Duration of post-surgical antibiotics in chronic osteomyelitis: empiric or evidence-based?

Continuous local antibiotic perfusion for deep infection of the foot and ankle

BACKGROUND

This study aimed to report the outcome of deep infections of the foot and ankle, which are among the most challenging orthopedic conditions to treat, after continuous local antibiotic perfusion.

METHODS

Eleven patients with deep foot and ankle infections were treated with continuous local antibiotic perfusion between January 2019 and March 2024. After surgical debridement, we performed continuous perfusion of high concentrations of gentamicin (60 mg/50 ml) directly into the infected bone and soft tissue for two weeks using bone marrow needles and double-lumen tubes. Patient characteristics, infection relapse, and adverse events were investigated.

RESULTS

The mean age of the patients was 53 years (range 12-79 years), with six males and five females. The infections were controlled without additional surgeries in ten patients with a mean follow-up of 40 months (12-62 months). Two patients developed a fungal infection, of which one required an additional debridement surgery, and the other was treated with oral antifungal medication. No adverse events occurred due to high-concentration gentamicin.

CONCLUSIONS

Short-term infection control was achieved using continuous local antibiotic perfusion; thus, it can be a treatment option for deep infections of the foot and ankle.

Piperacillin/tazobactam-induced sudden severe thrombocytopenia in a patient with a pressure ulcer: a case report

The standard treatment for an infected pressure ulcer (PU) with osteomyelitis is debridement, wound coverage and antibiotic administration. However, systemic administration of antibiotics in patients with osteomyelitis is controversial, and the optimal treatment duration for chronic osteomyelitis has not been standardised. We report a case of sudden severe thrombocytopenia induced by piperacillin/tazobactam (PIPC/TAZ) in a patient with PU-related osteomyelitis. A 57-year-old male patient with paraplegia, using a wheelchair full-time, presented to our plastic surgery department with infection of a stage IV hard-to-heal ischial PU. We surgically debrided the necrotising tissue and raised an ipsilateral biceps femoris musculocutaneous propeller flap for wound coverage. Polymicrobial infections, including Pseudomonas aeruginosa, were detected in the bone biopsy sample; therefore, systemic PIPC/TAZ was administered for the osteomyelitis. Unexpectedly, during the next 12 days of antibiotic administration, the patient's platelet count acutely dropped to 1×103/μl over three days. Based on a series of examinations, PIPC/TAZ was suspected to be the most likely cause of the severe thrombocytopenia. After drug discontinuation, the thrombocytopenia gradually improved. PIPC/TAZ is one of the most widely used antibiotic combinations in the plastic surgery field; it is conventionally administered for hard-to-heal wounds such as PUs and diabetic foot. The present case suggests that surgeons must take special precautions for patients undergoing PIPC/TAZ treatment. In this report, PIPC/TAZ-induced thrombocytopenia and the efficacy of antibiotic treatment for PU-related osteomyelitis are discussed in light of the available literature.

Interfacial and Defect Polarization Enhanced Microwave Noninvasive Therapy for Staphylococcus aureus-Infected Chronic Osteomyelitis

Chronic osteomyelitis (COM), is a long-term, constant, and intractable disease mostly induced by infection from the invasion of Staphylococcus aureus (S. aureus) into bone cells. Here, we describe a highly effective microwave (MW) therapeutic strategy for S. aureus-induced COM based on the in situ growth of interfacial oxygen vacancy-rich molybdenum disulfide (MoS2)/titanium carbide (Ti3C2Tx) MXene with oxygen-deficient titanium dioxide (TiO2-x) on Ti3C2Tx (labeled as HU-MoS2/Ti3C2Tx) by producing reactive oxygen species (ROS) and heat. HU-MoS2/Ti3C2Tx produced heat and ROS, which could effectively treat S. aureus-induced COM under MW irradiation. The underlying mechanism determined by density functional theory (DFT) and MW vector network analysis was that HU-MoS2/Ti3C2Tx formed a high-energy local electric field under MW irradiation, consequently generating more high-energy free electrons to pass and move across the interface at a high speed and accelerate by the heterointerface, which enhanced the charge accumulation on both sides of the interface. Moreover, these charges were captured by the oxygen species adsorbed at the HU-MoS2/Ti3C2Tx interface to produce ROS. MoS2 facilitated multiple reflections and scattering of electromagnetic waves as well as enhanced impedance matching. Ti3C2Tx enhanced the conduction loss of electromagnetic waves, while functional groups induced dipole polarization to enhance attenuation of MW.

Systemic Antimicrobial Treatment of Chronic Osteomyelitis in Adults: A Narrative Review

Chronic osteomyelitis in adults is a complex condition that requires prolonged and intensive antimicrobial therapy, but evidence on optimal selection and duration of antibiotics is limited. A review of PubMed and Ovid Embase databases was conducted to identify systematic reviews, meta-analyses, retrospective and randomised controlled trials (RCTs) on antibiotic treatment outcomes in adults with chronic osteomyelitis. Three main areas of interest were investigated: short-term versus long-term antibiotic therapy, oral versus parenteral antibiotic therapy, and combination antibiotic therapy with rifampicin versus without rifampicin. A total of 36 articles were identified and findings were synthesised using a narrative review approach. The available literature suffers from limitations, including a lack of high-quality studies, inconsistent definitions, and varying inclusion/exclusion criteria among studies. Most studies are open-labelled and lack blinding. Limited high-quality evidence exists that oral therapy is non-inferior to parenteral therapy and that shorter antibiotic duration might be appropriate in low-risk patients. Studies on the impact of rifampicin are inconclusive. Further well-designed studies are needed to provide more robust evidence in these areas.

Sustained Release of Antifungal and Antibacterial Agents from Novel Hybrid Degradable Nanofibers for the Treatment of Polymicrobial Osteomyelitis

This study aimed to develop a drug delivery system with hybrid biodegradable antifungal and antibacterial agents incorporated into poly lactic-co-glycolic acid (PLGA) nanofibers, facilitating an extended release of fluconazole, vancomycin, and ceftazidime to treat polymicrobial osteomyelitis. The nanofibers were assessed using scanning electron microscopy, tensile testing, water contact angle analysis, differential scanning calorimetry, and Fourier-transform infrared spectroscopy. The in vitro release of the antimicrobial agents was assessed using an elution method and a high-performance liquid chromatography assay. The in vivo elution pattern of nanofibrous mats was assessed using a rat femoral model. The experimental results demonstrated that the antimicrobial agent-loaded nanofibers released high levels of fluconazole, vancomycin, and ceftazidime for 30 and 56 days in vitro and in vivo, respectively. Histological assays revealed no notable tissue inflammation. Therefore, hybrid biodegradable PLGA nanofibers with a sustainable release of antifungal and antibacterial agents may be employed for the treatment of polymicrobial osteomyelitis.

Research Status and Hotspots of Chronic Osteomyelitis: A Bibliometric and Visualized Analysis

OBJECTIVE

The treatment of chronic osteomyelitis (COM) is extremely challenging for physicians and patients. It is of great significance to explore the research status, development trend and future research hotspots in the field of COM to promote the development of this field. This study is aimed to explore the global research status of COM and predict its future research hotspots based on bibliometric and visualized analysis.

