Treatment algorithms for chronic osteomyelitis

A comprehensive review of pathology and treatment of staphylococcus aureus osteomyelitis

Osteomyelitis (OM) is an inflammation of the bone and bone marrow triggered by infectious pathogens which may induce progressive bone destruction. The majority of OM cases, especially the chronic OM cases, are induced by the most prevalent and devastating pathogen Staphylococcus aureus (S. aureus), partially due to its resistance mechanisms against the immune system and antibiotic therapies. Regarding the high rate of morbidity and recurrence in patients, it is pivotal to elucidate underlying mechanisms that how S. aureus enter and survive in hosts. The accumulated discoveries have identified multiple distinct strategies associated with chronicity and recurrence include biofilm development, small colony variants (SCVs), staphylococcus abscess communities (SACs), the osteocyte lacuno-canalicular network invasion (OLCN) of cortical bones, and S. aureus protein A (SpA). Unfortunately, little clinical progress has been achieved for the diagnosis and therapeutic treatment for OM patients, indicating that numerous questions remain to be solved. Therefore, we still have a long way to obtain the clear elucidation of the host-pathogen interactions which could be applied for clinical treatment of OM. In this review, we provide insights of current knowledge about how S. aureus evades immune eradication and remains persistent in hosts with recent discoveries. The common and novel treatment strategies for OM are also described. The purpose of this review is to have in-dept understanding of S. aureus OM and bring new perspectives to therapeutic fields which may be translated to the clinic.

Refractory sphenoid wing osteomyelitis as a complication of orbital decompression

Osteomyelitis of the sphenoid wing is a rare clinical entity that can result in significant morbidity due to cranio-orbital infection. This entity has never previously been described as a complication of orbital decompression. An elderly patient developed relapsing orbital cellulitis and cranio-orbital abscesses following orbital decompression. Multiple attempts at incision and drainage with extended antibiotic therapy failed to eliminate the infection. The patient's clinical course was indicative of sphenoid osteomyelitis at the prior decompression site. A combined craniotomy-orbitotomy with debridement of the involved portion of the sphenoid resulted in resolution of the patient's clinical symptoms. Surgeons should be aware of the possibility of this rare infection following any surgery in which bone is structurally modified or removed, including orbital decompression.

Histopathological Osteomyelitis Evaluation Score (HOES): Pioneering precision for diagnosing jaw osteomyelitis

Background

Osteomyelitis is an inflammatory condition of bone that may arise in response to a foci of infection. A multidisciplinary approach is necessary between the clinician, pathologist, and radiologist to give an early diagnosis for initiating early treatment to prevent lifelong debility.

Objective

The objectives of this study were to analyze the applicability of Histopathological Osteomyelitis Evaluation Score (HOES) in diagnosing different stages of jaw osteomyelitis and to compare the HOES method with preoperative and conventional histopathological diagnosis.

Method

In this retrospective study, 40 slides of preoperatively diagnosed cases of osteomyelitis were evaluated semiquantitatively using HOES criteria for acute (A1, A2, and A3) and chronic (C1 and C2) cases based on histopathological changes in the bone, soft tissue, and inflammatory infiltrate. The results obtained were compared and correlated to preoperative diagnosis and conventional histopathological diagnosis by using Chi-square and Spearman's correlation coefficient.

Result

Out of 40 cases, 26 (65%) were men and 14 (35%) were women, with a mean age of 45.1 years (range: 7 to 70 years). The frequency of occurrence was found to be 68% in mandible and 32% in maxilla. Significant association was observed between HOES and conventional histopathological diagnosis (χ 2 = 15.91, P < 0.001), as well as HOES and preoperative diagnosis (χ 2 = 12.69, P < 0.005). The results of Spearman's correlation revealed 50% correlation of HOES with conventional histopathological diagnosis and 43% with preoperative diagnosis.

Conclusion

HOES serves as a systematic and precise method for classification and differentiation of different stages of osteomyelitis which aids in the stratification of patients for their treatment needs, preventing and halting the progression of disease at an early stage.

Treatment of chronic osteomyelitis with gradient release of DGEA and vancomycin hydrogel-microsphere system and its mechanism

In recent years, the treatment of chronic osteomyelitis mediated by biodegradable polymer platforms has received increasing attention. This paper reports an advanced drug delivery system, vancomycin (VA) and DGEA loaded microspheres embedded in injectable thermosensitive polypeptide hydrogels (i.e., hydrogel-microsphere (Gel-MP) construct), for continuous release of drugs with different mechanisms and more comprehensive treatment of chronic osteomyelitis. The Gel-MP construct exhibits continuous biodegradability and excellent biocompatibility. Microspheres (MP) are wrapped inside Gel. With the degradation of Gel, VA and MP are released from them, VA released with faster degradation speed, achieving a potent antibacterial effect and effectively controlling infection. Due to the slower degradation rate of MP compared to Gel, subsequently, DGEA is released from MP to induce bone formation and produce the effect of filling bone defects. Compared with other formulations, the in vivo combinational treatment of Gel/VA-MP/DGEA can simultaneously balance antibacterial and osteogenic effects. More importantly, local sustained-release drug delivery systems can significantly mitigate the systemic toxicity of drugs. Therefore, the injection local sequential drug delivery system has broad prospects in the clinical application of treating chronic osteomyelitis.

Delayed pathologic tibial fracture with chronic osteomyelitis after fibula free flap

The reported donor site morbidity of the fibula free flap (FFF) is low; however, several uncommon complications have been reported with tibia fracture rarely being reported. We present a case of a pathological tibial fracture in the setting of chronic osteomyelitis after FFF. A 54-year-old female presented with a benign fibro-osseous lesion of the right mandible and was treated with mandibulectomy and reconstructed with a left FFF. Approximately 1 year following surgery, the patient presented to the emergency department. Imaging showed a pathological fracture of the distal third of the tibial shaft with persistent erythema and cellulitis of the lateral prior graft harvest site without signs of systemic infection. She was taken to the operating room for irrigation and debridement with culture and biopsy as well as external fixation of the tibial fracture. Intraoperative biopsy and culture demonstrated fracture site change with callus formation and negative culture. The patient was discharged on 6 weeks of IV vancomycin and ceftriaxone. In conclusion, tibial fracture following FFF is an uncommon complication, yet it can be exacerbated by chronic osteomyelitis. This report highlights the importance of close observation and comprehensive wound care of donor sites after free flap harvest for head and neck reconstruction.

Ilizarov External Fixator Versus Orthofix LRS in Management of Femoral Osteomyelitis: A Propensity Score Matched Analysis

Purpose

Treatment of osteomyelitis (OM) is challenging. Ilizarov bone transport is a commonly used technique for management of OM. The recently introduced limb reconstruction system (LRS) has been effectively used for management of OM. It was suggested to be easier in use and less invasive. The present retrospective study aimed to compare LRS and Ilizarov bone transport in management of femoral OM using a propensity score matched analysis.

