Ciprofloxacin inhibition of experimental fracture healing

The role of hematopoiesis in bone repair: an update

PURPOSE OF REVIEW

The repair of bone after injury requires the participation of many different immune cell populations, which are derived from the hematopoietic lineage. The field of osteoimmunology, or the study of the interactions between bone and the immune system, is a growing field with emerging impact on both the basic science and clinical aspects of fracture healing.

RECENT FINDINGS

Despite previous focus on the innate immune system in fracture healing, recent studies have revealed an important role for the adaptive immune system in bone repair. The composition of adaptive and innate immune cell populations present at the fracture site is significantly altered during aging and diet-induced obesity, which may contribute to delayed healing. Recent data also suggest a complicated relationship between fracture repair and systemic inflammation, raising the possibility that immune populations from distant sites such as the gut can impact the bone repair process.

SUMMARY

These findings have important implications for the treatment of fracture patients with antibiotics or anti-inflammatory drugs. Furthermore, the effects of systemic inflammation on fracture repair in the contexts of aging or obesity should be carefully interpreted, as they may not be uniformly detrimental.

The effect of drugs on implant osseointegration- A narrative review

OBJECTIVE

This narrative review aims to investigate the effects of drugs on implant osseointegration, analyzing their potential positive or negative impact on the direct structural and functional connection between bone and load-carrying implants.

BACKGROUND

The review seeks to provide a comprehensive understanding of osseointegration, which refers to the successful integration of an implant with living bone, resulting in no progressive relative movement between them. Exploring the effects of drugs on implant osseointegration is crucial for optimizing outcomes and enhancing patient care in orthopedic implant procedures.

METHODS

Relevant studies on the effects of drugs on implant osseointegration were identified through a literature search. Electronic databases, including PubMed, Embase, and Google Scholar, were utilized, employing appropriate keywords and MeSH terms related to osseointegration, implants, and drug interventions. The search was limited to English studies.

DISCUSSION

This overview presents a detailed analysis of the effects of drugs on implant osseointegration. It explores drugs such as bisphosphonates, teriparatide, statins, angiotensin-converting enzyme inhibitors, beta-blockers, nitrites, and thiazide diuretics as promoters of osseointegration. Conversely, loop diuretics, non-steroidal anti-inflammatory drugs, corticosteroids, cyclosporine A, cisplatin, methotrexate, antibiotics, proton pump inhibitors (PPIs), antiepileptics, selective serotonin reuptake inhibitors (SSRIs), and anticoagulants are discussed as inhibitors of the process. The role of vitamin D3 remains uncertain. The complex relationship between drugs and the biology of implant osseointegration is emphasized, underscoring the need for further in vitro and in vivo studies to validate their effects CONCLUSION: This narrative review contributes to the literature by providing an overview of the effects of drugs on implant osseointegration. It highlights the complexity of the subject and emphasizes the necessity for more extensive and sophisticated studies in the future. Based on the synthesis of the reviewed literature, certain drugs, such as bisphosphonates and teriparatide, show potential for promoting implant osseointegration, while others, including loop diuretics and certain antibiotics, may impede the process. However, additional research is required to solidify these conclusions and effectively inform clinical practice.

Callus γδ T cells and microbe-induced intestinal Th17 cells improve fracture healing in mice

IL-17A (IL-17), a driver of the inflammatory phase of fracture repair, is produced locally by several cell lineages including γδ T cells and Th17 cells. However, the origin of these T cells and their relevance for fracture repair are unknown. Here, we show that fractures rapidly expanded callus γδ T cells, which led to increased gut permeability by promoting systemic inflammation. When the microbiota contained the Th17 cell-inducing taxon segmented filamentous bacteria (SFB), activation of γδ T cells was followed by expansion of intestinal Th17 cells, their migration to the callus, and improved fracture repair. Mechanistically, fractures increased the S1P receptor 1-mediated (S1PR1-mediated) egress of Th17 cells from the intestine and enhanced their homing to the callus through a CCL20-mediated mechanism. Fracture repair was impaired by deletion of γδ T cells, depletion of the microbiome by antibiotics (Abx), blockade of Th17 cell egress from the gut, or Ab neutralization of Th17 cell influx into the callus. These findings demonstrate the relevance of the microbiome and T cell trafficking for fracture repair. Modifications of microbiome composition via Th17 cell-inducing bacteriotherapy and avoidance of broad-spectrum Abx may represent novel therapeutic strategies to optimize fracture healing.

General Considerations About Foot and Ankle Arthrodesis. Any Way to Improve Our Results?

Nonunion and adjacent joint osteoarthritis (OA) are known complications after a fusion procedure, and foot and ankle surgeons are commonly exposed to such disabling complications. Determining who is at risk of developing nonunion is essential to reducing nonunion rates and improving patient outcomes. Several evidenced-based modifiable risk factors related to adverse outcomes after foot and ankle arthrodesis have been identified. Patient-related risk factors that can be improved before surgery include smoking cessation, good diabetic control (HbAc1 <7%) and vitamin D supplementation. Intraoperatively, using less invasive techniques, avoiding joint preparation with power tools, using bone grafts or orthobiologics in more complex cases, high-risk patients, nonunion revision surgeries, and filling in bone voids at the arthrodesis site should be considered. Postoperatively, pain management with NSAIDs should be limited to a short period (<2 weeks) and avoided in high-risk patients. Furthermore, early postoperative weight-bearing has shown to be beneficial, and it does not seem to increase postoperative complications. The incidence of surrounding joint OA after foot and ankle fusion seems to increase progressively with time. Owing to its progression and high probability of being symptomatic, patients must be informed consequently, as they may require additional joint fusions, resulting in further loss of ankle/foot motion. In patients with symptomatic adjacent joint OA and unsatisfactory results after an ankle arthrodesis, conversion to total ankle arthroplasty (TAA) has become a potential option in managing these complex and challenging situations.