METHODS

Web of Science core collection database was used to search the related literature of COM from 1994 to 2020. All data were imported into Microsoft Excel 2019 for collation. Additionally, the literature quality of countries, authors, journals, and institutions is evaluated. The VOS viewer software was used for conducting co-analysis, co-citation analysis, and keyword co-occurrence analysis of literature to analyze the global status and predict the future hotspots of the COM field.

RESULTS

A total of 726 articles were retrieved in this study. The number of global publications shows a trend of wave growth, but the increase is not significant. It is expected that the number of COM articles will remain at more than 50 per year in the next decade. The COM literature published in the United States (Publications = 160, H index = 37, average citations per item = 28.63) is of the highest quality. Girschick HJ (Publications = 16, H index = 14, average citations per item = 52.25) is the most contributed scholar in the field of COM. UNIV IOWA (Publications = 15, H index = 11, average citations per item = 57.27) and UNIV WURZBURG (Publications = 18, H index = 15, average citations per item = 47.5) are influential institutions in the field of COM. The results of co-occurrence analysis show that the field of COM can be roughly divided into the following five modules: COM surgical research, COM basic research, COM diagnosis-related research, chronic recurrent multifocal osteomyelitis (CRMO)-related research, risk factors of COM. Risk factors of COM are the module with the highest concentration of hot words.

CONCLUSION

COM-related research will continue to develop further in the next decade. The diagnosis research and risk factors of COM are the most popular research modules in recent years. Some controversial or troubled issues including the efficacy of perforator flap and fascia flap covering soft tissue, searching exclusive detection methods for the diagnosis of COM and bisphosphonates and biological agents in the treatment of CRMO may lead to the development of the COM field.

Implantable drug delivery systems for the treatment of osteomyelitis

Osteomyelitis is an infection of the bone tissue and bone marrow which is becoming increasingly difficult to treat due to the infection causing pathogens associated. Staphylococcus aureus is one of the main bacteria that causes this infection, which has a broad spectrum of antibiotic resistance making it extremely difficult to treat. Conventional metal implants used in orthopaedic applications often have the drawback of implant induced osteomyelitis as well as the requirement of a second surgery to remove the implant once it is no longer required. Recently, attention has been focused on the design and fabrication of biodegradable implants for the treatment of bone infection. The main benefit of biodegradable implants over polymethylmethacrylate (PMMA) based non-degradable systems is that they do not require a second surgery for removal and so making degradable implants safer and easier to use. The main purpose of a biodegradable implant is to provide the necessary support and conductivity to allow the bone to regenerate whilst themselves degrading at a rate that is compatible with the rate of formation of new bone. They must be highly biocompatible to ensure there is no inflammation or irritation within the surrounding tissue. During this review, the latest research into antibiotic loaded biodegradable implants will be explored. Their benefits and drawbacks will be compared with those non-degradable PMMA beads, which is the stable material used within antibiotic loaded implants. Biodegradable implants most frequently used are based on biodegradable natural and synthetic polymers. Implants can take the form of many different structures; the most commonly fabricated structure is a scaffold. Other structures that will be explored within this review are hydrogels, nanoparticles and surface coatings, all with their own benefits/drawbacks.

Pharmaceutical-eluting hybrid degradable hydrogel/microparticle loaded sacs for finger joint interpositional arthroplasty

Despite recent advances in medical technology, treatment of chronic osteomyelitis in the small joint of the hand remains challenging. Here, we exploited hybrid biodegradable hydrogel/microparticle/polycaprolactone (PCL) sacs for finger joint interpositional arthroplasty via electrospraying and rotational molding techniques. Degradable Pluronic F127, poly(lactic-co-glycolic acid) (PLGA), and PCL were starting materials for the hydrogels, microparticles, and sac, respectively. Vancomycin, ceftazidime, and lidocaine were the embedded pharmaceuticals. The in vitro and in vivo drug release behaviors of hybrid drug-eluting sacs were assessed. The empirical outcomes show that the size distribution of the electrosprayed vancomycin/ceftazidime/lidocaine PLGA microparticles was 8.25 ± 3.35 μm. Biodegradable PCL sacs offered sustainable and effective release of vancomycin, ceftazidime, and lidocaine, respectively, after 30, 16, and 11 days in vitro. The sacs also discharged high levels of anti-microbial agents for 56 days and analgesics for 14 days in a rabbit knee joint model. The blood urea nitrogen (creatinine) levels remained normal at various time points: 16.5 ± 2.5 mg/dL (0.85 ± 0.24 mg/dL), 20.0 ± 1.4 mg/dL (1.0 ± 0.16 mg/dL), 19.3 ± 2.4 mg/dL (1.13 ± 0.15 mg/dL), and 20.0 ± 2.16 mg/dL (1.0 ± 0.16 mg/dL) at days 7, 14, 21, and 35, respectively. The empirical outcomes of this study suggested that the hybrid biodegradable drug-eluting sacs with extended liberation of pharmaceuticals may find applications in the small joints for post-operative pain relief and infection control.

Chronic Osteomyelitis of the Jaw: Pivotal Role of Microbiological Investigation and Multidisciplinary Management—A Case Report

A 15-year-old girl with a history of recurrent painful orofacial swelling was diagnosed on the basis of clinical findings, histopathological examination and imaging modalities as having primary chronic osteomyelitis of the jaw. Initial microbiological samples were performed but were inconclusive. She received multiple empirical antibiotic therapies and NSAIDs for 3 years without complete remission. Only MALDI-TOF (Matrix-Assisted Laser Desorption/Ionization–Time Of Flight) analysis after additional multiple microbiological bone samples with adequate techniques yielded the final diagnosis of bacterial chronic osteomyelitis of the jaw. Its management requires a multidisciplinary approach, involving oral and maxillofacial surgeons, infectiologists and microbiologists, to limit treatment failure. Antibiotic therapy without surgery for 6 months achieved the complete radiographic resolution of the CBCT (Cone Beam Computed Tomography) and the normalization of laboratory tests. After 2 years of follow-up, no relapse had been reported. Modern microbiological investigation and sampling techniques are critical for the accurate diagnosis and management of osteomyelitis of the jaw, especially in unusual and clinically misleading forms of this infection.

A nomogram for decision-making assistance on surgical treatment of chronic osteomyelitis in long bones: Establishment and validation based on a retrospective multicenter cohort

BACKGROUND

Chronic osteomyelitis remains a major challenge for orthopedic surgeons due to its high recurrence rate. Surgeons currently have few tools to estimate the likelihood of individual recurrence. We here aimed to develop a nomogram to better estimate individual recurrence rate after surgical treatment of chronic osteomyelitis in long bones.

METHODS

We first retrospectively identified patients as training cohort who had received surgical treatment of chronic osteomyelitis in long bones between January 2010 and January 2016 from four hospitals. Patient demographic, microbiological, clinical, and therapeutic variables were collected and analyzed. Univariate and multivariate analyses were performed successively to identify independently predictive factors for recurrence. To reduce overfitting, the Bayesian information criterion was used to reduce variables in the original model. Nomograms were created with the reduced model after model selection. The nomogram was then internally validated with bootstrap resampling. We then further validated the performance of the established nomogram in validation cohort (data from two distinct institutions).