Methods

The present retrospective study included 80 consecutive patients with femoral OM. The studied patients were managed either using Ilizarov external fixator (n = 40) or Orthofix LRS (n = 40). The clinical outcome measurements included union time, limb length discrepancy, additional operative procedures, refracture and infection.

Results

Patients in the LRS group were exposed to significantly higher frequency of bone transport (30.0 versus 15.0%) and lower frequency of acute compression and lengthening (10.0 versus 32.5%). Patients in Ilizarov group had significantly higher frequency of tobramycin pellets as compared to their counterparts. The studied groups were comparable regarding the operative complications including pin-tract infection, non-union at docking site and refracture. Patients in the Ilizarov had significantly shorter time to union (8.2 ± 3.2 versus 11.0 ± 5.6 months, p = 0.012). No statistically significant differences were found between the studied groups regarding the quality-of-life domains.

Conclusions

Use of Ilizarov external fixator and Orthofix LRS devices proved to be effective and reliable. Their influences on patients' quality appear to be comparable.

Gelatin-based nanoparticles and antibiotics: a new therapeutic approach for osteomyelitis?

The result of infection of bone with microorganisms is osteomyelitis and septic arthritis. Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for most of its cases (more than 50%). Since MRSA is resistant to many treatments, it is accompanied by high costs and numerous complications, necessitating more effective new treatments. Recently, development of gelatin nanoparticles have attracted the attention of scientists of biomedicine to itself, and have been utilized as a delivery vehicle for antibiotics because of their biocompatibility, biodegradability, and cost-effectiveness. Promising results have been reported with gelatin modification and combinations with chemical agents. Although these findings have been suggested that gelatin has the potential to be a suitable option for continuous release of antibiotics in osteomyelitis and septic arthritis treatment, they still have not become routine in clinical practices. The most deliver antibiotic using gelatin-derived composites is vancomycin which is showed the good efficacy. To date, a number of pre-clinical studies evaluated the utility of gelatin-based composites in the management of osteomyelitis. Gelatin-based composites were found to have satisfactory performance in the control of infection, as well as the promotion of bone defect repair in chronic osteomyelitis models. This review summarized the available evidence which provides a new insight into gelatin-derived composites with controlled release of antibiotics.

Recurrent skin opening induced by chronic sternal osteomyelitis caused by a bite wound in a cat: A case report

BACKGROUND

Chronic sternal osteomyelitis is a rare condition in felines, with limited reported cases to date.

OBJECTIVES

We report the case of a 2-year-old castrated male, domestic shorthair cat, weighing 4.68 kg, that presented with skin openings every 3-4 months, despite skin debridement and reconstruction.

METHODS

A subcutaneous dead space larger than the skin defect was detected. Haematological analysis revealed elevated levels of inflammatory markers. Thoracic radiography revealed sternal deformation and suspected osteomyelitis. Computed tomography revealed a fistula extending from the third to the fourth sternebrae.

RESULTS

Bone and soft tissue debridement and abscess flushing were performed along with long-term antibiotic therapy. The cat remained recurrence-free throughout an 18-month post-surgery follow-up period.

CONCLUSION

To the best of our knowledge, this is the first report of chronic osteomyelitis occurring in a cat's sternebrae and represents the first successful case of its treatment. This case showcases the potential for improved treatment outcomes in similar cases. Understanding and successful treatment of such cases can pave the way for better management of feline osteomyelitis.

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.

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.

[Diagnostic and therapeutic work-up of infected tibial nonunion]

BACKGROUND

The failure of bone fracture healing is one of the major complications of fracture treatment, especially of the tibia due to its limited soft tissue coverage and high rate of open injuries. Although implant development is constantly progressing and modern surgical techniques are continuously improving, infected tibial nonunion plays a decisive role in terms of its variable clinical presentation.

OBJECTIVE

This article provides guidelines for the successful surgical treatment of infected tibial nonunion.

MATERIAL AND METHOD

Strategies are presented to identify infection as a cause of failure of fracture healing and to achieve infection and bone healing.

RESULTS

A significant amount of tibial nonunions primarily thought to be aseptic ultimately turn out to be infected nonunions.

CONCLUSION

The treatment of infected tibial nonunion requires extensive clinical, radiological and laboratory diagnostics as well as a profound biomechanical and biological understanding of the bone situation. This is the only way to achieve rapid osseous healing with as few revision interventions as possible.

A Rare Case of Fungal Osteomyelitis of the Distal Tibia in a Pediatric Patient

Staphylococcus aureus infection is the most common cause of osteomyelitis. Over 100,000 fungal species have been described; only 150 are pathogenic to humans. These opportunistic infections frequently enter the body due to a decrease in host defense or through an invasive gateway, such as a dental extraction or skin discontinuity due to trauma. Symptoms and radiological examination often mimic those of other etiologies, which can lead to substantial delays in treatment. Our case is a 13-year-old healthy boy with no history of immune incompetency who presented to us with complaints of pain and swelling over his left ankle and leg with an on-and-off history of fever for 15 days. Based on his history and examination, he is diagnosed as having sub-acute osteomyelitis of the distal tibia with septic arthritis. The bacterial culture has no growth; however, the potassium hydroxide mount came positive for fungal elements having hyphae and pseudohyphae, and the fungal culture came positive for Candida. Management of fungal infections is challenging as they have infrequent involvement in bones. Fungal osteomyelitis is considered a rare entity in the literature, and the current case is studied for the management and diagnosis of a rare variant of osteomyelitis in the pediatric population. The treatment guidelines vary based on the identified organism and the duration of treatment. Debridement of fungal osteomyelitis or septic arthritis includes removing sinus tracts, evaluation for squamous cell carcinoma, bony and soft-tissue debridement, and antibiotic or antifungal bead placement. The spectrum of osteomyelitis ranges from Staphylococcus aureus organisms to tumors; therefore, it is necessary to investigate every spectrum of the disease, and fungal infections should be considered differential even though they are a rare entity. Early diagnosis, surgical debridement, and proper antifungal treatment based on fungal species lead to better clinical outcomes and results.

Management of Refractory Post-operative Osteomyelitis and Discitis: A Case Report

Vertebral osteomyelitis/discitis is a relatively rare disease but is a known potential complication of spinal surgical intervention. In general, the first-line treatment for this condition is targeted antibiotic therapy with surgical intervention only utilized in refractory cases with evidence of extensive damage, structural instability, or abscess formation. However, surgical best practices have not been established for osteomyelitis, including indications for anterior lateral interbody fusion (ALIF), posterior lateral interbody fusion (PLIF), or direct lateral interbody fusion (DLIF). This case provides a discussion of the indications that led to a direct lateral approach in the setting of refractory osteomyelitis/discitis, supporting factors that led to its success, and the efficacy of utilizing intraoperative neuromonitoring in cases of infection.

