osteomyelitis who were treated using this method in our institute. Variables recorded included aetiology, previous interventions, diagnostic criteria, radiological features, serology, and microbiology. The Cierny-Mader system was used to classify. Follow-up involved a survival analysis to time to recurrence, clinical and functional assessment (AOFAS-Ankle/IOWA knee/Oxford Hip/DASH scores) and a general health outcome questionnaire (SF36). The primary outcome measure was clinical recurrence of infection.

Results

There were 24 male and 10 female patients. The mean age at presentation was 47 years (20-67). Clinical, laboratory, radiological, and patient reported outcomes were obtained at a median follow-up of 2.5 years (1.4-6.6 years). The bones involved were the femur (14, 41%), tibia (16, 47%), radius (1, 3%), and humerus (3, 9%). There were 13 cases classified as Cierny-Mader stage IV (diffuse with intramedullary osteomyelitis) and 21 cases as Cierny-Mader stage I. The median Oxford Hip score was 38 (11 patients, range 9-48). The median AOFAS score was 78 (14 patients, range 23-100). The median IOWA knee score was 71 (25 patients, range 22-95). The median DASH score was 33 (2 patients, range 1.7-64.2). There were two recurrences. The treatment success to date is 94%.

Conclusion

In our series of patients, bioabsorbable carriers of antibiotics appear to be effective adjuncts to surgical treatment of osteomyelitis and were associated with high clinical success rates.

How to cite this article

Selvaratnam V, Roche A, Narayan B, et al. Effectiveness of an Antibiotic-impregnated Bioabsorbable Carrier for the Treatment of Chronic Intramedullary and Diffuse Osteomyelitis. Strategies Trauma Limb Reconstr 2023;18(3):148-154.

Bacterial Isolates and Their Antimicrobial Susceptibility Profile in Osteomyelitis Patients: An Experience From a Tertiary Care Center in a Hilly Area of Uttarakhand

Osteomyelitis, an infection related to bone and bone marrow, is very diverse in its pathophysiology and clinical presentation; hence, it is considered one of the most difficult-to-treat infections. The present study is aimed at assessing the microbiological profile of osteomyelitis and related antimicrobial susceptibility patterns in patients attending a tertiary care center in Uttarakhand, India, over a period of one year (January to December 2019). In aerobic culture, 58/105 (55.2%) bacterial isolates were detected. In addition, Staphylococcus aureus was the most common isolate, and amongst Gram-negative bacilli, most isolates that grew on culture were Escherichia coli (22.4%). Out of 21 S. aureus isolates, methicillin resistance was detected in nine [9/21 (42%)] cases, which is a matter of concern. Hence, proper training and application of antimicrobial stewardship are the need of the hour so that clinicians can initiate targeted therapy as early as possible.

Identification of molecular subgroups in osteomyelitis induced by staphylococcus aureus infection through gene expression profiles

BACKGROUND

Staphylococcus aureus (S. aureus) infection-induced osteomyelitis (OM) is an inflammatory bone disease accompanied by persistent bone destruction, and the treatment is challenging because of its tendency to recur. Present study was aimed to explore the molecular subgroups of S. aureus infection-induced OM and to deepen the mechanistic understanding for molecularly targeted treatment of OM.

METHODS

Integration of 164 OM samples and 60 healthy samples from three datasets of the Gene Expression Omnibus (GEO) database. OM patients were classified into different molecular subgroups based on unsupervised algorithms and correlations of clinical characteristics between subgroups were analyzed. Next, The CIBERSORT algorithm was used to evaluate the proportion of immune cell infiltration in different OM subgroups. Weighted gene co-expression analysis (WGCNA) was used to identify different gene modules and explore the relationship with clinical characteristics, and further annotated OM subgroups and gene modules by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis.

RESULTS

Two subgroups with excellent consistency were identified in this study, subgroup and hospital length of stay were independent predictors of OM. Compared with subgroup I, OM patients in subgroup II had longer hospital length of stay and more severe disease. Meanwhile, the infiltration proportions of monocytes and macrophages M0 were higher in patients of OM subgroup II. Finally, combined with the characteristics of the KEGG enrichment modules, the expression of osteoclast differentiation-related genes such as CTSK was upregulated in OM subgroup II, which may be closely associated with more severe OM patients.

CONCLUSION

The current study showed that OM subgroup II had longer hospital length of stay and more severe disease, the osteoclast differentiation pathway and the main target CTSK contribute to our deeper understanding for the molecular mechanisms associated with S. aureus infection-induced OM, and the construction of molecular subgroups suggested the necessity for different subgroups of patients to receive individualized treatment.

A possible case of orbital osteomyelitis from the medieval cemetery of Sant' Agostino in Caravate (Varese, Northern Italy)

OBJECTIVES

This paper aims to present one of the first osteoarchaeological cases of orbital osteomyelitis and provides the best diagnostic criteria to identify its pathophysiological changes.

MATERIALS

A well-preserved skeleton of an adult male from the medieval cemetery of Sant' Agostino in Caravate, Italy.

METHODS

Macroscopic, tomographic, and histological analyses were performed using standard methods.

RESULTS

The skeleton shows irregularities in the architecture of the left supraorbital margin. CT analysis reveals the presence of a radiotransparent area involving the diploe and the external cranial table. This area is lateromedially oval-shaped and bordered by a thick irregular radiodense rim, associated with the presence of a cloaca on the roof of the orbit and surrounding periosteal reaction. Microscopic examination shows the formation of a thin layer of cortical bone and an osteoid-like matrix.

CONCLUSION

A careful differential diagnosis based on macroscopic, radiological, and histological evidence suggests a case of orbital osteomyelitis.