RESULTS

Recurrence was found in 136 of 655 (20.8%) and 52 of 201 patients (25.9%) in training and validation cohorts respectively. We included six independent prognostic factors for recurrence in our prediction model: number of previous recurrences, epiphysial involvement, preoperative serum albumin level, axial length of the infectious lesion, lesion-removal method, and application of a muscular flap. After incorporating these six factors, the nomogram achieved good discrimination, with concordance indexes of 0.82 (95% CI, 0.79-0.85) and 0.80 (95% CI, 0.78-0.83) in predicting recurrence in the training and validation cohorts, respectively. Calibration curves were well fitted for both training and validation cohorts.

CONCLUSIONS

Our nomogram achieved good preoperative prediction of recurrence in chronic osteomyelitis of long bones. Using this nomogram, the recurrence risk can be confidently predicted for each patient and treatment plan. After considering and discussing the functional prognosis with patients, physicians can establish a rational therapeutic plan.

LEVEL OF EVIDENCE

Prognostic, Level III.

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.

Early oral switch to combined cefixime therapy for management of osteoarticular infections in pediatric sickle cell disease patients: A descriptive analysis

BACKGROUND

The treatment of osteoarticular infections in pediatric patients with sickle cell disease (SCD) is a challenging task for the practitioner. The aim of this study is to evaluate cefixime for the treatment of osteoarticular infections in pediatric SCD patients by retrospective design.

METHODS

This study was done in the pediatric hospital of King Saud Medical City, Riyadh, Saudi Arabia. The data was obtained from medical records of patients aged 1-16 years admitted between January 2019 to December 2020, diagnosed with SCD and received cefixime for the treatment of OI. A descriptive study for pediatric patients admitted between January 2019 to December 2020 diagnosed with sickle cell disease and diagnosed with osteoarticular infection. All patients were treated with cefixime. Medians and interquartile ranges (IQRs) were used for the descriptive analysis.

RESULTS

A total of 260 patients were screened, and 51 cases [osteomyelitis (OM), n = 43, and septic arthritis (SA), n = 8] met the inclusion criteria. The median age of OM patients was 7 years, with males making up 67.4% of the cohort. The median length of IV antibiotics and hospital stays were 10 days and 11 days, respectively. The median total duration of antibiotic use was 37 and 25 days for OM and SA, respectively. The treatment success rate was 88% in OM cases and 100% in SA patients. Readmission was noted in 39.5% of the OM patients, while only 25% of the SA patients were recorded for reinfection.

CONCLUSION

The study's findings revealed that Cefixime is a viable oral alternative for treating osteoarticular infection in pediatric SCD patients. Nonetheless, a prospective investigation is required to corroborate the findings of this study.

Combination of kaempferol and azithromycin attenuates Staphylococcus aureus-induced osteomyelitis via anti-biofilm effects and by inhibiting the phosphorylation of ERK1/2 and SAPK

Osteomyelitis is bacterial infection of bone, commonly caused by Staphylococcus aureus. This work aims to study the potential of azithromycin and kaempferol against chronic osteomyelitis induced by azithromycin-resistant Staphylococcus aureus (ARSA). It was noticed that rats tolerated the treatments with no diarrhoea or weight loss; also, no deaths were observed in rats. The treatment by azithromycin alone failed to inhibit bacterial growth and also had no effect on the infection condition of bone, although the treatment decreased the levels of interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α), but did not improve the oxidative stress levels. Kaempferol monotherapy slightly inhibited bacterial growth and bone infection; the treatment also inhibited the levels of IL-6 and (TNF-α). The treatment also improved the antioxidant status. However, the combined treatment of azithromycin and kaempferol significantly suppressed bacterial growth and bone infection and modulated oxidative stress. In vitro, the combined treatment inhibited the levels of IL-6 and TNF-α, and also suppressed the phosphorylation of ERK1/2 and stress-activated protein kinase (SAPK). The combined treatment also showed anti-biofilm activity in ARSA. The combination attenuates ARSA-induced osteomyelitis in rats compared with their treatments alone by reducing oxidative stress, inhibiting the phosphorylation of ERK1/2 and SAPK and inhibiting biofilm formation.

Retrospective study of the efficacy of vascularized tissue transfer for treating antibiotic-resistant bacteria-infected wound: Comparison with clean and antibiotic-sensitive bacteria-infected wound

If wounds are infected with bacteria resistant to an empirical antibiotic regimen, effective wound treatment will be delayed. This can delay wound healing and lengthen hospital stays, increasing the costs to patients. Long-term antibiotic use can also result in minor and major complications, such as diarrhea, antibiotic resistance, or life-threatening leukopenia. Multidrug-resistant (MDR) bacteria make wound treatment even more difficult. Traditionally, surgeons thought that adequate infection control should be established before soft tissue coverage. However, wounds infected by MDR do not heal well with this traditional method and there are no optimal treatment guidelines for MDR bacteria-contaminated wounds.We reviewed 203 patients who underwent vascularized flap surgery from 2012 to 2019 to cover wounds. Class IV and I wounds were compared according to the Centers for Disease Control and Prevention classification. Class IV was further classified as antibiotic-resistant (ARB) and antibiotic-sensitive (ASB) bacteria. Wound size, mode, location, pathogens, healing time, and basic demographics were evaluated. Data were compared using Cramer's V and one-way ANOVA or independent t tests.The average healing time was longer in the ARB (19.7 [range 7-44] days) and ASB (17.9 [range 2-36] days) groups than in the Clean group (16.5 [range 7-28] days). Healing time differed in the 3 groups (P = .036). It was longer in the class IV group than in the class I group (P = .01). However, it was not statistically different between the ARB and ASB groups (P = .164).In our study the difference in healing time was small when vascularized tissue transfer was done in ARB-infected wound compared with ASB-infected and clean wound. It is necessary to perform surgery using vascularized tissue for the infected wound of antibiotic-resistant bacteria.

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.

Reconstruction of massive tibial bone and soft tissue defects by trifocal bone transport combined with soft tissue distraction: experience from 31 cases

BACKGROUND

Large post-traumatic tibial bone defects combined with soft tissue defects are a common orthopedic clinical problem associated with poor outcomes when treated using traditional surgical methods. The study was designed to investigate the safety and efficacy of trifocal bone transport (TFT) and soft-tissue transport with the Ilizarov technique for large posttraumatic tibial bone and soft tissue defects.

METHODS

We retrospectively reviewed 31 patients with massive posttraumatic tibial bone and soft tissue defects from May 2009 to May 2016. All of the eligible patients were managed by TFT and soft-tissue transport. The median age was 33.4 years (range, 2-58 years). The mean defect of bone was 11.87 cm ± 2.78 cm (range, 8.2-18.2 cm) after radical resection performed by TFT. The soft tissue defects ranged from 7 cm × 8 cm to 24 cm × 12 cm. The observed results included bone union time, wound close time and true complications. The Association for the Study and Application of the Method of Ilizarov (ASAMI) scoring system was used to assess bone and functional results and postoperative complications were evaluated by Paley classification.

RESULTS

The mean duration of follow-up after frame removal was 32 months (range, 12-96 months). All cases achieved complete union in both the elongation sites and the docking sites, and eradication of infection. The mean bone transport time was 94.04 ± 23.33 days (range, 63.7-147 days). The mean external fixation time was 22.74 ± 6.82 months (range, 14-37 months), and the mean external fixation index (EFI) was 1.91 ± 0.3 months/cm (range, 1.2-2.5 months/cm). The bone results were excellent in 6 patients, good in 14 patients, fair in 8 patients and poor in 3 patients. The functional results were excellent in 8 patients, good in 15 patients, fair in 5 patients and poor in 3 patients.