In situ lipidomics of Staphylococcus aureus osteomyelitis using imaging mass spectrometry

Osteomyelitis occurs when Staphylococcus aureus invades the bone microenvironment, resulting in a bone marrow abscess with a spatially defined architecture of cells and biomolecules. Imaging mass spectrometry and microscopy are invaluable tools that can be employed to interrogate the lipidome of S. aureus-infected murine femurs to reveal metabolic and signaling consequences of infection. Here, nearly 250 lipids were spatially mapped to healthy and infection-associated morphological features throughout the femur, establishing composition profiles for tissue types. Ether lipids and arachidonoyl lipids were significantly altered between cells and tissue structures in abscesses, suggesting their roles in abscess formation and inflammatory signaling. Sterols, triglycerides, bis(monoacylglycero)phosphates, and gangliosides possessed ring-like distributions throughout the abscess, indicating dysregulated lipid metabolism in a subpopulation of leukocytes that cannot be discerned with traditional microscopy. These data provide chemical insight into the signaling function and metabolism of cells in the fibrotic border of abscesses, likely characteristic of lipid-laden macrophages.

Isolated cervical Cutibacterium acnes osteomyelitis in a patient with no primary source of infection - A case report and review of the literature

Background

Cervical vertebral osteomyelitis (CVO) is a rare pathology that leads to progressive osseous degradation and eventual loss of bone putting the patient at risk of devastating neurological injury in the event of bony collapse or instability. Cutibacterium acnes formerly called Propionibacterium acnes is rare, but within the last two decades has been an increasingly reported cause of osteomyelitis. The majority of C. acnes vertebral osteomyelitis cases have been reported in patients with a history of prior invasive procedures where direct contamination at the time of procedure was suspected as the underlying etiology.

Case Description

We report a unique case of an otherwise healthy 39-year-old male with no prior history of invasive procedures who presented with CVO secondary to C. acnes. He underwent surgical debridement and fusion in conjunction with antibiotic treatment. The patient recovered well and a 2-year follow-up with serial imaging showed no evidence of disease recurrence.

Conclusion

C. acnes is an under-recognized and under-reported etiology of spine infections. Clinicians should be aware of the pathological potential and atypical presentation of C. acnes vertebral osteomyelitis.

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.

Diagnosis and treatment of chronic osteomyelitis based on nanomaterials

Chronic osteomyelitis is a painful and serious disease caused by infected surgical prostheses or infected fractures. Traditional treatment includes surgical debridement followed by prolonged systemic antibiotics. However, excessive antibiotic use has been inducing rapid emergence of antibiotic-resistant bacteria worldwide. Additionally, it is difficult for antibiotics to penetrate internal sites of infection such as bone, thus limiting their efficacy. New approaches to treat chronic osteomyelitis remain a major challenge for orthopedic surgeons. Luckily, the development of nanotechnology has brought new antimicrobial options with high specificity to infection sites, offering a possible way to address these challenges. Substantial progress has been made in constructing antibacterial nanomaterials for treatment of chronic osteomyelitis. Here, we review some current strategies for treatment of chronic osteomyelitis and their underlying mechanisms.

[Application of homemade antibiotic bone cement rod in tibial screw canal osteomyelitis]

Objective

To investigate the effectiveness of homemade antibiotic bone cement rod in the treatment of tibial screw canal osteomyelitis by Masquelet technique.

Methods

A clinical data of 52 patients with tibial screw canal osteomyelitis met the criteria between October 2019 and September 2020 was retrospectively analyzed. There were 28 males and 24 females, with an average age of 38.6 years (mean, 23-62 years). The tibial fractures were treated with internal fixation in 38 cases and external fixation in 14 cases. The duration of osteomyelitis was 6 months to 20 years with a median of 2.3 years. The bacterial culture of wound secretions showed 47 positive cases, of which 36 cases were infected with single bacteria and 11 cases were infected with mixed bacteria. After thorough debridement and removal of internal and external fixation devices, the locking plate was used to fixed the bone defect. The tibial screw canal was filled with the antibiotic bone cement rod. The sensitive antibiotics were given after operation and the 2nd stage treatment was performed after infection control. The antibiotic cement rod was removed and the bone grafting in the induced membrane was performed. After operation, the clinical manifestations, wound, inflammatory indexes, and X-ray films were monitored dynamically, and the postoperative bone infection control and bone graft healing were evaluated.

Results

Both patients successfully completed the two stages of treatments. All patients were followed up after the 2nd stage treatment. The follow-up time was 11 to 25 months (mean, 18.3 months). One patient had poor wound healing and the wound healed after enhanced dressing change. X-ray film showed that the bone grafting in the bone defect healed and the healing time was 3-6 months, with an average of 4.5 months. The patient had no recurrence of infection during the follow-up period.

Conclusion

For the tibial screw canal osteomyelitis, the homemade antibiotic bone cement rod can reduce the recurrence rate of infection and obtain a good effectiveness, and has the advantages of simple operation and less postoperative complications.

Current research progress of local drug delivery systems based on biodegradable polymers in treating chronic osteomyelitis

Chronic osteomyelitis is one of the most challenging diseases in orthopedic treatment. It is usually treated with intravenous antibiotics and debridement in clinical practice, which also brings systemic drug side effects and bone defects. The local drug delivery system of antibiotics has the characteristics of targeted slow release to the lesion site, replacing systemic antibiotics and reducing the toxic and side effects of drugs. It can also increase the local drug concentration, achieve sound bacteriostatic effects, and promote bone healing and formation. Currently, PMMA beads are used in treating chronic osteomyelitis at home and abroad, but the chain beads need to be removed after a second operation, inconveniences patients. Biodegradable materials have been extensively studied as optimal options for antibiotic encapsulation and delivery, bringing new hope for treating chronic osteomyelitis. This article reviews the research progress of local drug delivery systems based on biodegradable polymers, including natural and synthetic ones, in treating chronic osteomyelitis.