SIGNIFICANCE

This case study represents one of the few osteoarchaeological evaluations of ocular chronic osteomyelitis diagnosed using macroscopic skeletal, computed tomography, and histological analysis. As such, it provides a reference and an investigative criterion for future cases.

LIMITATIONS

The diagnosis cannot be stated with certainty, and only probable diagnoses can be proposed. Although we referred especially to clinical literature, it is necessary to consider that the severity of conditions may be modified by modern medical intervention.

SUGGESTION FOR FURTHER RESEARCH

This case provides further insights into the presence of this condition in the past.

Exploring the Antimicrobial Activity of Sodium Titanate Nanotube Biomaterials in Combating Bone Infections: An In Vitro and In Vivo Study

The majority of bone and joint infections are caused by Gram-positive organisms, specifically staphylococci. Additionally, gram-negative organisms such as E. coli can infect various organs through infected wounds. Fungal arthritis is a rare condition, with examples including Mucormycosis (Mucor rhizopus). These infections are difficult to treat, making the use of novel antibacterial materials for bone diseases crucial. Sodium titanate nanotubes (NaTNTs) were synthesized using the hydrothermal method and characterized using a Field Emission Scanning Electron Microscope (FESEM), High-Resolution Transmission Electron Microscope (HRTEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and Zeta sizer. The antibacterial and antifungal activity of the NaTNT framework nanostructure was evaluated using Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), Disc Diffusion assays for bacterial activity, and Minimum Fungicidal Concentration (MFC) for antifungal investigation. In addition to examining in vivo antibacterial activity in rats through wound induction and infection, pathogen counts and histological examinations were also conducted. In vitro and in vivo tests revealed that NaTNT has substantial antifungal and antibacterial effects on various bone-infected pathogens. In conclusion, current research indicates that NaTNT is an efficient antibacterial agent against a variety of microbial pathogenic bone diseases.

Flourishing Antibacterial Strategies for Osteomyelitis Therapy

Osteomyelitis is a destructive disease of bone tissue caused by infection with pathogenic microorganisms. Because of the complex and long-term abnormal conditions, osteomyelitis is one of the refractory diseases in orthopedics. Currently, anti-infective therapy is the primary modality for osteomyelitis therapy in addition to thorough surgical debridement. However, bacterial resistance has gradually reduced the benefits of traditional antibiotics, and the development of advanced antibacterial agents has received growing attention. This review introduces the main targets of antibacterial agents for treating osteomyelitis, including bacterial cell wall, cell membrane, intracellular macromolecules, and bacterial energy metabolism, focuses on their mechanisms, and predicts prospects for clinical applications.

Neutralization of Staphylococcus aureus Protein A Prevents Exacerbated Osteoclast Activity and Bone Loss during Osteomyelitis

Osteomyelitis caused by Staphylococcus aureus is an important and current health care problem worldwide. Treatment of this infection frequently fails not only due to the increasing incidence of antimicrobial-resistant isolates but also because of the ability of S. aureus to evade the immune system, adapt to the bone microenvironment, and persist within this tissue for decades. We have previously demonstrated the role of staphylococcal protein A (SpA) in the induction of exacerbated osteoclastogenesis and increased bone matrix degradation during osteomyelitis. The aim of this study was to evaluate the potential of using anti-SpA antibodies as an adjunctive therapy to control inflammation and bone damage. By using an experimental in vivo model of osteomyelitis, we demonstrated that the administration of an anti-SpA antibody by the intraperitoneal route prevented excessive inflammatory responses in the bone upon challenge with S. aureus. Ex vivo assays indicated that blocking SpA reduced the priming of osteoclast precursors and their response to RANKL. Moreover, the neutralization of SpA was able to prevent the differentiation and activation of osteoclasts in vivo, leading to reduced expression levels of cathepsin K, reduced expression of markers associated with abnormal bone formation, and decreased trabecular bone loss during osteomyelitis. Taken together, these results demonstrate the feasibility of using anti-SpA antibodies as an antivirulence adjunctive therapy that may prevent the development of pathological conditions that not only damage the bone but also favor bacterial escape from antimicrobials and the immune system.

Cranial trephination and infectious disease in the Eastern Mediterranean: The evidence from two elite brothers from Late Bronze Megiddo, Israel

Here we present the paleopathological profiles of two young adult males, identified as brothers through ancient DNA analysis, who were buried together beneath the floor of an elite early Late Bronze Age I (ca. 1550-1450 BC) domestic structure at the urban center of Megiddo (modern Israel). Both individuals displayed uncommon morphological variants related to developmental conditions, and each exhibited extensive bone remodeling consistent with chronic infectious disease. Additionally, one brother had a healed fracture of the nose, as well as a large square piece of bone cut from the frontal bone (cranial trephination). We consider the potential etiologies for the appearance of the skeletal anomalies and lesions. Based on the bioarchaeological context, we propose that a shared epigenetic landscape predisposed the brothers to acquiring an infectious disease and their elite status privileged them enough to endure it. We then contextualize these potential illnesses and disorders with the trephination procedure. The infrequency of trephination in the region indicates that only selected individuals could access such a procedure, and the severity of the pathological lesions suggests the procedure was possibly intended as curative to deteriorating health. Ultimately, both brothers were buried with the same rites as others in their community, thus demonstrating their continued integration in society even after death.

Surgical Debridement for Acute and Chronic Osteomyelitis in Children

Background

Osteomyelitis is an infection of the bone that commonly occurs in pediatric populations. First-line treatment most often involves a course of antibiotics. In recent studies, surgical debridement, in addition to antibiotics, has been shown to provide positive clinical and functional outcomes in children. Debridement is most often indicated in patients with an abscess or in those who do not respond to empiric antibiotic therapy; however, there are limited video resources describing this technique in pediatric patients.