CONCLUSION

TFT, in conjunction with soft tissue transport technique, can give good results in most patients (in this article, good and excellent results were observed in 64% of patients). Soft tissue transport is a feasible method in providing good soft tissue coverage on the bone ends. Although it has no advantages over microvascular techniques, it might be an good alternative in the absence of an experienced flap surgeon. Nonetheless, high-quality controlled studies are needed to assess its long-term safety and efficacy.

An Antibiotic-Releasing Bone Void Filling (ABVF) Putty for the Treatment of Osteomyelitis

The number of total joint replacements (TJR) is on the rise with a corresponding increase in the number of infected TJR, which necessitates revision surgeries. Current treatments with either non-biodegradable, antibiotic-releasing polymethylmethacrylate (PMMA) based bone cement, or systemic antibiotic after surgical debridement do not provide effective treatment due to fluctuating antibiotic levels at the site of infection. Here, we report a biodegradable, easy-to-use "press-fitting" antibiotic-releasing bone void filling (ABVF) putty that not only provides efficient antibiotic release kinetics at the site of infection but also allows efficient osseointegration. The ABVF formulation was prepared using poly (D,L-lactide-co-glycolide) (PLGA), polyethylene glycol (PEG), and polycaprolactone (PCL) as the polymer matrix, antibiotic vancomycin, and osseointegrating synthetic bone PRO OSTEON for bone-growth support. ABVF was homogenous, had a porous structure, was moldable, and showed putty-like mechanical properties. The ABVF putty released vancomycin for 6 weeks at therapeutic level. Furthermore, the released vancomycin showed in vitro antibacterial activity against Staphylococcus aureus for 6 weeks. Vancomycin was not toxic to osteoblasts. Finally, ABVF was biodegradable in vivo and showed an effective infection control with the treatment group showing significantly higher bone growth (p < 0.001) compared to the control group. The potential of infection treatment and osseointegration makes the ABVF putty a promising treatment option for osteomyelitis after TJR.

Four versus six weeks of antibiotic therapy for osteoarticular infections after implant removal: a randomized trial

BACKGROUND

The optimal duration of antibiotic therapy for treating orthopaedic implant infections after surgical drainage and complete implant removal is unknown.

METHODS

This was a single-centre, unblinded, prospective trial randomizing (1:1) eligible patients to either 4 or 6 weeks of systemic, pathogen-targeted antibiotic therapy. Clinical trial registration number: ClinicalTrials.gov (NCT0362209).

RESULTS

We analysed 123 eligible patients (62 in the 4 week antibiotic arm and 61 in the 6 week arm) in the ITT analysis. The patients' median age was 64 years, 75 (61%) were men and 38 (31%) were immunocompromised. The most common types of infection treated included: two-stage exchange procedure for prosthetic joint infection (n = 38); orthopaedic plate infection (44) and infected nail implants (11). The median duration of post-explant intravenous antibiotic therapy was 4 days. Overall, 120 episodes (98%) were cured microbiologically and 116 (94%) clinically after a median follow-up period of 2.2 years. During follow-up, four patients had a clinical recurrence with a pathogen other than the initial causative agent. We noted recurrence of clinical infection in four patients in the 4 week arm and three patients in the 6 week arm (4/62 versus 3/61; χ2 test; P = 0.74); in all cases, this occurred at around 2 months following the end of antibiotic treatment.

CONCLUSIONS

We found no statistically significant difference in the rates of clinical or microbiological remission between patients randomized to only 4 compared with 6 weeks of systemic antibiotic therapy after removal of an infected osteoarticular implant.

Real-World Use of Oritavancin for the Treatment of Osteomyelitis

Osteomyelitis is a difficult-to-treat disease that can require both surgical debridement and a prolonged course of antimicrobial therapy. Current standard of care for the antimicrobial treatment of osteomyelitis is fraught with multiple challenges and limitations. Patients typically require the insertion of an indwelling catheter for single or multiple daily intravenous antibiotic infusions for up to 6 weeks. Currently, there are treatment guidelines for only vertebral osteomyelitis, indicating the complexity of the condition. Oritavancin is a long-acting, second-generation lipoglycopeptide, administered intravenously once per week, which has potential to be a useful alternative in the treatment of osteomyelitis. This article reviews occurrence and outcomes of off-label oritavancin use for treatment of osteomyelitis as described in case reports. Analysis included 23 patients treated for osteomyelitis with single- or multiple-dose oritavancin. Overall, clinical cure or improvement was achieved in 87% of patients, and adverse events were mild and reported in only two patients. Clinical efficacy was demonstrated in 81.8% of methicillin-resistant Staphylococcus aureus (MRSA), 71.4% of methicillin-sensitive S. aureus (MSSA), 50% of vancomycin-resistant Enterococcus (VRE), and in the single case of Streptococcus pyogenes. Oritavancin has shown efficacy against Gram-positive pathogens in osteomyelitis, and offers a possible outpatient treatment option for osteomyelitis patients. Future studies are needed to determine dosing frequency in osteomyelitis patients.

Need for appropriate specimen for microbiology diagnosis of chronic osteomyelitis

INTRODUCTION

Chronic osteomyelitis (COM) is a common infection, especially in developing countries. An adequate bone biopsy specimen processed with appropriate microbiology culture methods for isolation and identification of the causative organisms is considered as the gold standard for the diagnosis of osteomyelitis.

MATERIALS AND METHODS

The present study is a retrospective microbiology analysis of the specimen from 219 clinically diagnosed cases of COM between January 2013 and April 2016.

RESULTS

The overall culture positivity was 111/219 (50. 6%), colonization was seen in 22/219 (10.5%), while the rest 86/219 (39.3%) were culture-negative specimen; culture positivity was highest from tissue specimen (71/113, 62.8%). Among the swabs, 40/106 (37.7%) were culture positive. About 28/40 (70%) culture-positive swabs showed significant growth of Gram-positive organisms. Colonization with skin flora such as diphtheroids and Coagulase-negative Staphylococci was seen in 22/106 (20.7%) of the swabs. Sterile cultures (44/106, 41.6%) were high among the swab specimen. Gram-positives were most common (75/111, 67.56%). Staphylococcus aureus was the predominant organism isolated in 70/111 (63%) cases. Gram-negative bacilli showed a high level of antibiotic resistance.

CONCLUSION

As per our data, the culture yield from wound swabs was low or contaminated with normal skin flora, as compared to the biopsy or tissue specimen. Hence, an appropriate sampling of the infected bone using recommended protocols is highly essential for improving microbiological yield and the outcome of COM.

Treatment of a femoral septic nonunion in a dog with interlocking nail stabilization associated to corticospongious bone autograft and greater omentum flap: case report

ABSTRACT Chronic septic bone nonunion requires a well-designed therapeutic planning, demanding a multimodal treatment to achieve bone consolidation and elimination of infection. A successful case of an association of the major omentum flap with surgical stabilization with an interlocking nail for treatment of a femoral septic nonunion in dog is reported. The patient had partial functional return of the limb 30 days after surgery, negative bacterial culture with radiographic signs of bone healing and total functional return of the limb at 90th days after the surgical procedure.