Risk Factors for Postoperative Osteomyelitis among Patients after Bone Fracture: A Matched Case-Control Study

The healthcare burden of osteomyelitis is increasing. Postoperative and posttraumatic osteomyelitis account for 80% of all cases of osteomyelitis. The aim of this study was to find risk factors for postoperative osteomyelitis in Kazakhstan. We included 245 patients admitted to the National Scientific Center of Traumatology and Orthopedics from 2018 to 2020. Cases were matched with controls in a 1:4 ratio. Exact matching was performed by gender, ICD-10, and ICD-9 codes. The main variables included socio-demographics, diagnosis at admission, characteristics of fractures, comorbidities, complications, hospitalization milestones, and osteomyelitis characteristics. Descriptive analyses, along with bivariate analysis and multivariate conditional logistic regression, were performed. Open fracture (adjOR = 6.25; 95%CI 1.64−23.79), the presence of complications of initial fracture (adjOR = 3.46, 95%CI 1.13−10.56), comminuted fracture form (adjOR = 1.87; 95%CI 0.73−4.75), a positive history of diabetes or blood glucose >7 g/L (adjOR = 4.25; 95%CI 1.26−14.3), incision or wound length of more than 10 cm (adjOR = 6.53; 95%CI 1.1−38.6), additional implanted medical item (adjOR = 1.23; 95% CI 1.1−1.47), and unemployment or being retired (adjOR = 4.21; 95%CI 1.74−10.18) were found to be significant predictors of postoperative osteomyelitis. Almost all our findings are concordant with previous studies, except for the type of fracture. Different authors report conflicting results on the latter potential risk factor. Therefore, prospective studies on this issue are required.

Recent Advances in Multifunctional Hydrogels for the Treatment of Osteomyelitis

Osteomyelitis (OM), a devastating disease caused by microbial infection of bones, remains a major challenge for orthopedic surgeons. Conventional approaches for prevention and treatment of OM are unsatisfactory. Various alternative strategies have been proposed, among which, hydrogel-based strategies have demonstrated potential due to their unique properties, including loadable, implantable, injectable, printable, degradable, and responsive to stimuli. Several protocols, including different hydrogel designs, selection of antimicrobial agent, co-administration of bone morphogenetic protein 2 (BMP 2), and nanoparticles, have been shown to improve the biological properties, including antimicrobial effects, osteo-induction, and controlled drug delivery. In this review, we describe the current and future directions for designing hydrogels and their applications to improve the biological response to OM in vivo.

Local Fixation of Colistin With Fibrin Spray: An in vivo Animal Study for the Therapy of Skin and Soft Tissue Infections

Objective

Skin and soft tissue infections (SSTI) are a commonly known entity of diseases associated with difficult treatment procedures. The current gold standard when there is a rapidly progressing infection of soft tissues with a risk of sepsis is radical surgical debridement accompanied by systemic antibiotic therapy. In clinical settings, local antibiotics alone or formulated within carrier material are commonly used alongside this therapy regimen. One possibility of local antibiotic application is the fixation of colistin with fibrin glue spray. It is not yet sufficiently researched how the local antibiotic concentrations remain as high as possible over time.

Methods

We conducted an animal study including 29 male Wistar rats inducing sterile back sores reaching the muscle fascia. We sprayed only colistin, simultaneously or consecutively, with fibrin glue in different groups in order to measure the tissue concentration of the antibiotic applied locally.

Results

After liquid chromatography and quadrupole mass spectrometry analysis, it could be demonstrated that in comparison to the colistin group, tissue concentrations of colistin stayed significantly higher in the wound tissue when it was fixed with fibrin glue. This was observed in both groups, the simultaneous as well as in the consecutively fibrin glue sprayed groups after colistin application.

Conclusion

The fixation of colistin with the fibrin-glue-spray technique as a carrier for local antibiotic therapy is an easy and inexpensive method and shows promising potential for the treatment of SSTI.

Progress in diagnosis and treatment of post-traumatic osteomyelitis

Post-traumatic osteomyelitis is one of the most common disorders of bone infection, which is secondary to open fracture caused by machinery injury, traffic accident, and it is also the main manifestation in the postoperative infection of open fracture. After trauma, bacteria invade bone tissue and reproduce rapidly in large quantities, which easily leads to osteomyelitis. Patients are often complaint of pain at the affected limb, loss of function, or even amputation due to deteriorated infection, resulting in loss of labor capability and poor quality of life. Because the diagnosis and treatment are not timely and standard, the treatment for post-traumatic osteomyelitis is often delayed, resulting in the difficulty of clinical cure. It also makes patients and their families bear a serious financial burden. However, the diagnosis and treatment for this disease is difficult for orthopedic physicians. In recent years, imaging methods (such as CT and MRI) combined with immune techniques have significantly improved the diagnostic accuracy and early diagnosis ability. The application of new diagnostic technologies (such as gene chip and second-generation sequencing) also makes the diagnosis more convenient and sensitive. The novel reconstruction and repair surgery (such as Ilizarov technology and Orthofix LRS technology) provides new treatment direction for orthopedic surgeons and patients.

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.

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.

Novel calcium phosphate cement with biofilm-inhibition and platelet lysate delivery to enhance osteogenesis of encapsulated human periodontal ligament stem cells

Osteomyelitis is caused by Staphylococcus aureus (S. aureus), with associated progressive bone loss. This study developed for the first time a calcium phosphate cement (CPC) for delivery of doxycycline (DOX) and human platelet lysate (hPL) to fight against S. aureus infection and enhance the osteogenesis of human periodontal ligament stem cells (hPDLSCs). Chitosan-containing CPC scaffolds were fabricated in the absence (CPCC) or presence of DOX (CPCC+DOX). In addition, hPL was encapsulated in alginate microbeads and incorporated into CPCC+DOX (CPCC+DOX+ hPL). Flexural strength of CPCC+DOX + hPL was (5.56 ± 0.55) MPa, lower than (8.26 ± 1.6) MPa of CPCC+DOX (p < 0.05), but exceeding the reported strength of cancellous bone. CPCC+DOX and CPCC+DOX + hPL exhibited strong antibacterial activity against S. aureus, reducing biofilm CFU by 4 orders of magnitude. The hPDLSCs encapsulated in microbeads were co-cultured with the CPCs. The hPDLSCs were able to be released from the microbeads and showed a high proliferation rate, increasing by about 8 folds at 14 days for all groups. The hPL was released from the scaffold and promoted the osteogenic differentiation of hPDLSCs. ALP activity was 28.07 ± 5.15 mU/mg for CPCC+DOX + hPL, higher than 17.36 ± 2.37 mU/mg and 1.34 ± 0.37 mU/mg of CPCC+DOX and CPCC, respectively (p < 0.05). At 7 days, osteogenic genes (ALP, RUNX2, COL-1, and OPN) in CPCC+DOX + hPL were 3-10 folds those of control. The amount of hPDLSC-synthesized bone mineral with CPCC+DOX + hPL was 3.8 folds that of CPCC (p < 0.05). In summary, the novel CPC + DOX + hPL-hPDLSCs scaffold exhibited strong antibacterial activity, excellent cytocompatibility and hPDLSC osteogenic differentiation, showing a promising approach for treatment and prevention of bone infection and enhancement of bone regeneration.