Description

The key steps of the procedure, which are demonstrated in the present video article, are (1) preoperative planning, (2) positioning, (3) subperiosteal exposure and debridement, (4) cortical window creation, (5) irrigation, (6) adjunctive treatment, (7) drain placement, (8) wound closure, (9) dressing and immobilization, and (10) wound check and drain removal.

Alternatives

Nonoperative treatment is usually indicated for acute osteomyelitis in which patients present with little to no necrotic tissue or abscess formation. In these cases, a course of broad-spectrum antibiotics may be sufficient for a cure.

Rationale

This procedure allows for the removal of necrotic bone and soft tissue, thus facilitating the recovery process. It also allows for the retrieval of tissue samples that may be used to guide selection of the appropriate antibiotic therapy. Surgical debridement is a safe and reliable technique that has been associated with positive long-term outcomes.

Expected Outcomes

We expect that some patients will require repeat surgical debridement procedures to decrease pathogen burden and prevent future complications. However, we expect that the majority of patients who undergo surgical debridement for uncomplicated osteomyelitis will recover full functionality of the affected limb with no associated long-term sequelae10.

Important Tips

Understand preoperative imaging to identify areas of infection, localize critical structures and the physis, and plan surgical approaches.Use extensile approaches and preserve vascularity during the approach.Perform subperiosteal dissection and create a cortical window to debride areas of infection, but avoid excessive periosteal stripping.Close the dead space and wound in a layered manner.

Acronyms and Abbreviations

MRI = magnetic resonance imagingK-wire = Kirschner wireMRSA = methicillin-resistant Staphylococcus aureusPDS = polydiaxonone.

Antibiotic coated nails: Rationale, development, indications and outcomes

The concept of antibiotic-coated implants, mainly coated intramedullary nails, has become increasingly used for the treatment of fracture related infections. After a long period of hand-made implants, commercially fabricated implants combine several benefits. Antibiotic-coated nails constitute a solid treatment option for unstable diaphyseal infections with fractures or non-unions. They release high concentrations of antibiotics locally, while retaining reduction and providing axial stability. This review aims to provide an overview about the background, the development, the indications, the treatment strategies and the outcomes of antibiotic-coated intramedullary nails.

Microbiology of fracture related infections

Fracture related infection remains a challenging complication that creates a heavy burden for orthopaedic trauma patients, their families, treating physicians and healthcare systems. Even current curative approaches (radical debridement, revision surgery and long-term antibiotics) often result in significant socioeconomic costs and the risk of life-long functional impairment to the patient. The prevalence of osteomyelitis due to trauma and surgical complications does not seem to be diminishing in our society and the emergence of antimicrobial resistance is a major health related concern with global relevance. Despite multi-drug resistant bacteria being on the rise universally, perioperative antibiotic prophylaxis in orthopaedic trauma care has only slightly changed in the last 25 years. Staphylococcus infections remain an increasing global concern, partially due to the resistance mechanisms developed by staphylococci to evade the host immune system and antibiotic treatment, and as such antibiotics are becoming increasingly ineffective. This paper will address fracture related infections in trauma patients, looking at the bacteriology of these infections, its clinical implications and evolving nature.

Role of 18F-FDG PET-CT in Pre-Operative Planning of Surgical Debridement in Chronic Osteomyelitis

PURPOSE

Osteomyelitis is a challenge in diagnosis and treatment. 18F-FDG PET-CT provides a non-invasive tool for diagnosing and localizing osteomyelitis with a sensitivity reaching 94% and specificity reaching 100%. We aimed to assess the agreement in identifying the geographic area of infected bone and planned resection on plain X-ray versus 18F-FDG PET-CT.

METHODS

Clinical photos and X-rays of ten osteomyelitis patients were shown to ten consultant surgeons; they were asked to draw the area of infection and extent of planned surgical debridement; data will be compared to 18F-FDG PET-CT results.

RESULTS

We tested the agreement between the surgeons in every parameter. Regarding height, there was poor agreement between surgeons. Regarding perimeter, the ten surgeons showed low-moderate agreement. The ten surgeons showed a low-moderate agreement for circularity. Results document the variability of assessment and judgement based on plain X-rays. In comparison to PET-CT, All parameters were significantly different in favour of ¹⁸F-FDG PET-CT over X-ray (P < 0.001).

CONCLUSION

¹⁸F FDG PET-CT provides a three-dimensional tool for localizing the exact location of the infected bone and differentiating it from the normal bone. Thus, it could be beneficial in precise pre-operative planning and surgical debridement of chronic osteomyelitis.

Context-Dependent Roles for Toll-Like Receptors 2 and 9 in the Pathogenesis of Staphylococcus aureus Osteomyelitis

Staphylococcus aureus is the major causative agent of bacterial osteomyelitis, an invasive infection of bone. Inflammation generated by the immune response to S. aureus contributes to bone damage by altering bone homeostasis. Increases in the differentiation of monocyte lineage cells into bone-resorbing osteoclasts (osteoclastogenesis) promote bone loss in the setting of osteomyelitis. In this study, we sought to define the role of Toll-like receptor (TLR) signaling in the pathogenesis of S. aureus osteomyelitis. We hypothesized that S. aureus-sensing TLRs 2 and 9, both of which are known to alter osteoclastogenesis in vitro, promote pathological changes to bone, including increased osteoclast abundance, bone loss, and altered callus formation during osteomyelitis. Stimulation of osteoclast precursors with S. aureus supernatant increased osteoclastogenesis in a TLR2-dependent, but not a TLR9-dependent, manner. However, in vivo studies using a posttraumatic murine model of osteomyelitis revealed that TLR2-null mice experienced similar bone damage and increased osteoclastogenesis compared to wild type (WT) mice. Therefore, we tested the hypothesis that compensation between TLR2 and TLR9 contributes to osteomyelitis pathogenesis. We found that mice deficient in both TLR2 and TLR9 (Tlr2/9^-/-) have decreased trabecular bone loss in response to infection compared to WT mice. However, osteoclastogenesis is comparable between WT and Tlr2/9^-/- mice, suggesting that alternative mechanisms enhance osteoclastogenesis in vivo during osteomyelitis. Indeed, we discovered that osteoclast precursors intracellularly infected with S. aureus undergo significantly increased osteoclast formation, even in the absence of TLR2 and TLR9. These results suggest that TLR2 and TLR9 have context-dependent roles in the alteration of bone homeostasis during osteomyelitis.