Comparative effects of systemic administration of levofloxacin and cephalexin on fracture healing in rats

Objectives

This study aimed to compare the effects of systemic administration of levofloxacin or cephalexin on fracture healing in rats.

Materials and Methods

In this animal study, tibial fractures not requiring fixation were artificially induced in 30 male Wistar albino rats using a 1.1 mm surgical bur. The rats were randomly divided into 6 groups (n=5). Groups 1 and 2 received daily subcutaneous saline injections. Groups 3 and 4 received subcutaneous injections of 25 mg/kg levofloxacin twice daily. Groups 5 and 6 received daily subcutaneous injections of 20 mg/kg cephalexin. The rats in Groups 1, 3, and 5 were sacrificed after 1 week, while the rats in Groups 2, 4, and 6 were sacrificed after 4 weeks. The score of fracture healing was determined through histological assessment of sections from the fracture site according to Perry and colleagues. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests.

Results

The mean score of fracture healing at 4 weeks was significantly higher than that at 1 week in the saline, levofloxacin, and cephalexin groups (P<0.001). At 1 week, no significant difference was noted among the three groups of saline, levofloxacin, and cephalexin in the mean score of fracture healing (P=0.360). However, this difference was significant at 4 weeks (P=0.018), and the mean score in the saline group was significantly higher compared to that in the levofloxacin group (P=0.015).

Conclusion

It is recommended not to prescribe levofloxacin for more than 1 week after surgical management of bone fractures due to its possible adverse effects on fracture healing.

Evolution in the Acute Management of Open Fracture Treatment? Part 1

INTRODUCTION

Despite decades of advancement in wound debridement, prophylactic antibiotic therapy, fracture stabilization, and soft tissue reconstruction, infection remains a serious complication after open fracture. Inconclusive historical data and new challenges with resistant organisms and antimicrobial stewardship having created a difficult environment within which to develop sound, evidence-based treatment protocols that can be applied universally. The first part of this 2-part series will synthesize the historical perspective along with the current concepts surrounding bacteriology and antibiotic use/stewardship. Part 2 will analyze and summarize the current literature regarding the management of open fracture and prevention of subsequent infection.Numerous authors from Hippocrates to Larrey noted that superior results were obtained with an early aggressive debridement of necrotic tissue after wounding.1-7 Historically, the usual outcome after open fracture was infection, sepsis, amputation, and death before the introduction of antibiotics.8-11 As recently as the first half of the 20th century, surgeons argued that if an appropriate debridement was performed, antibiotics were not necessary and advocated against their routine use over concern for resistant organisms.The current period of open fracture treatment (starting in the 1970s) heralded a more scientific era with critical evaluation of antibiotics, surgical debridement, and the development of standardized evidence-based protocols. This era began with 3 classic articles by Patzakis and Gustilo that, to this day, remain central to the discussion of infection prevention after open fractures.12-14.

LEVEL OF EVIDENCE

Therapeutic Level V. See Instructions for Authors for a Complete description of levels of evidence.

In situ functionalizing calcium phosphate biomaterials with curcumin for the prevention of bacterial biofilm infections

This study developed a novel bioactive bone substitute (hydroxyapatite, HA) with improved anti-biofilm activity by functionalizing with curcumin (anti-biofilm compound) which provide sufficient flux of curcumin concentration for 14 days. The released curcumin acts to inhibit biofilm formation and control the number of viable planktonic cells simultaneously. To prepare curcumin-functionalized HA, different concentrations of curcumin (up to 3% w/v) were added simultaneously during the precipitation process of HA. The highest loading (50 mg/g HA) of curcumin onto HA was achieved with 2% w/v of curcumin. Physicochemical characterizations of curcumin-functionalized HA composites revealed that curcumin was successfully incorporated onto HA. Curcumin was sustainably released over 14 days, while higher curcumin release was observed in acidic condition (pH 4.4) compared to physiological (pH 7.4). The cytotoxicity assays revealed that no significant difference on bone cells growth on curcumin-functionalized HA and non-functionalized HA. Curcumin-functionalized HA was effective to inhibit bacterial cell attachment and subsequent biofilm maturation stages. The anti-biofilm effect was stronger against Staphylococcus aureus compared to Pseudomonas aeruginosa. The curcumin-functionalized HA composite significantly delayed the maturation of S. aureus compared to non-functionalized HA in which microcolonies of cells only begin to appear at 96 h. Up to 3.0 log reduction in colony forming unit (CFU)/mL of planktonic cells was noted at 24 h of incubation for both microorganisms. Thus, in this study we have suggested that curcumin loaded HA could be an alternative antimicrobial agent to control the risk of infections in post-surgical implants.