Construction of Antimicrobial Material-Loaded Porous Tricalcium Phosphate Beads for Treatment of Bone Infections

Due to low success rates of antibiotic therapy in most osteomyelitis diseases, continuous efforts have been made to fabricate local delivery systems with high antimicrobial effects. Here, we reported a kind of ε-polylysine(PL)/Ag-loaded porous tricalcium phosphate (TCP) bead instead of antibiotics as local delivery systems for the treatment of Staphylococcus aureus-caused osteomyelitis. Such local delivery systems were prepared by the fabrication of porous TCP beads at first and then the loading of Ag and PL in turn into porous TCP beads via in situ Ag-doping and layer-by-layer methods. In vitro experiments demonstrated that the release of PL and Ag was controllable. Especially, the release dosage of Ag could be controlled to be less than 0.05 ppm 28 days later. The surface coating of PL improved the cytocompatibility and antibacterial activity of local delivery systems. In vivo experiments demonstrated that the Ag/PL-loaded porous TCP beads displayed strong antibacterial activity and good osteoconductivity, and the combination of Ag and PL was better than the use of single antibacterial materials to treat S. aureus-caused osteomyelitis. The implantation of Ag into the infected marrow had low toxicity because Ag has been integrated into the TCP grains, which could be absorbed in marrow. Therefore, the Ag/PL-loaded porous TCP beads presented potential for treating osteomyelitis, especially sequestrum-debrided osteomyelitis.

3D Cocultures of Osteoblasts and Staphylococcus aureus on Biomimetic Bone Scaffolds as a Tool to Investigate the Host-Pathogen Interface in Osteomyelitis

Osteomyelitis (OM) is an infectious disease of the bone primarily caused by the opportunistic pathogen Staphylococcus aureus (SA). This Gram-positive bacterium has evolved a number of strategies to evade the immune response and subvert bone homeostasis, yet the underlying mechanisms remain poorly understood. OM has been modeled in vitro to challenge pathogenetic hypotheses in controlled conditions, thus providing guidance and support to animal experimentation. In this regard, traditional 2D models of OM inherently lack the spatial complexity of bone architecture. Three-dimensional models of the disease overcome this limitation; however, they poorly reproduce composition and texture of the natural bone. Here, we developed a new 3D model of OM based on cocultures of SA and murine osteoblastic MC3T3-E1 cells on magnesium-doped hydroxyapatite/collagen I (MgHA/Col) scaffolds that closely recapitulate the bone extracellular matrix. In this model, matrix-dependent effects were observed in proliferation, gene transcription, protein expression, and cell–matrix interactions both of the osteoblastic cell line and of bacterium. Additionally, these had distinct metabolic and gene expression profiles, compared to conventional 2D settings, when grown on MgHA/Col scaffolds in separate monocultures. Our study points to MgHA/Col scaffolds as biocompatible and bioactive matrices and provides a novel and close-to-physiology tool to address the pathogenetic mechanisms of OM at the host–pathogen interface.

Preclinical models of vertebral osteomyelitis and associated infections: Current models and recommendations for study design

Spine-related infections, such as vertebral osteomyelitis, discitis, or spondylitis, are rare diseases that mostly affect adults, and are usually of hematogenous origin. The incidence of this condition has gradually risen in recent years because of increases in spine-related surgery and hospital-acquired infections, an aging population, and intravenous (IV) drug use. Spine infections are most commonly caused by Staphylococcus aureus, while other systemic infections such as tuberculosis and brucellosis can also cause spondylitis. Various animal models of vertebral osteomyelitis and associated infections have been investigated in mouse, rat, chicken, rabbit, dog, and sheep models by hematogenous and direct inoculation in surgery, each with their strengths and limitations. This review is the first of its kind to concisely analyze the various existing animal models used to reproduce clinically relevant models of infection. Spine-related infection models must address the unique anatomy of the spine, the avascular nature of its structures and tissues and the consequences of tissue destruction such as spinal cord compression. Further investigation is necessary to elucidate the specific mechanisms of host-microbe response to inform antimicrobial therapy and administration techniques in a technically demanding body cavity. Small-animal models are not suitable for large instrumentation, and difficult IV access thwarts antibiotic administration. In contrast, large-animal models can be implanted with clinically relevant instrumentation and are resilient to repeat procedures to study postoperative infection. A canine model of infection offers a unique opportunity to design and investigate antimicrobial treatments through recruitment a rich population of canine patients, presenting with a natural disease that is suitable for randomized trials.

[Clinical application of nose ring drain technique combined with Ilizarov circular external fixation for Gustilo ⅢA Pilon fractures]

OBJECTIVE

To investigate the effectiveness of the nose ring drain (NRD) technique combined with Ilizarov circular external fixation in treatment of Gustilo ⅢA Pilon fracture.

METHODS

Between March 2017 and December 2019, 17 patients with Gustilo ⅢA Pilon fractures were admitted and treated with NRD technique combined with Ilizarov circular external fixation. Among them, there were 11 males and 6 females; the age ranged from 24 to 63 years, with an average of 38.2 years. There were 3 cases of traffic accident injury, 13 cases of falling injury, and 1 case of penetrating injury. There were 13 cases of emergency admittance and 4 cases of wound infection after surgical treatment. Furthermore, there were 2 cases of fibula fractures and 3 cases of lateral malleolus fractures.

RESULTS

All patients were followed up 8-12 months, with an average of 9.9 months. All wounds healed by first intention, and 4 patients with preoperative infection had no recurrence during the follow-up. The external fixator was removed after fracture healing in 17 patients at 3-7 months after operation (mean, 4.5 months). At last follow-up, the pain score of the ankle joint Kofoe score was 40-50, with an average of 44; the functional score was 17-27, with an average of 25; the mobility score was 8-18, with an average of 14; and the effectiveness was rated as excellent in 8 cases, good in 7 cases, and poor in 1 case.

CONCLUSION

For Gustilo ⅢA Pilon fractures, the NRD technique combined with Ilizarov circular external fixation has advantages of good fracture fixation and drainage effects, which greatly reduces the complications of traditional treatment options and the number of operations.

Extended-spectrum β-lactamase-producing Escherichia coli rib osteomyelitis with debridement and vacuum-assisted closure

Rib osteomyelitis is a rare disease, comprising 1% or less of all osteomyelitis. Treatment of rib osteomyelitis includes prolonged antibiotic therapy and surgical intervention. Indications for surgical treatment of rib osteomyelitis remain unclear, however, because of few reported cases. We report the first known case of extended-spectrum β-lactamase-producing Escherichia coli rib osteomyelitis caused by urosepsis. The 69-year-old male patient remains free of recurrence and symptoms after rib resection and vacuum-assisted closure treatment with antibiotic therapy. Rib osteomyelitis should be considered as differential diagnosis when patients report chest pain after bacteraemic infection. We recommend surgical treatment for patients with drug-resistant bacterial rib osteomyelitis.