Chronic fracture and osteomyelitis in a large-bodied ornithomimosaur with implications for the identification of unusual endosteal bone in the fossil record

Paleopathological diagnoses provide key information on the macroevolutionary origin of disease as well as behavioral and physiological inferences that are inaccessible via direct observation of extinct organisms. Here we describe the external gross morphology and internal architecture of a pathologic right second metatarsal (MMNS VP-6332) of a large-bodied ornithomimid (~432 kg) from the Santonian (Upper Cretaceous) Eutaw Formation in Mississippi, using a combination of X-ray computed microtomography (microCT) and petrographic histological analyses. X-ray microCT imaging and histopathologic features are consistent with multiple complete, oblique to comminuted, minimally displaced mid-diaphyseal cortical fractures that produce a "butterfly" fragment fracture pattern, and secondary osteomyelitis with a bone fistula formation. We interpret this as evidence of blunt force trauma to the foot that could have resulted from intra- or interspecific competition or predator-prey interaction, and probably impaired the function of the metatarsal as a weight-bearing element until the animal's death. Of particular interest is the apparent decoupling of endosteal and periosteal pathological bone deposition in MMNS VP-6332, which produces transverse sections exhibiting homogenously thick endosteal pathological bone in the absence of localized periosteal reactive bone. These distribution and depositional patterns are used as criteria for ruling out a pathological origin in favor of a reproductive one for unusual endosteal bone in fossil specimens. On the basis of MMNS VP-6332, we suggest caution in their use to substantiate a medullary bone identification in extinct archosaurians.

The Medium Composition Impacts Staphylococcus aureus Biofilm Formation and Susceptibility to Antibiotics Applied in the Treatment of Bone Infections

The biofilm-associated infections of bones are life-threatening diseases, requiring application of dedicated antibiotics in order to counteract the tissue damage and spread of microorganisms. The in vitro analyses on biofilm formation and susceptibility to antibiotics are frequently carried out using methods that do not reflect conditions at the site of infection. To evaluate the influence of nutrient accessibility on Staphylococcus aureus biofilm development in vitro, a cohesive set of analyses in three different compositional media was performed. Next, the efficacy of four antibiotics used in bone infection treatment, including gentamycin, ciprofloxacin, levofloxacin, and vancomycin, against staphylococcal biofilm, was also assessed. The results show a significant reduction in the ability of biofilm to grow in a medium containing elements occurring in the serum, which also translated into the diversified changes in the efficacy of used antibiotics, compared to the setting in which conventional media were applied. The differences indicate the need for implementation of adequate in vitro models that closely mimic the infection site. The results of the present research may be considered an essential step toward the development of in vitro analyses aiming to accurately indicate the most suitable antibiotic to be applied against biofilm-related infections of bones.

Update on MRI findings of osteomyelitis of long bones in the adult population

OBJECTIVES

To evaluate the usefulness of new and established MRI signs of osteomyelitis in long bones in adults.

METHODS

All patient records over a 9-year period with clinical or MRI suspicion for osteomyelitis were retrospectively reviewed, using strict criteria for proof of infection. Two musculoskeletal radiologists independently reviewed the MRIs of proven osteomyelitis.

RESULTS

Out of 45 MRIs of confirmed osteomyelitis, 2 MRIs (4%) did not show confluent low-signal intensity on T1-weighted images, but all showed confluent high-signal intensity on T2-weighted images. Central hypoenhancing regions of marrow without abscess formation were found in 15-18/35 (43-51%) cases where gadolinium was given. We often found multiple foci of marrow replacement in the same bone. The areas of marrow involvement often had an irregular contour. Penumbra sign, marrow fat globules, and sequestra were uncommon.

CONCLUSION

Multiple foci of bone marrow signal abnormalities, an irregular contour of marrow abnormality, and central marrow hypoenhancement without abscess are common signs of osteomyelitis of long bones in adults. Confluent low T1-signal intensity is not always present.

A Comparative Case Study between Gallium-67 Citrate Scintigraphy and Gallium-68 Citrate Positron Emission Tomography-Computed Tomography in Bone Infection

Bone infections are a common problem, and early diagnosis and intervention can lead to better clinical outcomes and prognoses. Here, we compare the well-known tracers Gallium-67 (Ga-67) citrate versus Ga-68 citrate in the diagnosis of infections.