Investigating clinical characteristics and prognostic factors in patients with chronic osteomyelitis of humerus

Background

Chronic osteomyelitis in the humerus, which has complex neuroanatomy and a good soft tissue envelope, represents a unique clinical challenge. However, there are relatively few related studies in the literature. This article retrospectively reviewed a large case series with the aims of sharing our management experiences and further determining factors associated with the outcomes.

Methods

Twenty-eight consecutive adult patients with a mean age of 36 years were identified by reviewing the osteomyelitis database of our clinic centre. The database was used to prospectively identify all osteomyelitis cases between 2013 and 2017, and all data then was retrospectively analysed.

Results

The mean follow-up period was 35 months (range 24–60). The aetiology was trauma in 43% (12) of the patients and haematogenous in 57% (16) of the patients, and Staphylococcus aureus was a solitary agent in 50% (14) of the patients. Host-type (Cierny’s classification) was IA in 8, IIIB in 11 and IVB in 9 patients. All patients required debridement followed by the placement of a temporary antibiotic-impregnated cement spacer (rod). Seventeen patients received a cement-coated plate for internal fixation after debridement, and 13 patients needed bone grafts when the spacer was staged removed. All patients attained an infection-free bone healing state at the final follow-up. The final average DASH (disabilities of the arm, shoulder and hand) score was 18.14 ± 5.39, while 6 patients (two developed traumatic olecranarthritis, four developed radial nerve injuries) showed the lowest levels of limb function (p = 0.000) and were unemployed. Three patients (type I; significant difference between type I versus type III and type IV patients, p < 0.05) experienced recurrence after debridement and underwent a second revision, which was not related to the bone graft (p = 0.226) or plate fixation (p = 0.050).

Conclusions

Humeral chronic osteomyelitis can be treated with general surgery and anti-infective therapy; medullary (type I) infection presents a challenge, and the antibiotic-coated cement plate provides favourable fixation without increasing recurrence of infections. Clinicians should be aware of potential iatrogenic nerve injuries when treating these patients with complicated cases, and an experienced surgeon may improve the outcome.

Strontium-releasing mesoporous bioactive glasses with anti-adhesive zwitterionic surface as advanced biomaterials for bone tissue regeneration

HYPOTHESIS

The treatment of bone fractures still represents a challenging clinical issue when complications due to impaired bone remodelling (i.e. osteoporosis) or infections occur. These clinical needs still require a radical improvement of the existing therapeutic approach through the design of advanced biomaterials combining the ability to promote bone regeneration with anti-adhesive properties able to minimise unspecific biomolecules adsorption and bacterial adhesion. Strontium-containing mesoporous bioactive glasses (Sr-MBG), which are able to exert a pro-osteogenic effect by releasing Sr²⁺ ions, have been successfully functionalised to provide mixed-charge (NH₃^⊕/COO^⊝) surface groups with anti-adhesive abilities.

EXPERIMENTS

Sr-MBG have been post-synthesis modified by co-grafting hydrolysable short chain silanes containing amino (aminopropylsilanetriol) and carboxylate (carboxyethylsilanetriol) moieties to achieve a zwitterionic zero-charge surface. The final system was then characterised in terms of textural-structural properties, bioactivity, cytotoxicity, pro-osteogenic and anti-adhesive capabilities.

FINDINGS

After zwitterionization the in vitro bioactivity was maintained, as well as the ability to release Sr²⁺ ions which are capable of inducing a mineralization process. Irrespective of their size, Sr-MBG particles did not exhibit any cytotoxicity in pre-osteoblastic MC3T3-E1 up to the concentration of 75 µg/mL. Finally, the zwitterionic Sr-MBGs showed a significant reduction of serum protein adhesion with respect to the pristine ones. These results open promising future expectations in the design of nanosystems which combine pro-osteogenic and anti-adhesive properties.

Extended Release Combination Antibiotic Therapy from a Bone Void Filling Putty for Treatment of Osteomyelitis

In spite of advances in Total Joint Replacements (TJR), infection remains a major concern and a primary causative factor for revision surgery. Current clinical standards treat these osteomyelitis infections with antibiotic-laden poly(methyl methacrylate) (PMMA)-based cement, which has several disadvantages, including inadequate local drug release kinetics, antibiotic leaching for a prolonged period and additional surgical interventions to remove it, etc. Moreover, not all antibiotics (e.g., rifampicin, a potent antibiofilm antibiotic) are compatible with PMMA. For this reason, treatment of TJR-associated infections and related complications remains a significant concern. The objective of this study was to develop a polymer-controlled dual antibiotic-releasing bone void filler (ABVF) with an underlying osseointegrating substrate to treat TJR implant-associated biofilm infections. An ABVF putty was designed to provide sustained vancomycin and rifampicin antibiotic release for 6 weeks while concurrently providing an osseointegrating support for regrowth of lost bone. The reported ABVF showed efficient antibacterial and antibiofilm activity both in vitro and in a rat infection model where the ABVF both showed complete bacterial elimination and supported bone growth. Furthermore, in an in vivo k-wire-based biofilm infection model, the ABVF putty was also able to eliminate the biofilm infection while supporting osseointegration. The retrieved k-wire implants were also free from biofilm and bacterial burden. The ABVF putty delivering combination antibiotics demonstrated that it can be a viable treatment option for implant-related osteomyelitis and may lead to retention of the hardware while enabling single-stage surgery.

Effects of Different Volatile Anesthetics on Cytokine and Chemokine Production After Ischemia-Reperfusion Injury in Patients Undergoing Living-Donor Kidney Transplant

OBJECTIVES

Renal transplant is the treatment of choice for patients with end-stage renal disease. Ischemiareperfusion damage is a major cause of early renal dysfunction during the perioperative period. Ischemic hypoxic damage increases local inflammation, leading to secretion of cytokines and chemokines. Anesthetic conditioning is a widely described strategy to attenuate ischemia-reperfusion injury. Here, we compared the effects of desflurane and sevoflurane on serum proinflammatory cytokines and urine chemokines in living-donor kidney transplant recipients.

MATERIALS AND METHODS

Eighty donor-recipient couples were included in this randomized study. Anesthesia maintenance was provided by desflurane or sevoflurane. Patient demographic characteristics, immunologic data, clinical data, and hemodynamic parameters were recorded. Tumor necrosis factor α, interleukins 2 and 8, chemokines 9 and 10, and serum creatinine levels were studied from pretransplant, posttransplant days 1 and 7, and posttransplant months 1 and 3 sample results. Estimated glomerular filtration rates were calculated. Acute rejection episodes and graft loss within 6 months posttransplant were recorded.

RESULTS

Seventy donor-recipient couples completed the study. There were no significant differences in demographic, immunologic, and clinical data between desflurane and sevoflurane groups (P > .05). Tumor necrosis factor α, interleukin 2, chemokine 9, and chemokine 10 levels were similar preoperatively and on postoperative days 1 and 7 and months 1 and 3 (P > .05). Serum interleukin 8 levels were significantly higher in patients who received sevoflurane on postoperative days 1 (P = .045) and 7 (P = .037). No significant differences were detected in serum creatinine and estimated glomerular filtration rate between groups (P > .05). No graft loss occurred within 6 months posttransplant.

CONCLUSIONS

Although sevoflurane seemed to produce higher interleukin 8 levels posttransplant, both desflurane and sevoflurane had similar effects on posttransplant kidney function. We suggest that both agents have protective effects on ischemic-reperfusion damage in living-donor kidney transplant recipients.