Using Alendronic Acid Coupled Fluorescently Labelled SM Liposomes as a Vehicle for Bone Targeting

Background:

We recently developed a liposomal nanoparticle system that can be used for drug delivery and simultaneously be monitored by optical or photoacoustic imaging devices. Here we tested the efficacy of alendronate as a homing molecule in SM-liposomes for bone targeting.

Methods:

Alendronate was immobilized covalently on the liposomal surface and the fluorescent dye indocyanine green was used as a payload in the liposomes. The indocyanine green delivery was analyzed by 3D optical tomography, optical fluorescence scanner, photoacoustic imaging, and by ex-vivo biodistribution studies.

Results:

The results show that the alendronate, coupled to the liposomal surface, increases sphingomyelin containing liposome targeting up to several-folds.

Conclusion:

The alendronate targeted liposomes open possibilities for an application in active bone targeting.

Antimicrobial peptides - Advances in development of therapeutic applications

The severe infection is becoming a significant health problem which threaten the lives of patients and the safety and economy of society. In the way of finding new strategy, antimicrobial peptides (AMPs) - an important part of host defense family, emerged with tremendous potential. Up to date, huge numbers of AMPs has been investigated from both natural and synthetic sources showing not only the ability to kill microbial pathogens but also propose other benefits such as wound healing, anti-tumor, immune modulation. In this review, we describe the involvements of AMPs in biological systems and discuss the opportunity in developing AMPs for clinical applications. In the detail, their properties in antibacterial activity is followed by their application in some infection diseases and cancer. The key discussions are the approaches to improve biological activities of AMPs either by modifying chemical structure or incorporating into delivery systems. The new applications and perspectives for the future of AMPs would open the new era of their development.

Injectable Chitosan-Based Thermosensitive Hydrogel/Nanoparticle-Loaded System for Local Delivery of Vancomycin in the Treatment of Osteomyelitis

Purpose

Osteomyelitis, particularly chronic osteomyelitis, remains a major challenge for orthopedic surgeons. The traditional treatment for osteomyelitis, which involves antibiotics and debridement, does not provide a complete solution for infection and bone repair. Antibiotics such as vancomycin (VCM) are commonly used to treat osteomyelitis in clinical settings. VCM use is limited by a lack of effective delivery methods that provide sustained, high doses to entirely fill irregular bone tissue to treat infections.

Methods

We engineered a chitosan (CS)-based thermosensitive hydrogel to produce a VCM-nanoparticle (NPs)/Gel local drug delivery system. The VCM-NPs were formed with quaternary ammonium chitosan and carboxylated chitosan nanoparticles (VCM-NPs) by positive and negative charge adsorption to enhance the encapsulation efficiency and drug loading of VCM, with the aim of simultaneously preventing infection and repairing broken bones. This hydrogel was evaluated in a rabbit osteomyelitis model.

Results

The VCM-NPs had high encapsulation efficiency and drug loading, with values of 60.1±2.1% and 24.1±0.84%, respectively. When embedded in CS-Gel, the VCM-NPs maintained their particle size and morphology, and the injectability and thermosensitivity of the hydrogel, which were evaluated by injectability test and rheological measurement, were retained. The VCM-NPs/Gel exhibited sustained release of VCM over 26 days. In vitro tests revealed that the VCM-NPs/Gel promoted osteoblast proliferation and activity against Staphylococcus aureus. In vivo, VCM-NPs/Gel (with 10 mg vancomycin per rabbit) was used to treat rabbits with osteomyelitis. The VCM-NPs/Gel showed excellent anti-infection properties and accelerating bone repair under osteomyelitis conditions.

Conclusion

The reported multifunctional NPs hydrogel system for local antibiotic delivery (VCM-NPs/Gel) showed bone regeneration promotion and anti-infection properties, demonstrating significant potential as a scaffold for effective treatment of osteomyelitis.

Modifications of Hydroxyapatite by Gallium and Silver Ions-Physicochemical Characterization, Cytotoxicity and Antibacterial Evaluation

Hydroxyapatite (HA) powders enriched with silver or gallium ions or both were synthesized by two different routes: standard precipitation and the solid-state method. The powders were characterized by using several methods: inductively coupled plasma optical emission spectrometry (ICP-OES), powder X-ray diffractometry (PXRD), transmission electron microscopy (TEM), infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance spectroscopy (ssNMR). The effects of enrichment of the HAs in Ag⁺ or Ga³⁺ or both on in vitro cytotoxicity and microbiological activity were discussed. PXRD experiments showed that the samples obtained by the wet method consisted of single-phase nanocrystalline HA, while the samples prepared via the solid-state method are microcrystalline with a small amount of calcium oxide. The introduction of higher amounts of silver ions was found to be more effective than enriching HA with small amounts of Ag⁺. Gallium and silver ions were found not to affect the lattice parameters. Ga³⁺ affected the crystallinity of the samples as well as the content of structural hydroxyl groups. Among samples synthesized by the wet method, only one (5Ag-HAw) was cytotoxic, whereas all Ga-containing samples obtained by the dry method showed cytotoxicity. In the preliminary antimicrobial test all the materials containing "foreign" ions showed high antibacterial activity.

Modified algorithm for managing postoperative osteomyelitis following fracture fixation with Cierny-Mader type

Background

No standardized protocol has been suggested in the treatment of postoperative osteomyelitis following fracture fixation. Our team evaluates the clinical efficacy of the modified algorithm for managing postoperative osteomyelitis following fracture fixation with Cierny–Mader type.

Methods

Ninety-five wounds were reviewed from March 2009 to February 2016 in our hospital. Sixty-one wounds were treated by the modified algorithm as follows: stable hardware + bone not healed Cierny–Mader 1 type = remove hardware, temporary stabilize; stable hardware + bone not healed Cierny–Mader 2 type = retain hardware ; stable hardware + bone not healed Cierny–Mader for type 3 and type 4 = remove hardware, temporary stabilize/Ilizarov technique; unstable hardware + bone not healed = remove hardware, temporary stabilize/Ilizarov technique; and stable hardware + bone healed = remove hardware. Thirty-four wounds were treated by the conventional algorithm. Autodermoplasty, flap transfer, myocutaneous flap, and other methods including antibiotic irrigation and drug delivery system were used in wound repair.

Results

The patients treated with modified algorithm had a significantly reduced recurrence (P < 0.01) and increased results of negative bacterial cultures (P < 0.01); however, a decrease in the number of retained hardware cases was observed (P < 0.05). For those treated with tissue reconstruction, there was no significance (P > 0.05) compared with the conventional group.