Mini Review Therapeutic Strategies Targeting for Biofilm and Bone Infections

Bone infection results in a complex inflammatory response and bone destruction. A broad spectrum of bacterial species has been involved for jaw osteomyelitis, hematogenous osteomyelitis, vertebral osteomyelitis or diabetes mellitus, such as Staphylococcus aureus (S. aureus), coagulase-negative Staphylococcus species, and aerobic gram-negative bacilli. S. aureus is the major pathogenic bacterium for osteomyelitis, which results in a complex inflammatory response and bone destruction. Although various antibiotics have been applied for bone infection, the emergence of drug resistance and biofilm formation significantly decrease the effectiveness of those agents. In combination with gram-positive aerobes, gram-negative aerobes and anaerobes functionally equivalent pathogroups interact synergistically, developing as pathogenic biofilms and causing recurrent infections. The adhesion of biofilms to bone promotes bone destruction and protects bacteria from antimicrobial agent stress and host immune system infiltration. Moreover, bone is characterized by low permeability and reduced blood flow, further hindering the therapeutic effect for bone infections. To minimize systemic toxicity and enhance antibacterial effectiveness, therapeutic strategies targeting on biofilm and bone infection can serve as a promising modality. Herein, we focus on biofilm and bone infection eradication with targeting therapeutic strategies. We summarize recent targeting moieties on biofilm and bone infection with peptide-, nucleic acid-, bacteriophage-, CaP- and turnover homeostasis-based strategies. The antibacterial and antibiofilm mechanisms of those therapeutic strategies include increasing antibacterial agents’ accumulation by bone specific affinity, specific recognition of phage-bacteria, inhibition biofilm formation in transcription level. As chronic inflammation induced by infection can trigger osteoclast activation and inhibit osteoblast functioning, we additionally expand the potential applications of turnover homeostasis-based therapeutic strategies on biofilm or infection related immunity homeostasis for host-bacteria. Based on this review, we expect to provide useful insights of targeting therapeutic efficacy for biofilm and bone infection eradication.

Role of Animal Models to Advance Research of Bacterial Osteomyelitis

Osteomyelitis is an inflammatory bone disease typically caused by infectious microorganisms, often bacteria, which causes progressive bone destruction and loss. The most common bacteria associated with chronic osteomyelitis is Staphylococcus aureus. The incidence of osteomyelitis in the United States is estimated to be upwards of 50,000 cases annually and places a significant burden upon the healthcare system. There are three general categories of osteomyelitis: hematogenous; secondary to spread from a contiguous focus of infection, often from trauma or implanted medical devices and materials; and secondary to vascular disease, often a result of diabetic foot ulcers. Independent of the route of infection, osteomyelitis is often challenging to diagnose and treat, and the effect on the patient's quality of life is significant. Therapy for osteomyelitis varies based on category and clinical variables in each case. Therapeutic strategies are typically reliant upon protracted antimicrobial therapy and surgical interventions. Therapy is most successful when intensive and initiated early, although infection may recur months to years later. Also, treatment is accompanied by risks such as systemic toxicity, selection for antimicrobial drug resistance from prolonged antimicrobial use, and loss of form or function of the affected area due to radical surgical debridement or implant removal. The challenges of diagnosis and successful treatment, as well as the negative impacts on patient's quality of life, exemplify the need for improved strategies to combat bacterial osteomyelitis. There are many in vitro and in vivo investigations aimed toward better understanding of the pathophysiology of bacterial osteomyelitis, as well as improved diagnostic and therapeutic strategies. Here, we review the role of animal models utilized for the study of bacterial osteomyelitis and their critically important role in understanding and improving the management of bacterial osteomyelitis.

Role of Implantable Drug Delivery Devices with Dual Platform Capabilities in the Prevention and Treatment of Bacterial Osteomyelitis

As medicine advances and physicians are able to provide patients with innovative solutions, including placement of temporary or permanent medical devices that drastically improve quality of life of the patient, there is the persistent, recurring problem of chronic bacterial infection, including osteomyelitis. Osteomyelitis can manifest as a result of traumatic or contaminated wounds or implant-associated infections. This bacterial infection can persist as a result of inadequate treatment regimens or the presence of biofilm on implanted medical devices. One strategy to mitigate these concerns is the use of implantable medical devices that simultaneously act as local drug delivery devices (DDDs). This classification of device has the potential to prevent or aid in clearing chronic bacterial infection by delivering effective doses of antibiotics to the area of interest and can be engineered to simultaneously aid in tissue regeneration. This review will provide a background on bacterial infection and current therapies as well as current and prospective implantable DDDs, with a particular emphasis on local DDDs to combat bacterial osteomyelitis.

Skull base osteomyelitis in patients with head and neck cancer: Diagnosis, management, and outcomes in a case series of 23 patients

BACKGROUND

Skull base osteomyelitis (SBO) is an infection of the central cranial bones, most commonly resulting from contiguous spread of infection from adjacent head and neck structures. SBO is a well-recognized complication of treatment of head and neck cancer (HNC) that results in significant morbidity.

METHODS

We conducted a retrospective chart review of HNC patients diagnosed with SBO.

RESULTS

SBO was commonly diagnosed with nasal endoscopy showing mucosal breakdown between the naso/oropharynx and skull base and with characteristic changes on CT/MRI. Culture data were often polymicrobial, inclusive of naso/oropharyngeal flora, but half of the patients additionally had antibiotic-resistant or atypical pathogens. The mean duration of antimicrobial therapy was 117 +/- 94 days. Recurrent SBO was found in half of the patients, associated with Pseudomonas aeruginosa and with persistent defects in the mucosa abutting the skull base.

CONCLUSIONS

Diagnosis and management of SBO in HNC patients are challenging. Recommendations to aid in clinical care are proposed.

LEVEL OF EVIDENCE

4, case series.

Advances in Copper-Based Biomaterials With Antibacterial and Osteogenic Properties for Bone Tissue Engineering

Treating bone defects coupled with pathogen infections poses a formidable challenge to clinical medicine. Thus, there is an urgent need to develop orthopedic implants that provide excellent antibacterial and osteogenic properties. Of the various types, copper-based biomaterials capable of both regenerating bone and fighting infections are an effective therapeutic strategy for bone tissue engineering and therefore have attracted significant research interest. This review examines the advantages of copper-based biomaterials for biological functions and introduces these materials’ antibacterial mechanisms. We summarize current knowledge about the application of copper-based biomaterials with antimicrobial and osteogenic properties in the prevention and treatment of bone infection and discuss their potential uses in the field of orthopedics. By examining both broad and in-depth research, this review functions as a practical guide to developing copper-based biomaterials and offers directions for possible future work.