Development of Zoledronic Acid Containing Biomaterials for Enhanced Guided Bone Regeneration

In recent years, biomaterial-based treatments, also called guided bone regeneration (GBR), which aim to establish a bone regeneration site and prevent the migration of gingival connective tissue and / or peripheral epithelium through the defective area during periodontal surgical procedures have come to the fore. In this report, we have developed a nanoparticle bearing thermosensitive in situ gel formulation of Pluronic F127 and poly(D,L-lactic acid) based membrane to reveal their utilization at GBR by in-vivo applications. In addition, the encouragement of the bone formation in defect area via inhibition of osteoclastic activity is intended by fabrication these biodegradable biomaterials at a lowered Zoledronic Acid (ZA) dose. Both of the developed materials remained stable under specified stability conditions (25 °C, 6 months) and provided the extended release profile of ZA. The in-vivo efficacy of nanoparticle bearing in situ gel formulation, membrane formulation and simultaneous application for guided bone regeneration was investigated in New Zealand female rabbits with a critical size defect of 0.5 × 0.5 cm in the tibia bone for eight weeks. Based on the histopathological findings, lamellar bone and primarily woven bone formations were observed after 8 weeks of post-implantation of both formulations, while fibrosis was detected only in the untreated group. Lamellar bone growth was remarkably achieved just four weeks after the simultaneous application of formulations. Consequently, the simultaneous application of ZA-membrane and ZA-nanoparticles loaded in-situ gel formulations offers enhanced and faster GBR therapy alternatives.

3D additive manufactured composite scaffolds with antibiotic-loaded lamellar fillers for bone infection prevention and tissue regeneration

Bone infections following open bone fracture or implant surgery remain a challenge in the orthopedics field. In order to avoid high doses of systemic drug administration, optimized local antibiotic release from scaffolds is required. 3D additive manufactured (AM) scaffolds made with biodegradable polymers are ideal to support bone healing in non-union scenarios and can be given antimicrobial properties by the incorporation of antibiotics. In this study, ciprofloxacin and gentamicin intercalated in the interlamellar spaces of magnesium aluminum layered double hydroxides (MgAl) and α-zirconium phosphates (ZrP), respectively, are dispersed within a thermoplastic polymer by melt compounding and subsequently processed via high temperature melt extrusion AM (~190 °C) into 3D scaffolds. The inorganic fillers enable a sustained antibiotics release through the polymer matrix, controlled by antibiotics counterions exchange or pH conditions. Importantly, both antibiotics retain their functionality after the manufacturing process at high temperatures, as verified by their activity against both Gram + and Gram - bacterial strains. Moreover, scaffolds loaded with filler-antibiotic do not impair human mesenchymal stromal cells osteogenic differentiation, allowing matrix mineralization and the expression of relevant osteogenic markers. Overall, these results suggest the possibility of fabricating dual functionality 3D scaffolds via high temperature melt extrusion for bone regeneration and infection prevention.

HISTOPATHOLOGICAL AND BIOMECHANICAL INVESTIGATION OF THE EFFECT OF MOMORDICA CHARANTIA ON FRACTURE HEALING, KIDNEY, AND LIVER: AN EXPERIMENTAL RAT MODEL

Momordica charantia (MC) is a plant belonging to the family Cucurbitaceae. MC has antidiabetic, antibacterial, antioxidant, antimutagenic, antiulcerative, antiinflammatory and antilipidemic effects. However, information on the effect of MC on fracture union is lacking. This study aimed to examine the effect of MC on fracture union histopathologically and biomechanically. A total of 42 male Wistar-Albino rats were randomly divided into 3 groups, 14 in each group. A diaphyseal fracture was created on the right tibia of all rats. All fractures were fixed with a Kirschner (K) wire. The rats in Group I did not undergo any further procedures (Control group). Group II rats were treated with 0.9% saline oral gavage at a dose of [Formula: see text]L/day for 28 days [Saline (S) group]. The rats in Group III were given 300[Formula: see text]mg/kg MC extract per day, dissolved in [Formula: see text]L 0.9% saline by oral gavage for 28 days [MC (Extract) group]. After 28 days, all rats were sacrificed. Each group was randomly divided into two subgroups. The histopathological examination was performed on the right tibia of rats in the first subgroup and the biomechanical examination in the second subgroup. The kidneys and livers of all rats were evaluated histopathologically. Fracture union was significantly better in the Extract group compared with the Control and S groups histopathologically. The fracture inflammation values were lower in the Extract group than in the other groups. No statistically significant difference was found between the groups in terms of possible side effects to kidneys and livers. In terms of biomechanics, fracture union was significantly better in the Extract group compared with the Control and S groups except yield displacement values. MC had a positive effect on fracture union histopathologically and biomechanically.

Comparison between Tonifying Kidney Yang and Yin in Treating Segmental Bone Defects Based on the Induced Membrane Technique: An Experimental Study in a Rat Model