Conclusions

The modified algorithm for the postoperative osteomyelitis following fracture fixation according to the stability of the hardware and Cierny–Mader type represents a good clinical efficacy in the management of postoperative osteomyelitis. This procedure is simple and shows promising results; more clinical evidence is needed to confirm the existing findings and optimize the treatment of postoperative osteomyelitis following fracture fixation.

Modeling Early Stages of Bone and Joint Infections Dynamics in Humans: A Multi-Agent, Multi-System Based Model

Diagnosis and management of bone and joint infections (BJI) is a challenging task. The high intra and inter patient's variability in terms of clinical presentation makes it impossible to rely on a systematic description or classical statistical analysis for its diagnosis. Advances can be achieved through a better understanding of the system behavior that results from the interactions between the components at a micro-scale level, which is difficult to mastered using traditional methods. Multiple studies from the literature report factors and interactions that affect the dynamics of the BJI system. The objectives of this study were (i) to perform a systematic review to identify relevant interactions between agents (cells, pathogens) and parameters values that characterize agents and interactions, and (ii) to develop a two dimensional computational model of the BJI system based on the results of the systematic review. The model would simulate the behavior resulting from the interactions on the cellular and molecular levels to explore the BJI dynamics, using an agent-based modeling approach. The BJI system's response to different microbial inoculum levels was simulated. The model succeeded in mimicking the dynamics of bacteria, the innate immune cells, and the bone mass during the first stage of infection and for different inoculum levels in a consistent manner. The simulation displayed the destruction in bone tissue as a result of the alteration in bone remodeling process during the infection. The model was used to generate different patterns of system behaviors that could be analyzed in further steps. Simulations results suggested evidence for the existence of latent infections. Finally, we presented a way to analyze and synthesize massive simulated data in a concise and comprehensive manner based on the semi-supervised identification of ordinary differential equations (ODE) systems. It allows to use the known framework for temporal and structural ODE analyses and therefore summarize the whole simulated system dynamical behavior. This first model is intended to be validated by in vivo or in vitro data and expected to generate hypotheses to be challenged by real data. Step by step, it can be modified and complexified based on the test/validation iteration cycles.

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.

A systematic review of the single-stage treatment of chronic osteomyelitis

BACKGROUND

Despite advances in surgery, the treatment of chronic osteomyelitis remains complex and is often associated with a significant financial burden to healthcare systems. The aim of this systematic review was to identify the different single-stage procedures that have been used to treat adult chronic osteomyelitis and to evaluate their effectiveness.

METHODS

Ovid Medline and Embase databases were searched for articles on the treatment of chronic osteomyelitis over the last 20 years. A total of 3511 journal abstracts were screened by 3 independent reviewers. Following exclusion of paediatric subjects, animal models, non-bacterial osteomyelitis and patients undergoing multiple surgical procedures, we identified 13 studies reported in English with a minimum follow-up period of 12 months. Data extraction and quality assessment were performed for all studies. Non-recurrence was defined as resolution of pain without recurrence of sinuses or need for a second procedure to treat infection within the described follow-up period.

RESULTS

A total of 505 patients with chronic osteomyelitis underwent attempted single-stage procedures. Following debridement, a range of techniques have been described to eliminate residual dead space including biologic and non-biologic approaches. These include musculocutaneous flaps, insertion of S53P4 glass beads or packing with antibiotic-loaded ceramic or calcium-sulphate pellets. The average follow-up ranged from 12 to 110 months. The most common organism isolated was Staphylococcus aureus (35.2%). Non-recurrence ranged from 0 to 100%. Debridement alone was statistically significantly inferior to approaches that included dead space management (54.5% versus 90% non-recurrence). Biologic and non-biologic approaches to dead space management were comparable (89.8% versus 94.2% non-recurrence).

CONCLUSION

A wide range of single-stage procedures have been performed for the treatment of chronic osteomyelitis. In general, studies were small and observational with various reporting deficiencies. No one dead space management technique appears to be superior, but debridement alone that leaves residual dead space should be avoided.

Osteogenic and antibacterial dual functions of a novel levofloxacin loaded mesoporous silica microspheres/nano-hydroxyapatite/polyurethane composite scaffold

Lev/MSNs/n-HA/PU has been proved to be a novel scaffold material to treat bone defect caused by chronic osteomyelitis. We have previously identified that this material can effectively treat chronic osteomyelitis caused by Staphylococcus aureusin vivo. However, the potential mechanisms of antibacterial and osteogenic induction properties remain unclear. Thus, for osteogenesis property, immunohistochemistry, PCR, and Western blot were performed to detect the expression of osteogenic markers. Furthermore, flow cytometry and TUNEL were applied to analyze MC3T3-E1 proliferation and apoptosis. For antibacterial property, the material was co-cultivated with bacteria, bacterial colony forming units was counted and the release time of the effective levofloxacin was assayed by agar disc-diffusion test. Moreover, scanning electron microscope was applied to observe adhesion of bacteria. In terms of osteogenic induction, we found BMSCs adherently grew more prominently on Lev/MSNs/n-HA/PU. Lev/MSNs/n-HA/PU also enhanced the expression of osteogenic markers including OCN and COL1α1, as well as effectively promoted the transition from G1 phase to G2 phase. Furthermore, Lev/MSNs/n-HA/PU could reduce apoptosis of MC3T3-E1. Besides, both Lev/MSNs/n-HA/PU and n-HA/PU materials could inhibit bacterial colonies, while Lev/MSNs/n-HA/PU possessed a stronger antibacterial activities, and lower bacterial adhesion than n-HA/PU. These results illustrated that Lev/MSNs/n-HA/PU composite scaffold possess favorable compatibility in vitro, which induce osteogenic differentiation of MSCs, promote proliferation and differentiation of MC3T3-E1, and inhibit apoptosis. Moreover, clear in vitro antibacterial effect of Lev/MSNs/n-HA/PU was also observed. In summary, this study replenishes the potential of Lev/MSNs/n-HA/PU composite scaffold possess dual functions of anti-infection and enhanced osteogenesis for future clinical application.

Treatment of forearm diaphyseal defect by distraction compression bone transport and continued distraction for radial head reduction: A case study

Treatment of infected forearm nonunion and defects represents a difficult task for the operating surgeons. Conventional methods like composite and vascularized fibular grafts and the induced membranes filled with cancellous autografts or the Masquelet technique have been reported to be useful and successful, but sometimes it is difficult to predict the outcome and cannot address simultaneous deformities or the need to apply gradual distraction for reduction of a chronically dislocated radial head. Ilizarov technique has an answer for such conditions. We report a 43 years old man with infected ulnar defect and dislocated radial head as a result of infected Monteggia fracture: the patient was successfully treated by Ilizarov bone transport after failed attempts by bone spacer and fibular graft.