Investigating the Growth of Pseudomonas aeruginosa and Its Influence on Osteolysis in Human Bone: An In Vitro Study

Background

Isolation of the causal microorganisms in osteomyelitis presents a major challenge for treating clinicians. Several methods have been proposed to rapidly and accurately identify microorganisms. There has been an increasing interest in using Raman spectroscopy in the field of microbial detection and characterisation. This paper explores the use of Raman spectroscopy identification as one of the most difficult-to-isolate microorganisms causing osteomyelitis.

Methods and results

Fresh healthy human bone samples were collected from patients undergoing a total knee replacement. These samples were then inoculated with fresh overnight Pseudomonas aeruginosa (PAO) cultures. Bacteria growth and bone ultrastructural changes were monitored over a period of 6 weeks. The experiment demonstrated ultrastructural bony destruction caused by osteolytic PAO secretions. Raman-specific spectral signatures related to the cellular membranes of PAO structures were spotted indicating survival of bacteria on the bone surface.

Conclusion

This study showed the promising ability of Raman spectroscopy to identify the presence of bacteria on the surface of inoculated bone samples over time. It was able to detect the osteolytic activity of the bacteria as well as ultrastructure specific to PAO virulence. This method may have a role as an aid to existing diagnostic methods for fast and accurate bacterial identification in bone infection.

How to cite this article

Al Ghaithi A, Al Bimani A, Al Maskari S. Investigating the Growth of Pseudomonas aeruginosa and Its Influence on Osteolysis in Human Bone: An In Vitro Study. Strategies Trauma Limb Reconstr 2021;16(3):127–131.

Surgery's role in contemporary osteoarticular infection management

The treatment paradigm for osteoarticular infections (OAIs) has changed drastically over the past 80 years, from the advent of penicillin to the use of broad-spectrum antibiotics. Before these drugs, surgery was the only available treatment for OAIs; today, antibiotic therapy is considered the primary response to them. As a result, surgical treatment of OAIs is thus far more rarely indicated, sometimes even considered outdated and obsolete. However, long experience has taught us that many OAI contexts can still benefit from surgical management, constituting an essential complement to medical treatment. The present article seeks to contextualize this discussion by providing a chronological review of the surgical treatments used in cases of OAI and describing the quality of evidence supporting their rehabilitation in well-established situations.

Current and novel diagnostics for orthopedic implant biofilm infections: a review

Biofilm infections involving orthopedic implants are a global problem. They contribute to severe complications and mortality, as well as increased use of antibiotic treatments and development of antibiotic-resistant microorganisms. More than 1 million hip and knee arthroplasties are performed each year in the United States. These hard-to-treat infections lead to patient distress, increased morbidity, and high financial costs to both patients and healthcare systems. There is a need to improve the diagnosis of such biofilm infections to allow for earlier detection and treatment. Current diagnostics rely on clinical signs for infections such as loss of function, fever, rubor, patient history of the predisposing condition, persisting infection, failure of antibiotic treatment, and documentation of antibiotic failure. Below, we present a framework which outlines the data gaps in the conventional laboratory techniques used in clinical diagnostics; we also discuss promising novel diagnostic methods which are currently used solely in research. It is critical to assess these novel infection diagnostic techniques and address the data gaps and clinical hesitance preventing application in a clinical setting. Additionally, the combination of conventional and novel diagnostic technologies would streamline the diagnostic process of biofilm infections associated with orthopedic implants.

Recent advances in the local antibiotics delivery systems for management of osteomyelitis

Chronic osteomyelitis is a challenging disease due to its serious rates of mortality and morbidity while the currently available treatment strategies are suboptimal. In contrast to the adopted systemic treatment approaches after surgical debridement in chronic osteomyelitis, local drug delivery systems are receiving great attention in the recent decades. Local drug delivery systems using special carriers have the pros of enhancing the feasibility of penetration of antimicrobial agents to bone tissues, providing sustained release and localized concentrations of the antimicrobial agents in the infected area while avoiding the systemic side effects and toxicity. Most important, the incorporation of osteoinductive and osteoconductive materials in these systems assists bones proliferation and differentiation, hence the generation of new bone materials is enhanced. Some of these systems can also provide mechanical support for the long bones during the healing process. Most important, if the local systems are designed to be injectable to the affected site and biodegradable, they will reduce the level of invasion required for implantation and can win the patients’ compliance and reduce the healing period. They will also allow multiple injections during the course of therapy to guard against the side effect of the long-term systemic therapy. The current review presents different available approaches for delivering antimicrobial agents for the treatment of osteomyelitis focusing on the recent advances in researches for local delivery of antibiotics.

HIGHLIGHTS

Chronic osteomyelitis is a challenging disease due to its serious mortality and morbidity rates and limited effective treatment options.

Local drug delivery systems are receiving great attention in the recent decades.

Osteoinductive and osteoconductive materials in the local systems assists bones proliferation and differentiation

Local systems can be designed to provide mechanical support for the long bones during the healing process.

Designing the local system to be injectable to the affected site and biodegradable will reduces the level of invasion and win the patients’ compliance.

Treatment of postoperative tibial chronic osteomyelitis using bone transport techniques; an observational study

PURPOSE

Postoperative Tibial chronic osteomyelitis is one of the most challenging orthopaedic conditions especially when extensive, the anatomy of subcutaneous anteromedial part of the tibia with less soft tissue coverage complicates the situation. The extent of infected tibial part varies in size and duration from one patient to another. We report our experience using Bifocal and Monofocal bone transport techniques with regard to clinical outcome, recurrence of infection and re-fracture rate.