Tonifying kidney therapy consisting of tonifying kidney yang and yin is the basic principle of Chinese medicine in treating segmental bone defects (SBDs). Previous studies have demonstrated the presence of the differences between tonifying kidney yang and yin in bone metabolism of osteoporosis and distraction osteogenesis models. However, whether the difference between the two tonifying kidney methods in bone repair for the induced membrane (IM) technique occurs or what is the difference remain unclear. Angiogeneic-osteogenic coupling plays an important role in bone repair and the induced membrane couples angiogenesis with the later osteogenesis during the IM process. This study aimed at investigating the effects of tonifying kidney yang (total flavonoids of Rhizoma Drynariae, TFRD) and yin (plastrum testudinis extract, PTE) on angiogenesis and osteogenesis in the IM-treated SBDs. Rats of 6 mm tibia bone defect model treated with IM were divided into five groups: the control group, the model group, the tonifying kidney yang group (TFRD-treated group), the tonifying kidney yin group (PTE-treated group), and the western medicine group. At 4 weeks after insertion of the polymethylmethacrylate (PMMA), three caudal vertebrae from the tail in each rat were implanted into the 6 mm defect gap. Radiographical, histological, immunohistochemical, and immunofluorescent analyses were performed to assess bone and vessel formation at 4 or 12 weeks after insertion of the PMMA, respectively. Our results revealed that TFRD and PTE were beneficial to both angiogenesis and osteogenesis. TFRD exerted a better effect on angiogenesis than PTE and achieved a better result in stage 1 rather than in stage 2 of IM, whereas PTE was superior to TFRD in osteogenesis and achieved a better result in stage 2 instead of stage 1. Collectively, these findings elucidated the beneficial effects of tonifying kidney yang and yin on angiogenesis and osteogenesis of SBD repair during the IM process, as well as the difference that tonifying kidney yang surpasses tonifying kidney yin in angiogenesis while tonifying kidney yin outperforms tonifying kidney yang in osteogenesis, which suggests that the combination between the application of tonifying kidney yang method in stage 1 of IM and tonifying kidney yin method in stage 2 may achieve better repair efficiency.

Antibiotic Prophylaxis in Open Fractures: Evidence, Evolving Issues, and Recommendations

Open fractures are often associated with high-energy trauma and have an increased risk of infection because of surrounding soft-tissue damage and the introduction of environmental contaminants that may communicate with the fracture site. The Gustilo-Anderson classification of open fractures has been used to guide prophylactic antibiotic therapy because different types of open fracture have been shown to have varying rates of surgical site infections with different combinations of pathogens. Prophylactic treatment with various classes of antibiotics, including penicillins and cephalosporins, aminoglycosides, and fluoroquinolones, has evolved over the past half century. More recently, broader spectrum agents including monobactams and glycopeptides have been used for additional coverage. Duration of antibiotic therapy remains variable between institutions, and antibiotic choice is not standardized. Coverage for nosocomial and multidrug-resistant organisms is an ongoing area of clinical research.

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

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

Effects of NSAID use on bone healing: A meta-analysis of retrospective case–control and cohort studies within clinical settings

Introduction

This meta-analysis aims to determine whether non-steroidal anti-inflammatory drug (NSAID) use is significantly associated with adverse bone healing outcomes within clinical settings, including trauma and elective spine settings. It will also explore bone healing outcomes with the type, route, dosage and duration of NSAID exposure and aims to demonstrate the effects of various other confounding factors on bone healing outcomes.

Methods

Electronic databases including MedLine, Embase and Cochrane were searched from January 1975 to December 2017. A distinct analysis of observational long bone and spine studies in adult populations was performed, assessing the effects of NSAID exposure on bone healing. Studies from paediatric population and randomised trials also underwent separate assessment in the synthesis. Meta-analysis was conducted in compliance with QUORUM and PRISMA guidelines.

Results

Quantitative assessment of observational studies suggested a significant risk of bone healing complications with NSAID exposure across each clinical group: long bone (p = 0.0004) and spine (p = 0.02). Analysis of paediatric studies revealed a non-significant association of poor outcomes with NSAID use (p = 0.36), while assessment of randomised trials demonstrated a statistically significant risk of complications following NSAID administration (p = 0.04). Meta-regression further suggested smoking to be a substantial confounder associated with adverse bone healing outcomes (p < 0.00001).

Conclusion

Inclusion of only fair and moderate-quality retrospective cohort and case–control studies in the current synthesis limits the clinical application of its findings and therefore warrants the need for further research. Thus, attempts to conduct high-quality prospective cohort and randomised trials to study the effects of NSAID use on bone healing would be very helpful and will provide a basis for more extensive research in future.

Vancomycin powder for the prevention of surgical site infection in posterior elective spinal surgery

OBJECTIVE

To assess the effectiveness and safety of vancomycin powder as surgical site infection (SSI) prophylaxis in posterior bilateral elective spinal surgery.

MATERIALS AND METHODS

Single-center quasi-experimental pre and postintervention comparative cohort study. The post-intervention group received standard intravenous antibiotic prophylaxis plus 1g of vancomycin powder into the surgical field before wound closure, and the pre-intervention group only the intravenous prophylaxis.

RESULTS

150 patients were included in each group. Twelve SSI (7 superficial and 5 deep) occurred in the post-intervention group and 16 SSI (7 superficial and 9 deep) in the pre-intervention group. The risk of deep SSI decreased from 6.0% to 3.3% (OR 0,54, 95%CI 0.17-1.65, p=0.411) with vancomycin powder. The percentage of deep SSI due to gram negative-positive germs were 80%-20% and 33%-67% for the post- and pre-intervention groups, respectively (p=0.265). No local or systemic adverse effects occurred attributable to vancomycin powder.

CONCLUSION

In posterior elective spinal surgery, prophylaxis with vancomycin powder did not result in a significantly reduced incidence of superficial and deep SSI. There was a trend towards a higher incidence of deep SSI caused by gram negative microorganisms among those treated with vancomycin.