Efficacy of novel nano-hydroxyapatite/polyurethane composite scaffolds with silver phosphate particles in chronic osteomyelitis

Recently, chronic osteomyelitis is still a challenging surgical problem. Unfortunately, the traditional clinical method using bone cement loaded antibiotics is restricted due to its non-biodegradability and limited release of antibiotics. Hydroxyapatite is a good adsorbent with good biocompatibility, an ideal bone repair material, and can avert the requirement for the secondary surgical procedure of removal. In this study, nano-hydroxyapatite combined with a polyurethane containing 3% silver (Ag/n-HA/PU) was synthesized, and investigated for its efficacy of treating chronic bone infection with bone defects. To clarify its silver ions release characteristics, the concentration of the Ag⁺ in the elution was analyzed every day after in vitro deionized water immersion. A chronic osteomyelitis of tibia in rabbit model was established, and 70 New Zealand rabbits were divided into 4 groups, including the blank control group, nano-hydroxyapatite combined with polyurethane (n-HA/PU) implant group, 3% Ag/n-HA/PU group and 10% Ag/n-HA/PU group after debridement. Routine blood tests, radiography, Micro-CT, and histological staining were conducted at 4 days, 3, 6 and 12 weeks post-treatment. The results showed that the released silver from the 3% Ag/n-HA/PU and 10% Ag/n-HA/PU exhibited an initial burst release and followed by a slow controlled release up to 39 days and 42 days respectively. A good repair of bone defects, an appropriate rate of degradation of scaffolds and no significant toxicity were observed in the 3% Ag/n-HA/PU group, indicating the advantages of this novel synthetic scaffold to be a potential option for the treatment of chronic osteomyelitis. A novel nano-composite, nano-hydroxyapatite combined with a polyurethane containing 3% silver (Ag/n-HA/PU) provide controlled release of Ag⁺, illustrated by its abilities of biodegradation, antimicrobial activity, and favorable repair of bone defects in the treatment of chronic osteomyelitis.

Chronic Osteomyelitis after Seven Years Neglected Bone Exposed in 12-Year-Old Boy: A Case Report

BACKGROUND:

Access to modern medicine is still limited in some rural areas in Indonesia. This is mostly due to lack of people’s knowledge and concern for their health, especially in orthopaedic cases. Osteomyelitis is generally described as infection and inflammation of the bone, which results in local bone destruction, necrosis, and apposition of new bone. Chronic post-traumatic osteomyelitis (CPTO) is a complex condition and one of the most challenging problems in orthopaedic surgery that cause considerable morbidity.

CASE PRESENTATION:

We present a case of chronic post-traumatic osteomyelitis with radial nerve injury, in which radical surgical debridement and broad-spectrum antibiotic administration were done. A 12-year-old boy with a history of falling from the three-meter-high tree had swollen, deformed, and neglected humerus bone exposed. After stabilisation in the emergency room, surgical limb amputation was scheduled, yet the family refused this medical care and chose debridement instead.

CONCLUSION:

This case is an important addition to the literature about chronic post-traumatic osteomyelitis with neglected bone exposed and the lacking of society’s concern in regards to orthopaedic cases.

Short- versus long-course antibiotics in osteomyelitis: A systematic review and meta-analysis

Current practice of long-term antibiotic use in patients with osteomyelitis is controversial. Recent studies showed short-term antibiotic use to be non-inferior to long-term use, but the results of these studies have been inconsistent. In this review, the PubMed and Embase databases were searched from inception through to June 2018 for randomised controlled trials (RCTs), cohort studies or case-control studies comparing two different durations of antibiotic use. Short antibiotic courses were defined as antibiotics administered for a shorter period than the recommended 4-6 weeks. A random-effects model was used to calculate summary odds ratios (ORs) of treatment failure in patients treated with short-course antibiotics compared with long-course antibiotics. A total of 15 articles (5 RCTs and 10 observational studies) and 3598 patients were included. The overall OR of treatment failure in patients receiving short-course antibiotics was 1.50 [95% confidence interval (CI) 0.97-2.34]. Subgroup analysis revealed that a short course of antibiotic treatment was associated with an increased treatment failure rate in vertebral osteomyelitis (OR = 2.06, 95% CI 1.18-3.57) while having a similar rate to a long antibiotic course in acute osteomyelitis of childhood (OR = 1.86, 95% CI 0.75-4.64). Meta-regression found a higher proportion of Staphylococcus aureus infection was related to a higher risk of treatment failure in patients with vertebral osteomyelitis (Coef. = 4.996; P = 0.032). Short-course antibiotics are safe and effective in children with acute osteomyelitis. Long-course antibiotics may still be preferred in vertebral osteomyelitis, especially in patients with S. aureus infection.

Factors predictive of relapse in adult bacterial osteomyelitis of long bones

Background

Osteomyelitis is a difficult-to-cure infection with a high relapse rate despite combined medical and surgical therapies. Some severity factors, duration of antimicrobial therapy and type of surgical procedure might influence osteomyelitis relapse.

Methods

116 patients with osteomyelitis were followed for ≥1 year after hospital discharge. Demographic, microbiological and clinical data, eight severity factors and treatment (surgical and antibiotic) were analyzed.

Results

Mean age was 53 years and 74.1% were men. Tibia (62.1%) and S. aureus (58.5%) were the most commonly involved bone and bacteria, respectively. Mean follow-up was 67.1 months. Forty-six patients underwent bone debridement, 61 debridement plus flap coverage and 9 antimicrobial therapy only. Twenty-six patients (22.4%) relapsed, at a mean of 11.2 months since hospital discharge. Duration > 3 months (p = 0.025), number of severity factors (P = 0.02) and absence of surgery (P = 0.004) were associated with osteomyelitis relapse in the univariate analysis. In the Cox regression analysis, osteomyelitis duration > 3 months (P = 0.012), bone exposure (P = 0.0003) and type of surgery (P < 0.0001) were associated with relapse. Regarding the surgical modalities, bone debridement with muscle flap was associated with better osteomyelitis outcomes, as compared with no surgery (P < 0.0001) and debridement only (P = 0.004).

Conclusions

Osteomyelitis extending for > 3 months, bone exposure and treatment other than surgical debridement with muscular flap are risk factors for osteomyelitis relapse.

An Additive to PMMA Bone Cement Enables Postimplantation Drug Refilling, Broadens Range of Compatible Antibiotics, and Prolongs Antimicrobial Therapy

Poly(methyl methacrylate) (PMMA) bone cement is used in several biomedical applications including as antibiotic-filled beads, temporary skeletal spacers, and cement for orthopedic implant fixation. To mitigate infection following surgery, antibiotics are often mixed into bone cement to achieve local delivery. However, since implanted cement is often structural, incorporated antibiotics must not compromise mechanical properties; this limits the selection of compatible antibiotics. Furthermore, antibiotics cannot be added to resolve future infections once cement is implanted. Finally, delivery from cement is suboptimal as incorporated antibiotics exhibit early burst release with most of  the drug remaining permanently trapped. This prolonged subtherapeutic dosage drives pathogen antibiotic resistance. To overcome these limitations of antibiotic-laden bone cement, insoluble cyclodextrin (CD) microparticles are incorporated into PMMA to provide more sustained delivery of a broader range of drugs, without impacting mechanics. PMMA formulations with and without CD microparticles are synthesized and filled with one of three antibiotics and evaluated using zone of inhibition, drug release, and compression studies. Additionally, the ability of PMMA with microparticles to serve as a refillable antibiotic delivery depot is explored. Findings suggest that addition of CD microparticles to cement promotes postimplantation antibiotic refilling and enables incorporation of previously incompatible antibiotics while preserving favorable mechanical properties.