METHODS

This is a retrospective observational review of 49 patients with postoperative Tibial chronic osteomyelitis which were treated using either Bifocal distraction compression BFDCO technique group I (31 patients) or Monofocal compression osteosynthesis MFCO technique Group II (18 patients). The average age of the patients was (41.6 ± 13.1 years), (range: 17-67 years). Leg length discrepancy was measured in 33 (58.9%) patients with an average of (1.4 ± 1.7 cm). Contracture of the ankle joint and equinus deformity were detected in 36 (64.3%) patients. Pre and Post-operative radiography together with Modified Irzhansky A.A et al. leg functional assessment system were used to assess the functional outcome.

RESULTS

The time spent in the Ilizarov fixator (External Fixation Index) in the first group was (142 ± 72 days) and in the second group was (75 ± 54 days). The infection recurred in 2 patients (6%) in group I and in 5 patients (28%) in group II. Lack of consolidation or re-fracture within 6 months after the dismantling of the apparatus was detected in 6 patients (19.5%) in group I and in 5 patients (27.8%) in group II. Lack of consolidation or re-fracture within 6 months after dismantling of the apparatus in group I was detected in 6 patients (19.5%) in group I and in 5 patients (27.8%) in Group II. The average functional state score (AFSS) in the first group was (12.45 ± 2.41) on admission and increased to (16.16 ± 2.99) on the final follow-up which corresponded to a "good" result. In the second group II the AFSS was (12.11 ± 2.22) on admission and increased to (15.06 ± 2.88) at the final follow-up which corresponded to a "satisfactory" result.

CONCLUSION

Treatment of Tibial chronic osteomyelitis using either Bifocal or Monofocal bone transport is an effective method. However our results have demonstrated better functional outcome and less infection recurrence and re-fracture rates when using the Bifocal distraction compression technique (BFDCO).

Characterization of an osteomyelitis case caused by dalbavancin, ceftaroline, and vancomycin non-susceptible methicillin-resistant Staphylococcus aureus

We report a case of osteomyelitis due to methicillin-resistant Staphylococcus aureus (MRSA) that is also non-susceptible to vancomycin, dalbavancin, ceftaroline, and ceftobiprole, in the absence of exposure to the latter three antibiotics. It was isolated from a patient with a 26-year history of cranial surgeries and episodes of osteomyelitis. Whole-genome sequencing was performed. It was found to belong to ST247 and the mecA gene was detected within the SSCmec type I (1B) gene cassette that lacked the E447K mutation known to produce resistance to ceftobiprole and ceftaroline. However, mutations in other genes related to resistance to these antibiotics were found.

Intramedullary Antibiotic Depot Does Not Preclude Successful Intramedullary Lengthening or Compression

SUMMARY

The challenging problem of long bone infection and limb length difference cannot be addressed using only an antibiotic-coated nonmagnetic static nail. The combined use of resorbable calcium sulfate and magnetic lengthening nails offers a possible solution to this dilemma, as well as for infected nonunions that require compression. We present a combined technique to treat or prevent infection using femoral or tibial intramedullary antibiotic delivery with an absorbable calcium sulfate depot and concomitant internal lengthening or compression using a nail. Adequate débridement is required in cases of established infection and is a prerequisite for this technique.

Antibiotic-loaded amphora-shaped pores on a titanium implant surface enhance osteointegration and prevent infections

Artificial prostheses for joint replacement are indispensable in orthopedic surgery. Unfortunately, the implanted surface is attractive to not only host cells but also bacteria. To enable better osteointegration, a mechanically stable porous structure was created on a titanium surface using laser treatment and metallic silver particles were embedded in a hydrophilic titanium oxide layer on top. The laser structuring resulted in unique amphora-shaped pores. Due to their hydrophilic surface conditions and capillary forces, the pores can be loaded preoperative with the antibiotic of choice/need, such as gentamicin. Cytotoxicity and differentiation assays with primary human osteoblast-like cells revealed no negative effect of the surface modification with or without gentamicin loading. An in vivo biocompatibility study showed significantly enhanced osteointegration as measured by push-out testing and histomorphometry 56 days after the implantation of the K-wires into rat femora. Using a S. aureus infection model, the porous, silver-coated K-wires slightly reduced the signs of bone destruction, while the wires were still colonized after 28 days. Loading the amphora-shaped pores with gentamicin significantly reduced the histopathological signs of bone destruction and no bacteria were detected on the wires. Taken together, this novel surface modification can be applied to new or established orthopedic implants. It enables preoperative loading with the antibiotic of choice/need without further equipment or post-coating, and supports osteointegration without a negative effect of the released dug, such as gentamicin.

Contemporary clinical isolates of Staphylococcus aureus from pediatric osteomyelitis patients display unique characteristics in a mouse model of hematogenous osteomyelitis

Osteomyelitis can result from the direct inoculation of pathogens into bone during injury or surgery, or from spread via the bloodstream, a condition called hematogenous osteomyelitis (HOM). HOM disproportionally affects children, and more than half of cases are caused by Staphylococcus (S.) aureus. Laboratory models of osteomyelitis mostly utilize direct injection of bacteria into the bone or the implantation of foreign material, and therefore do not directly interrogate the pathogenesis of pediatric hematogenous osteomyelitis. In this study, we inoculated mice intravenously and characterized resultant musculoskeletal infections using two strains isolated from adults (USA300-LAC and NRS384) and five new methicillin-resistant S. aureus isolates from pediatric osteomyelitis patients. All strains were capable of creating stable infections over five weeks, although the incidence varied. Micro-computed tomography (microCT) analysis demonstrated decreases in trabecular bone volume fraction but little effect on bone cortices. Histologic assessment revealed differences in the precise focus of musculoskeletal infection, with varying mixtures of bone-centered osteomyelitis and joint-centered septic arthritis. Whole genome sequencing of three new isolates demonstrated distinct strains, two within the USA300 lineage and one USA100 isolate. Interestingly, this USA100 isolate showed a distinct predilection for septic arthritis, compared to the other isolates tested, including NRS384 and LAC, which more frequently led to osteomyelitis or mixed bone and joint infections. Collectively, these data outline the feasibility of using pediatric osteomyelitis clinical isolates to study the pathogenesis of HOM in murine models and lay the groundwork for future studies investigating strain-dependent differences in musculoskeletal infection.