Evaluation of infection rates with narrow versus broad-spectrum antibiotic regimens in civilian gunshot open-fracture injury

INTRODUCTION

Civilian gunshot open-fracture injuries portray a significant health burden to patients. Use of antibiotics is endorsed by guideline recommendations for the prevention of post-traumatic infections, however, antimicrobial selection and their associated outcomes remains unclear. Therefore, we sought to compare infectious and other clinical outcomes between three antimicrobial cohorts in patients with gunshot-related fractures requiring operative intervention.

MATERIALS AND METHODS

Patients were identified by retrospectively querying the University of Kentucky Trauma Registry for gunshot wound victims. A narrow regimen, an expanded gram-negative regimen, and a regimen containing a fluoroquinolone antimicrobial were identified for comparison. The primary outcome was a composite of infections at or before 14 days of hospitalization. Secondary endpoints included hospital length of stay, incidence of multidrug resistant bacteria and methicillin-resistant Staphylococcus aureus colonization, number of drug-related adverse events, number of Clostridium difficile infections, and 30-day mortality.

RESULTS

252 patients were selected for inclusion: 126 in the narrow regimen, 49 in the expanded gram-negative regimen, and 77 in the fluoroquinolone-based regimen. There were no statistical differences in the primary endpoint of early infectious outcomes between groups (p = 0.1797). The expanded gram-negative regimen was associated with increased hospital length of stay, and increased incidence of multi-drug resistant bacteria and methicillin-resistant Staphylococcus aureus colonization. There were no statistically significant differences in any of the remaining secondary endpoints.

CONCLUSION

In this study evaluating civilian gunshot trauma, broad spectrum antibiotic coverage was not associated with improvements in post-traumatic infections. A randomized trial is needed to confirm these results.

In vivo hydroxyapatite scaffold performance in infected bone defects

Critically sized bone defects are often compounded by infectious complications. The standard of care consists of bone autografts with systemic antibiotics. These injuries and treatments lead to donor site morbidity, antibiotic resistant strains of bacteria, and often end stage amputation. This study proposes an alternative to the autograft using a porous, hydroxyapatite (HA) scaffold evaluated with and without infection and antibiotics. Twenty-four New Zealand white rabbits received either our HA scaffold or a pulverized autograft (PBA) within a surgically created critical-sized defect in the femur. The two grafts were evaluated in either septic or aseptic defects and with or without antibiotic treatment. The HA scaffolds were characterized with micro computed tomography. Post-euthanasia, micro computed tomography, histology, and white blood cells component analysis were completed. The HA had significantly greater (p < .001) mineralization to total volume than the PBA groups with 27.56% and 14.88%, respectively, and the septic HA groups were significantly greater than the aseptic groups both with and without antibiotics (p = .016). The bone quality denoted by bone mineral density was also significantly greater (p < .001) in the HA groups (67.01 ± 0.38 mgHA/cm³ ) than the PBA groups (64.66 ± 0.85 mgHA/cm³ ). The HA scaffold is a viable alternative to the bone autograft in defects with and without infection as shown by the quality and quantity of bone.

Calcium Phosphate Spacers for the Local Delivery of Sitafloxacin and Rifampin to Treat Orthopedic Infections: Efficacy and Proof of Concept in a Mouse Model of Single-Stage Revision of Device-Associated Osteomyelitis

Osteomyelitis is a chronic bone infection that is often treated with adjuvant antibiotic-impregnated poly(methyl methacrylate) (PMMA) cement spacers in multi-staged revisions. However, failure rates remain substantial due to recurrence of infection, which is attributed to the poor performance of the PMMA cement as a drug release device. Hence, the objective of this study was to design and evaluate a bioresorbable calcium phosphate scaffold (CaPS) for sustained antimicrobial drug release and investigate its efficacy in a murine model of femoral implant-associated osteomyelitis. Incorporating rifampin and sitafloxacin, which are effective against bacterial phenotypes responsible for bacterial persistence, into 3D-printed CaPS coated with poly(lactic co-glycolic) acid, achieved controlled release for up to two weeks. Implantation into the murine infection model resulted in decreased bacterial colonization rates at 3- and 10-weeks post-revision for the 3D printed CaPS in comparison to gentamicin-laden PMMA. Furthermore, a significant increase in bone formation was observed for 3D printed CaPS incorporated with rifampin at 3 and 10 weeks. The results of this study demonstrate that osteoconductive 3D printed CaPS incorporated with antimicrobials demonstrate more efficacious bacterial colonization outcomes and bone growth in a single-stage revision in comparison to gentamicin-laden PMMA requiring a two-stage revision.

Topical rifampin powder for orthopaedic trauma part II: Topical rifampin allows for spontaneous bone healing in sterile and contaminated wounds

Infectious complications can reduce fracture healing rate. Broad spectrum antibiotics are commonly administered to prevent and treat musculoskeletal infections. Local antibiotics are applied to the wound site to increase therapeutic concentrations without increasing systemic toxicity, however, may hinder local tissue recovery. Rifampin has been shown to eradicate mature Staphylococcal biofilms and its use proven for treating musculoskeletal infections. In this study, a spontaneously healing defect model in a rat was used to investigate the impact rifampin powder has on endogenous bone healing in both a sterile and contaminated wound. No significant differences were identified in bone volume fraction via microcomputed tomography, radiological scoring, or histology between an empty defect and animals that received vancomycin or rifampin powder in a sterile wound. When applied to a contaminated musculoskeletal wound, the rifampin powder had significantly greater bone formation compared to the control, as measured by microcomputed tomography, plain radiology, and histology. In addition, the animals treated with rifampin powder had reduced bacteria, reduced white blood cell count and reduced number of clinical indications of infection. Interestingly, while the vancomycin group still displayed signs of infection via quantitative microbiology, plain radiology, and histology, there was significant bone formation within the defect and reduction of systemic signs of infection. We demonstrated that the use of rifampin powder allows bone to heal in both a sterile and contaminated model of musculoskeletal infection. To our knowledge, this is the first time the direct impact of local antibiotics on bone healing has been investigated. Published 2018. This article is a U.S. Government work and is in the public domain in the USA. J Orthop Res 36:3142-3150, 2018.