Cost-Effectiveness Study of One-Stage Treatment of Chronic Osteomyelitis with Bioactive Glass S53P4

This study was set up to evaluate the costs of a one-stage treatment of chronic osteomyelitis using bioactive glass S53P4 versus a two-stage treatment using gentamicin-loaded PMMA beads. Furthermore, a cost-effectiveness analysis was performed from a hospital’s perspective together with the evaluation of clinical outcome. A treatment group (n = 25) receiving one-stage surgery with bioactive glass was retrospectively compared with a two-stage control group (n = 25). An assessment was made of all costs included from first outpatient visit until one year after treatment. Bootstrap simulation and sensitivity analyses were performed. The primary endpoint was cost-effectiveness with clinical outcome as the secondary endpoint. The base case analyses shows dominance of the one-stage treatment with bioactive glass S53P4 due to lower costs and a better clinical outcome. Sensitivity analyses confirm these findings. This study is the first in its kind to show one-stage treatment of chronic osteomyelitis with bioactive glass S53P4 to be cost-effective.

The Effect of Age on Outcome in Excision of Chronic Osteomyelitis with Free Muscle Flap Reconstruction

Introduction: Curative surgical treatment of chronic osteomyelitis often requires free tissue transfer if there is significant soft tissue compromise. We investigated whether age influenced outcomes of curative osteomyelitis excision in those patients requiring free muscle flap soft tissue reconstruction.

Methods: We assessed ninety-five consecutive patients treated with excision of chronic osteomyelitis, skeletal stabilisation/reconstruction and free muscle transfer between 2006 and 2012. We compared outcomes of those aged ≥60 years (n=23) with those <60 years old (n=72).

Results: Groups were similar with regard to Cierny and Mader anatomic type and physiological host classification. Length of procedure and length of hospital stay were similar for both groups. There was a greater proportion of ASA grade III patients in the older cohort. Infection recurrence occurred in one of the older cohort (4.3%) and in seven patients in the younger cohort (9.9%) at a mean follow-up of 42 months (range 11-131 months), this was not statistically significant (p=0.27874). There were five free flap losses (6.9%) in the younger group and none in the older group. A greater proportion of patients from the younger cohort required further unplanned surgery (28%) compared to the older group (4.3%), which was statistically significant (p=0.01174). Seven patients (7.4%) had serious medical complications - five of whom were in the younger cohort, including one mortality.

Conclusions: Both the young and old can enjoy satisfactory outcomes from surgical resection of chronic osteomyelitis with simultaneous orthoplastic reconstruction including free tissue transfer. Age alone should not be a barrier to potentially curative surgical treatment.

Evolving concepts in bone infection: redefining "biofilm", "acute vs. chronic osteomyelitis", "the immune proteome" and "local antibiotic therapy"

Osteomyelitis is a devastating disease caused by microbial infection of bone. While the frequency of infection following elective orthopedic surgery is low, rates of reinfection are disturbingly high. Staphylococcus aureus is responsible for the majority of chronic osteomyelitis cases and is often considered to be incurable due to bacterial persistence deep within bone. Unfortunately, there is no consensus on clinical classifications of osteomyelitis and the ensuing treatment algorithm. Given the high patient morbidity, mortality, and economic burden caused by osteomyelitis, it is important to elucidate mechanisms of bone infection to inform novel strategies for prevention and curative treatment. Recent discoveries in this field have identified three distinct reservoirs of bacterial biofilm including: Staphylococcal abscess communities in the local soft tissue and bone marrow, glycocalyx formation on implant hardware and necrotic tissue, and colonization of the osteocyte-lacuno canalicular network (OLCN) of cortical bone. In contrast, S. aureus intracellular persistence in bone cells has not been substantiated in vivo, which challenges this mode of chronic osteomyelitis. There have also been major advances in our understanding of the immune proteome against S. aureus, from clinical studies of serum antibodies and media enriched for newly synthesized antibodies (MENSA), which may provide new opportunities for osteomyelitis diagnosis, prognosis, and vaccine development. Finally, novel therapies such as antimicrobial implant coatings and antibiotic impregnated 3D-printed scaffolds represent promising strategies for preventing and managing this devastating disease. Here, we review these recent advances and highlight translational opportunities towards a cure.

Chronic Osteomyelitis Revisited: A Case Report

Chronic osteomyelitis treatment is always a challenge to orthopaedic surgeons which requires great dedication and perseverance. We report a successful limb salvage case of a 46-year-old man who suffered from a left tibia chronic osteomyelitis with soft tissue defect. The treatment approach was a thorough wound debridement of devitalized tissues and necrotized bone, commencement of culture-directed antibiotics, reconstruction with vascularized osteomyocutaneous fibula flap, and skeletal stabilization with internal fixation. As compared to below knee amputation, the result we obtained in this case is more promising with regard to mobility and function.

Cytokine Regulation from Human Peripheral Blood Leukocytes Cultured In Vitro with Silver Doped Bioactive Glasses Microparticles

Bioactive glasses (BG) applications include tissue engineering for bone regeneration, coating for implants, and scaffolds for wound healing. BG can be conjugated to ions like silver, which might add some antimicrobial properties to this biomaterial. The immunomodulatory activity of ion-doped bioactive glasses particles was not investigated before. The aim of this work was to evaluate the cytotoxic and immunomodulatory effect of BG and silver-doped bioactive glass (BGAg) in human peripheral blood cells. BG and BGAg samples belonging to the system 58SiO₂•(36-x)CaO·6P₂O₅·xAg₂O, where x = 0 and 1 mol%, respectively, were synthesized via sol–gel method and characterized. Cytotoxicity, modulation of cytokine production (TNF-α, IL-1β, IL-6, IL-4, and IL-10), and oxidative stress response were investigated in human polymorphonuclear cells (PMNs) and peripheral blood mononuclear cells (PBMCs) cultures. Cell viability in the presence of BG or BGAg was concentration-dependent. In addition, BGAg presented higher PBMCs toxicity (LC50 = 0.005%) when compared to BG (LC50 = 0.106%). Interestingly, interleukin4 was produced by PBMCs in response to BG and BGAg in absence of phytohemagglutinin (PHA) and did not modulate PHA-induced cytokine levels. Subtoxic concentrations (0.031% for BG and 0.0008% for BGAg) did not change other cytokines in PBMCs nor reactive oxygen species (ROS) production by PMN. However, BG and BGAg particles decreased zymosan-induced ROS levels in PMN. Although ion incorporation increased BG cytotoxicity, the bioactive glass particles demonstrated a in vitro anti-inflammatory potencial. Future studies are needed to clarify the scavenger potential of the BG/BGAg particles/scaffolds as well as elucidate the effect of the anti-inflammatory potential in modulating tissue growth in vivo.