Bacterial osteomyelitis: microbiological, clinical, therapeutic, and evolutive characteristics of 344 episodes

OBJECTIVE

Osteomyelitis is a difficult-to-cure infection, with high relapse rate despite adequate therapy. Large published osteomyelitis series in adults are rare.

METHODS

A total of 344 adult osteomyelitis patients were studied and followed > 12 months after hospital discharge. Demographic, microbiological, clinical, therapeutic and outcome data were analyzed.

RESULTS

Mean age was 52.5 ± 18.3 years and 233 (67.7%) were male. Main osteomyelitis types were post-surgical (31.1%), post-traumatic (26.2%) and hematogenous (23%). Tibia (24.1%) and femur (21.8%), and methicillin-susceptible S. aureus (29.6%) were the most commonly involved bone and bacteria, respectively. Median follow-up was 12.0 (IQR 0-48) months. Inflammatory markers were increased in 73.6%. Overall, patients were treated by IV and oral routes with one (IV: 44.5%, oral: 26.7%), two (IV: 30.1%, oral: 21.8%) or ≥ 2 (IV: 15.2%, oral: 6.1%) antibiotics. Median duration on IV/oral antimicrobials was 28.0 (IQR 24-28) and 19.5 (IQR 4-56) days, respectively. Anti-staphylococcal β-lactams cloxacillin/cefazolin (19.2%) and ciprofloxacin (5.5%) were the most frequently used IV and orally, respectively. Overall 234 (68.0%) underwent surgery, 113 (32.8%) debridement, 97 (27.4%) debridement + muscle flap and 24 (7%) amputation. At the end of follow-up 208 patients (60.6%) did not have relapsed. Operated patients had significantly less relapses (p<0.0001). A total of 23 (6.7%) died, 11 (3.2%) by infectious complications and 48 (14%) were lost in the follow-up.

CONCLUSIONS

Osteomyelitis is due to different causes complicating its therapy. Risk factors or causal microorganism could influence its treatment and outcome. Aggressive surgery along with adequate antimicrobial therapy are mandatory for cure.

Prosthetic Joint Infections: an Update

PURPOSE OF REVIEW

Prosthetic joint infection (PJI) is a rare but serious complication that is frequently misdiagnosed. We aimed to highlight the nuances of PJI diagnosis and antimicrobial therapies and provide clarity in key areas of management.

RECENT FINDINGS

Current research in PJI centers on a potential role for diagnostic biomarkers, molecular techniques, and implant sonication to reduce culture-negativity rates. The optimal duration of antimicrobial therapy remains controversial. A high clinical index of suspicion for PJI combined with data from multiple preoperative and intraoperative tests enables timely diagnosis and treatment. Biomarkers, molecular methods, and implant sonication are currently adjunctive to traditional diagnostic techniques. Shorter courses of antimicrobial therapies as well as the role of chronic suppressive therapy need confirmation by randomized controlled trials. Existing practices for preoperative dental prophylaxis and treatment of asymptomatic bacteriuria warrant revision based on evidence arguing against risk for PJI.

Multifunctional pH sensitive 3D scaffolds for treatment and prevention of bone infection

Multifunctional-therapeutic three-dimensional (3D) scaffolds have been prepared. These biomaterials are able to destroy the S. aureus bacterial biofilm and to allow bone regeneration at the same time. The present study is focused on the design of pH sensitive 3D hierarchical meso-macroporous 3D scaffolds based on MGHA nanocomposite formed by a mesostructured glassy network with embedded hydroxyapatite nanoparticles, whose mesopores have been loaded with levofloxacin (Levo) as antibacterial agent. These 3D platforms exhibit controlled and pH-dependent Levo release, sustained over time at physiological pH (7.4) and notably increased at infection pH (6.7 and 5.5), which is due to the different interaction rate between diverse Levo species and the silica matrix. These 3D systems are able to inhibit the S. aureus growth and to destroy the bacterial biofilm without cytotoxic effects on human osteoblasts and allowing an adequate colonization and differentiation of preosteoblastic cells on their surface. These findings suggest promising applications of these hierarchical MGHA nanocomposite 3D scaffolds for the treatment and prevention of bone infection.

STATEMENT OF SIGNIFICANCE

Multifunctional 3D nanocomposite scaffolds with the ability for loading and sustained delivery of an antimicrobial agent, to eliminate and prevent bone infection and at the same time to contribute to bone regeneration process without cytotoxic effects on the surrounding tissue has been proposed. These 3D scaffolds exhibit a sustained levofloxacin delivery at physiological pH (pH 7.4), which increasing notably when pH decreases to characteristic values of bone infection process (pH 6.7 and pH 5.5). In vitro competitive assays between preosteoblastic and bacteria onto the 3D scaffold surface demonstrated an adequate osteoblast colonization in entire scaffold surface together with the ability to eliminate bacteria contamination.

Amine-Functionalized Mesoporous Silica Nanoparticles: A New Nanoantibiotic for Bone Infection Treatment

This manuscript reports an effective new alternative for the management of bone infection by the development of an antibiotic nanocarrier able to penetrate bacterial biofilm, thus enhancing antimicrobial effectiveness. This nanosystem, also denoted as “nanoantibiotic”, consists in mesoporous silica nanoparticles (MSNs) loaded with an antimicrobial agent (levofloxacin, LEVO) and externally functionalized with N-(2-aminoethyl)-3- aminopropyltrimethoxysilane (DAMO) as targeting agent. This amine functionalization provides MSNs of positive charges, which improves the affinity towards the negatively charged bacteria wall and biofilm. Physical and chemical properties of the nanoantibiotic were studied using different characterization techniques, including Xray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption porosimetry, elemental chemical analysis, dynamic light scattering (DLS), zeta (ζ)-potential and solid-state nuclear magnetic resonance (NMR). “In vial” LEVO release profiles and the in vitro antimicrobial effectiveness of the different released doses were investigated. The efficacy of the nanoantibiotic against a S. aureus biofilm was also determined, showing the practically total destruction of the biofilm due to the high penetration ability of the developed nanosystem. These findings open up promising expectations in the field of bone infection treatment.

Drug delivery systems functionalized with bone mineral seeking agents for bone targeted therapeutics

The systemic administration of drugs to treat bone diseases is often associated with poor uptake of the drug in the targeted tissue, potential systemic toxicity and suboptimal efficacy. In order to overcome these limitations, many micro- and nano-sized drug carriers have been developed for the treatment of bone pathologies that exhibit specific affinity for bone. Drug carriers can be functionalized with bone mineral seekers (BMS), creating a targeted drug delivery system (DDS) which is able to bind to bone and release therapeutics directly at the site of interest. This class of advanced DDS is of tremendous interest due to their strong affinity to bone, with great expectation to treat life-threatening bone disorders such as osteomyelitis, osteosarcoma or even osteoporosis. In this review, we first explain the mechanisms behind the affinity of several well-known BMS to bone, and then we present several effective approaches allowing the incorporation BMS into advanced DDS. Finally, we report the therapeutic applications of BMS based DDS under development or already established. Understanding the mechanisms behind the biological activity of recently developed BMS and their integration into advanced therapeutic delivery systems are essential prerequisites for further development of bone-targeting therapies with optimal efficacy.