Do local antibiotics reduce periprosthetic joint infections? A retrospective review of 744 cases

Periprosthetic joint infections (PJI) are uncommon but not rare and have significant morbidity and financial implications. Local antibiotics have been used successfully in other areas of orthopedics to reduce postoperative infections, but this method has not been proven in total joint arthroplasty (TJA). Beginning January 1, 2014, our primary investigators began using surgical site lavage with providone-iodine solution and administering 2 g of vancomcyin powder in the surgical wound prior to capsule closure for all primary and revision total hip and knee arthroplasties. We performed a retrospective chart review of patients two years prior to this date and two years after to compare occurrence of PJI. The groups were broken down into patients who received local antibiotics versus those who did not. The groups were further broken down by type of surgery performed; primary or revision total hip or knee arthroplasty. Administration of local antibiotics was preventative for PJI only in the primary total knee arthroplasty group (aOR = 0.28, 0.09-0.89). Administration of local antibiotics trended towards a preventative effect for PJI in the other groups but was not statistically significant. Patients receiving local antibiotics had similar blood urea nitrogen and creatinine levels postoperatively compared to the no antibiotics group indicating minimal systemic effects of local vancomycin powder. While the use of local antibiotics may prevent PJI, more data is required especially in the revision arthroplasty groups.

Treatment of critical-sized bone defects: clinical and tissue engineering perspectives

Critical-sized bone defects are defined as those that will not heal spontaneously within a patient's lifetime. Current treatment options include vascularized bone grafts, distraction osteogenesis, and the induced membrane technique. The induced membrane technique is an increasingly utilized method with favorable results including high rates of union. Tissue engineering holds promise in the treatment of large bone defects due to advancement of stem cell biology, novel biomaterials, and 3D bioprinting. In this review, we provide an overview of the current operative treatment strategies of critical-sized bone defects as well as the current state of tissue engineering for such defects.

Histopathological comparison of bone healing effects of endonasal and percutaneous lateral osteotomy methods in rabbit rhinoplasty model

Introduction

Lateral osteotomy is mainly performed either endonasally or percutaneously in rhinoplasty which is a frequently performed operation for the correction of nasal deformities. Both techniques have both advantages and disadvantages relative to each other.

Objective

The aim of this study was to compare the histopathological effects of endonasal and percutaneous osteotomy techniques performed in rhinoplasty on bone healing and nasal stability in an experimental animal model.

Methods

Eight one year-old New Zealand white rabbits were included. Xylazine hydrocloride and intramuscular ketamine anesthesia were administered to the rabbits. Endonasal osteotomy (8 bones) was performed in Group 1 (n = 4), and percutaneous osteotomy (8 bones) in Group 2 (n = 4). One month later the rabbits were sacrificed. Bone healing of the rabbits was staged according to the bone healing score of Huddleston et al. In both groups, nasal bone integrity was assessed subjectively.

Results

In the percutaneous osteotomy group, Grade 1 bone healing was observed in two samples (25%), Grade 2 bone healing in two samples (25%), Grade 3 bone healing in four samples (50%). In the endonasal osteotomy group, Grade 1 bone healing was observed in 6 samples (75%) and Grade 2 bone healing was observed in 2 samples (25%). In the percutaneous group, fibrous tissue was observed in 2, predominantly fibrous tissue and a lesser amount of cartilage was observed in 2 and an equal amount of fibrous tissue and cartilage was observed in 4 samples. In the endonasal group, fibrous tissue was observed in 6 samples, and predominantly fibrous tissue with a lesser amount of cartilage was observed in 2 samples. In both groups, when manual force was applied to the nasal bones, subjectively the same resistance was observed.

Conclusion

Percutaneous lateral osteotomy technique was found to result in less bone and periost trauma and better bone healing compared to the endonasal osteotomy technique.

Impact of Body Mass Index and Bacterial Resistance in Osteomyelitis after Antibiotic Prophylaxis of Open Lower-Extremity Fractures

BACKGROUND

We investigated the clinical effectiveness of antimicrobial prophylaxis in lower-extremity open fractures following the Eastern Association for the Surgery of Trauma Guidelines.

METHODS

This observational, retrospective, single-center study included adults with lower-extremity open fractures of the ankle, tibia, fibula, or femur. The primary endpoint was the incidence of osteomyelitis within 12 months of the fracture. Secondary endpoint comparisons were the time of antibiotic initiation and drug selection.

RESULTS

A total of 90 patients were included. Patients suffered from Gustilo and Anderson grades I (14%), II (54.7%), and III (31.3%) fractures. Almost all patients received cefazolin (98%). Among grade III fractures, 59.3% (16/27) of patients received additional gram-negative coverage as recommended by the guidelines. The osteomyelitis rate was 8.9%. There was no difference in osteomyelitis rates among patients with grade III fractures who received or did not receive additional gram-negative coverage: 18.8% (3/16) and 0 (0/11) (p = 0.248), respectively. There was no correlation between median antibiotic start time or antibiotic stop time after closure and the development of osteomyelitis, respectively. Resistant organisms caused 50% (4/8) of the osteomyelitis cases. On univariate analysis, obesity had the most significant association with osteomyelitis (p = 0.026).