Real-World Clinical Use and Outcomes of Telavancin for the Treatment of Bone and Joint Infections: Results from the Telavancin Observational Use Registry (TOUR™)

Background

Additional antibiotic options are needed to treat bone and joint infections caused by penicillin-resistant Gram-positive pathogens.

Objective

This subanalysis of the Telavancin Observational Use Registry (TOUR™) aimed to record real-world telavancin usage patterns in patients with bone and joint infections treated with telavancin.

Methods

TOUR was a multicenter observational-use registry study conducted at 45 US sites between January 2015 and March 2017. Patient characteristics, infection type, infecting pathogen(s), previous treatment, telavancin dosing and duration, clinical response, and adverse event data were collected by retrospective medical chart reviews. As such, inclusion/exclusion criteria were limited, and any patient receiving at least one dose of telavancin at the discretion of the treating physician was eligible. Patients were assessed as either positive clinical response, failed treatment, or indeterminate outcome.

Results

Of the 1063 patients enrolled in TOUR, 27.4% (291/1063) were patients with bone and joint infections including osteomyelitis (with or without prosthetic material), acute septic arthritis, and prosthetic joint infections. Most of these patients had osteomyelitis without prosthetic material (191/291; 66.0%). Among patients assessed at the end of treatment, 211/268 (78.7%) achieved a positive clinical response, 26/268 (9.7%) failed treatment, and 31/268 (11.6%) had an indeterminate outcome. The most frequent pathogen was methicillin-resistant Staphylococcus aureus (110/291; 37.8%). The median (interquartile range [IQR as Q1, Q3]) telavancin dose was 750.0 mg (IQR, 750, 750 mg) or 8.2 mg/kg (IQR, 6.8, 9.7 mg/kg) administered for a median of 26 days (IQR, 12, 42 days). These assessments were recorded in the registry ≥ 30 days after the last dose of telavancin was administered.

Conclusions

Real-world data from the TOUR study show that clinicians are using once-daily telavancin with positive clinical outcomes for the treatment of bone and joint infections caused by Gram-positive pathogens.

Clinical Trial Registration

This trial was registered with ClinicalTrials.gov (NCT02288234) on 11 November, 2014.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40801-021-00255-6.

Accuracy of Tissue and Sonication Fluid Sampling for the Diagnosis of Fracture-Related Infection: Diagnostic Meta-Analysis

Evidence shows that tissue sample culturing is the gold standard approach for diagnosing fracture-related infection (FRI). Sonication fluid sampling has also been reported to be efficacious and superior to tissue sample culturing with prosthetic joint infection. However, data from the current literature are not enough to validate this hypothesis for FRI. We conducted a meta-analysis to validate the diagnostic accuracy of tissue sample culturing and sonication fluid aspiration and to find which one is superior to the other. An extensive search through the relevant databases was conducted to obtain all the relevant studies. We have included 13 relevant studies, including nine retrospective cohorts and four prospective ones. The overall pooled estimates of sensitivity, specificity, and diagnostic odds ratio (DOR) of tissue sampling culture in diagnosing fracture-related infections were 98% (95% CI, 92% to 99%), 38% (95% CI, 23% to 56%), and 25 (4 to 154), respectively. The overall pooled estimates of sensitivity, specificity, and DOR of sonication fluid sample culture in diagnosing fracture-related infections were 86% (95% CI, 79% to 92%), 98% (95% CI, 93% to 100%), and 353 (78 to 1598), respectively. No significant risk of bias was found regarding the sensitivity and specificity among studies investigating both modalities, however, significant heterogeneity was noticed. Sonication fluid sampling can be used to confirm FRI while tissue sampling can be used to exclude it and both modalities should be combined for obtaining the most accurate outcome.

Copper-Doped Biphasic Calcium Phosphate Powders: Dopant Release, Cytotoxicity and Antibacterial Properties

Cytotoxicity and antibacterial properties associated with the dopant release of Cu-doped Biphasic Calcium Phosphate (BCP) powders, mainly composed of hydroxyapatite mixed with β-tricalcium phosphate powders, were investigated. Twelve BCP ceramics were synthesized at three different sintering temperatures (600 °C, 900 °C and 1200 °C) and four copper doping rates (x = 0.0, 0.05, 0.10 and 0.20, corresponding to the stoichiometric amount of copper in Ca₁₀Cu_x(PO₄)₆(OH)_2-2xO_2x). Cytotoxicity assessments of Cu-doped BCP powders, using MTT assay with human-Mesenchymal Stem Cells (h-MSCs), indicated no cytotoxicity and the release of less than 12 ppm of copper into the biological medium. The antibacterial activity of the powders was determined against both Gram-positive (methicillin-sensitive (MS) and methicillin resistant (MR) Staphylococcus aureus) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria. The Cu-doped biomaterials exhibited a strong antibacterial activity against MSSA, MRSA and E. coli, releasing approximatively 2.5 ppm after 24 h, whereas 10 ppm were required to induce an antibacterial effect against P. aeruginosa. This study also demonstrated that the culture medium used during experiments can directly impact the antibacterial effect observed; only 4 ppm of Cu²⁺ were effective for killing all the bacteria in a 1:500 diluted TS medium, whereas 20 ppm were necessary to achieve the same result in a rich, non-diluted standard marrow cell culture medium.