Suppurative Inflammation and Local Tissue Destruction Reduce the Penetration of Cefuroxime to Infected Bone Implant Cavities

Treatment of post-traumatic and implant-associated osteomyelitis (IAO) includes surgical debridement, removal of implants and long-term antibiotic therapy. The success of antibiotic therapy relies not only on activity towards the infecting pathogen, but also on sufficient penetration of the target site. The aim of the present study was to characterize the local pathological changes associated with reduced penetration of cefuroxime to infected bone implant cavities. Previously, reduced penetration of systemically administrated cefuroxime was demonstrated in the implant cavity of 10 pigs with Staphylococcus aureus IAO present for 5 days. In the present study, a comprehensive histopathological characterization of the peri-implant bone tissue was performed and correlated with the reduced penetration of cefuroxime. In two pigs, the levels of oxygen, pyruvate and lactate was estimated in the implant cavity. A peri-implant pathological bone area (PIBA) developed with a width of 1.2 up to 3.8 mm. PIBAs included: (1) suppuration, resulting in destruction of the implant cavity contour, and (2) a non-vascular zone of primarily necrotic bone tissue. A strong negative correlation was seen between PIBA width and cefuroxime area under the concentration time curves (AUC_[0-last]) and peak concentration of cefuroxime (C_max). All metabolic measurements demonstrated hypoxia. In conclusion, subacute suppurative bone inflammation with local tissue destruction can result in decreased penetration of antibiotics and insufficient oxygen supply.

3D scaffold with effective multidrug sequential release against bacteria biofilm

Bone infection is a feared complication following surgery or trauma that remains as an extremely difficult disease to deal with. So far, the outcome of therapy could be improved with the design of 3D implants, which combine the merits of osseous regeneration and local multidrug therapy so as to avoid bacterial growth, drug resistance and the feared side effects. Herein, hierarchical 3D multidrug scaffolds based on nanocomposite bioceramic and polyvinyl alcohol (PVA) prepared by rapid prototyping with an external coating of gelatin-glutaraldehyde (Gel-Glu) have been fabricated. These 3D scaffolds contain three antimicrobial agents (rifampin, levofloxacin and vancomycin), which have been localized in different compartments of the scaffold to obtain different release kinetics and more effective combined therapy. Levofloxacin was loaded into the mesopores of nanocomposite bioceramic part, vancomycin was localized into PVA biopolymer part and rifampin was loaded in the external coating of Gel-Glu. The obtained results show an early and fast release of rifampin followed by sustained and prolonged release of vancomycin and levofloxacin, respectively, which are mainly governed by the progressive in vitro degradability rate of these scaffolds. This combined therapy is able to destroy Gram-positive and Gram-negative bacteria biofilms as well as inhibit the bacteria growth. In addition, these multifunctional scaffolds exhibit excellent bioactivity as well as good biocompatibility with complete cell colonization of preosteoblast in the entire surface, ensuring good bone regeneration. These findings suggest that these hierarchical 3D multidrug scaffolds are promising candidates as platforms for local bone infection therapy.

STATEMENT OF SIGNIFICANCE

The present study is focused in finding an adequate therapeutic solution for the treatment of bone infection based on 3D multifunctional scaffolds, which combines the merits of osseous regeneration and local multidrug delivery. These 3D multidrug scaffolds, containing rifampin, levofloxacin and vancomycin, localized in different compartments to achieve different release kinetics. These 3D multidrug scaffolds displays an early and fast release of rifampin followed by sustained and prolonged release of vancomycin and levofloxacin, which are able to destroy Staphylococcus and Escherichia biofilms as well as inhibit bacteria growth in very short time periods. This new combined therapy approach involving the sequential delivery of antibiofilms with antibiotics constitutes an excellent and promising alternative for bone infection treatment.

Induced membrane technique for the treatment of chronic hematogenous tibia osteomyelitis

Background

Chronic hematogenous osteomyelitis often results from the improper treatment of acute hematogenous osteomyelitis. At present, there is lack of uniform standards for the treatment, and the clinical features of the disease are unclear. The purpose of this study was to explore the clinical efficacy and complications of chronic hematogenous tibia osteomyelitis treated with the induced membrane technique.

Methods

A retrospective analysis of the chronic hematogenous tibia osteomyelitis patients in our department admitted from January 2013 to February 2014 and treated with the induced membrane two-stage surgical technique was performed. The defects were filled with antibiotic-loaded polymethyl methacrylate (PMMA) cement after radical debridement, and bone grafts were implanted to repair the defects after 6 to 8 weeks.

Results

A total of 15 cases were admitted in this study, including 13 men and 2 women with a mean age of 34 years (6 to 51). The mean duration of bone infection was 142 months (3 to 361). All patients were cured with an average follow-up of 25 months (24 to 28). Radiographic bone union occurred in 5.3 months (3 to 8), and full weight bearing occurred in 6.7 months (4 to 10). No recurrence of infection was noted at the last follow-up. Two cases required repeated debridement before grafting due to recurrent infection. One patient had a small bone diameter due to insufficient grafting, and one patient had limitation of knee activity.

Conclusions

The induced membrane technique for the treatment of chronic hematogenous tibia osteomyelitis is an effective and reliable method. Thorough debridement and wound closure at the first stage is essential for infection control as well as sufficient grafting at the second stage to ensure bone union.

Outpatient use of ceftaroline fosamil versus vancomycin for osteoarticular infection: a matched cohort study

OBJECTIVES

There are few convenient intravenous options for long-term outpatient treatment of osteoarticular infection (OAI) and limited effectiveness and safety data exist for this off-label use of ceftaroline. The objective of this study was to describe the long-term effectiveness and safety of ceftaroline for the treatment of OAI.

METHODS

This was a matched retrospective cohort study of patients receiving ceftaroline- or vancomycin-based therapy for OAI in the outpatient setting. Patients were matched according to infection subtype, anatomical site and microbiology. The primary endpoint was 180 day infection-related readmission (IRR). Secondary endpoints included all-cause readmission, time-to-IRR and adverse event incidence.

RESULTS

The final matched cohort consisted of 50 ceftaroline-treated patients and 50 vancomycin-treated patients. The IRR incidence was 22% for ceftaroline patients and 30% for vancomycin patients; OR = 0.66 (95% CI = 0.27-1.62; P = 0.362). There was no significant difference between groups in all-cause readmission or time-to-IRR. Attributable adverse event incidences were 24% and 18% for ceftaroline and vancomycin, respectively. Rash (10%) and nausea (6%) were the most common ceftaroline adverse events, while acute kidney injury (6%) and rash (4%) were the most common vancomycin adverse events.

CONCLUSIONS

Attributable readmission and adverse events were common among patients treated with outpatient intravenous antimicrobials for OAI. This study found no appreciable difference in effectiveness or tolerability between ceftaroline- or vancomycin-treated patients. Although further research will be important to delineate the role of ceftaroline in the management of OAI, data derived from this study may aid clinicians in determining therapy when limited options exist.