CONCLUSIONS

Bacterial resistance was common among cases of osteomyelitis in our cohort. Obesity was associated with a higher rate of osteomyelitis.

Mechanisms of bone response to injury

Bone, despite its relatively inert appearance, is a tissue that is capable of adapting to its environment. Wolff’s law, first described in the 19th century, describes the ability of bone to change structure depending on the mechanical forces applied to it. The mechanostat model extended this principle and suggested that the amount of strain a bone detects depends on bone strength and the amount of muscle force applied to the bone. Experimental studies have found that low-magnitude, high-frequency mechanical loading is considered to be the most effective at increasing bone formation. The osteocyte is considered to be the master regulator of the bone response to mechanical loading. Deformation of bone matrix by mechanical loading is thought to result in interstitial fluid flow within the lacunar–canalicular system, which may activate osteocyte mechanosensors, leading to changes in osteocyte gene expression and ultimately increased bone formation and decreased bone resorption. However, repetitive strain applied to bone can result in microcracks, which may propagate and coalesce, and if not repaired predispose to catastrophic fracture. Osteocytes are a key component in this process, whereby apoptotic osteocytes in an area of microdamage promote targeted remodeling of the damaged bone. If fractures do occur, fracture repair can be divided into 2 types: primary and secondary healing. Secondary fracture repair is the most common and is a multistage process consisting of hematoma formation and acute inflammation, callus formation, and finally remodeling, whereby bone may return to its original form.

Current management of open fractures: results from an online survey

BACKGROUND

Open fractures are orthopaedic emergencies that carry a high risk for infection, non-union and soft tissue complications. Evidence-based treatment is impeded by the lack of high-quality evidence-based studies. The aim of this investigation was to elucidate the current practice of open fracture management in Germany and to determine major differences in treatment.

METHODS

Surgeons were asked to complete an online questionnaire consisting of 45 items developed by an expert consensus. The first part covered questions on general principles of open fracture management. The second part included questions on soft tissue management, the preferred method of initial surgical stabilisation, microbiological testing, employment of pulsatile lavage and local antibiotics, antibiotic regimen, second-look operations, and blood testing.

RESULTS

Of 653 respondents, 364 (65 %) completed the first part and 314 (48 %) completed the second part of the online survey. 55 % answered that a standard operating procedure for the diagnosis and treatment of patients with open fractures exists in their hospital. Only 25 % leave pre-hospitalisation applied dressings intact until arrival of the patient in the operating room, and 40 % make this decision depending on information provided by pre-hospitalisation emergency personnel. 84 % participants exclude the use of antibiotic-coated implants in the treatment of open fractures. The favoured stabilisation method in Gustilo type I fractures is definitive internal osteosynthesis and primary wound closure for 61 % of respondents. In Gustilo type II (74 %) and type III fractures (93 %), temporary external fixation is preferred. High-pressure pulsatile lavage is used by 22 % responding surgeons in Gustilo type I fractures, 53 % for type II fractures and 67 % for type III fractures.

CONCLUSIONS

Open fracture management differs considerably among surgeons in Germany. Further studies are needed to deliver high-quality evidence concerning primary fracture stabilisation, soft tissue management and second-look operations. Existing evidence-based recommendations for general treatment, antibiotic prophylaxis and soft tissue management should be followed more strictly in clinical practice.

Does Activin Receptor Blockade by Bimagrumab (BYM338) Pose Detrimental Effects on Bone Healing in a Rat Fibula Osteotomy Model?

Bimagrumab (BYM338) is a novel fully human monoclonal antibody that exerts strong promyogenic effects on skeletal muscle by blocking activin type II receptors (ActRII). We investigated whether such blockade of ActRII by bimagrumab manifests any detrimental effect on outcomes of bone healing in a rat fibula osteotomy model. Animals (n = 150) were divided into 11 groups and received weekly treatment with either bimagrumab (10 or 100 mg/kg) or vehicle. Progression and outcomes of bone healing were assessed by lateral radiographs in vivo as well as by peripheral quantitative computed tomography (pQCT), 4-point bending test, and microscopic examination of the excised fibula at Day 29 or later. The radiographic progression of bone healing showed no significant differences between treatment groups in any comparative setting. In 3-month-old animals, pQCT revealed slightly reduced immature callus size and bone mineral content in bimagrumab-treated animals compared with vehicle-treated animals at Day 29 (p < 0.05). There were, however, no differences in mature callus size, bone mineral density, or biomechanical competency. The aforementioned effects on immature callus size were not present when the treatment was initiated 4 weeks post osteotomy or when treating 6-month-old animals. In summary, these findings suggest that there is no major impact of ActRII blockade on overall fracture healing, and delayed treatment initiation can bypass the small and transient effect of the therapy on immature callus formation observed in younger animals. Verification of these findings in humans is the subject of an ongoing clinical trial on elderly hip fracture patients.

Does cefuroxime alter fracture healing in vivo? A micro-computertomographic, biomechanical, and histomorphometric evaluation using a rat fracture model

Cefuroxime is widely used for antibiotic prophylaxis in orthopedic surgery. However, a recent study indicated a dose-dependent reduction in osteoblast function in vitro. Nevertheless, cell culture might not sufficiently imitate the complex process of bone remodeling. As data concerning possible in vivo interactions of cefuroxime on fracture healing are completely missing, we investigated the following hypothesis: Does Cefuroxime impair bone healing in vivo? Therefore, 34 male Wistar rats were randomised to cefuroxime-treated or control groups, a Kirschner wire was inserted into right femora and closed transverse fractures were produced. Twenty-one days later, the structural properties of the fracture callus in the early fracture healing phase were evaluated via a combination of micro-CT (μCT), biomechanics and histology. µCT demonstrated similar values in the cefuroxime and control group (e.g., callus volume: 67.19 ± 14.90 mm³ vs. 55.35 ± 6.74 mm³ , p = 0.12; density: 635.48 ± 14.81 mg HA/cm³ vs. 647.87 ± 13.01 mg HA/cm³ , p = 0.16). Biomechanically, similar values were again determined between the groups, in terms of both maximum load (77.65 ± 41.82 vs. 78.54 ± 20.52, p = 0.95) and stiffness (122.44 ± 81.16 vs. 123.74 ± 60.08, p = 0.97). Histological findings were consistent with the radiographic results. Thus, no relevant differences between the cefuroxime and control groups could be found and the reported negative effects on osteoblasts in vitro were not confirmed in vivo by using standard concentrations of cefuroxime. In conclusion, cefuroxime can reasonably be recommended in a clinical setting as an antibiotic therapy when fracture healing is involved. However, supraphysiological doses were not evaluated, which may be present when cefuroxime is used as an additive to bone cement and released over time. Therefore, future studies should evaluate the in vivo effects of prolonged high cefuroxime doses on implant incorporation. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2282-2291, 2017.

Bacterial contamination of open fractures - pathogens, antibiotic resistances and therapeutic regimes in four hospitals of the trauma network Cologne, Germany

INTRODUCTION

The bacterial contamination of soft tissues and bone in open fractures leads to an infection rate of up to 50%. Pathogens and their resistance against therapeutic agents change with time and vary in different regions. In this work, our aims were to characterize the bacterial spectrum present in open fractures, analyze the bacterial resistance to antibiotic agents and question the EAST guideline recommendations for antibiotic prophylaxis after open fractures in a German Trauma Network.

MATERIALS AND METHODS

We conducted a retrospective cohort study and included all patients with open fractures from 1(st) of January 2011 until the 31(st) of December 2014 in four hospitals of the trauma network cologne. Soft tissue damage was classified according to the Gustilo Anderson classification.

RESULTS

We included 123 patients. Forty-five injuries (37%) were classified I°, 45 (37%) as II° and 33 (27%) as III°. Lower leg (34%) was the most commonly injured location. An antibiotic prophylaxis was administered to 109 patients (89%). In 107 of them (98%) a cephalosporin or cephalosporin combination was given. In 35 of the patients (28%), microbiological samples were taken of the fracture site. Wound cultures were positive in 21 patients (60%). Fifty percent of the bacterial detections occurred in III° fractures. Coagulase negative Staphylococci (COST) were the most frequent pathogens. In II° open fractures one gram-negative strain was isolated. Fewest resistances were seen against quinolones and co-trimoxazole.

DISCUSSION

The recommended EAST guideline prophylaxis would have covered all but one bacterium (97% of positive cultures). One Escherichia coli was found in a II° open fracture and would have been missed. One of the isolated Staphylococci epidermidis and an Enterococcus faecium were resistant against gentamycin and first- and second-generation-cephalosporin's which were used as prophylaxis frequently. However, a regional adaption of the EAST guidelines seems not justified due to the rather low number of cases in our study.

CONCLUSION

The EAST guideline seems to be adequate in a high percentage of cases (97%) in the setting of the trauma network cologne. Further research should be guided at identification of initial open fracture pathogens to improve the efficiency of antibiotic prophylaxis.

Effects of Local Administration of Boric Acid on Posterolateral Spinal Fusion with Autogenous Bone Grafting in a Rodent Model

Spinal fusion is among the most frequently applied spinal surgical procedures. The goal of the present study was to evaluate whether the local administration of boric acid (BA) improves spinal fusion in an experimental spinal fusion model in rats. Currently, there is no published data that evaluates the possible positive effects if the local administration of BA on posterolateral spinal fusion. Thirty-two rats were randomly divided into four independent groups: no material was added at the fusion area for group 1; an autogenous morselized corticocancellous bone graft was used for group 2; an autogenous morselized corticocancellous bone graft with boric acid (8.7 mg/kg) for group 3; and only boric acid was placed into the fusion area for group 4. The L4-L6 spinal segments were collected at week 6, and the assessments included radiography, manual palpation, and histomorphometry. A statistically significant difference was determined between the groups with regard to the mean histopathological scores (p = 0.002), and a paired comparison was made with the Mann-Whitney U test to detect the group/groups from which the difference originated. It was determined that only the graft + BA practice increased the histopathological score significantly with regard to the control group (p = 0.002). Whereas, there was no statistically significant difference between the groups in terms of the manual assessment of fusion and radiographic analysis (respectively p = 0.328 and p = 0.196). This preliminary study suggests that BA may clearly be useful as a therapeutic agent in spinal fusion. However, further research is required to show the most effective dosage of BA on spinal fusion, and should indicate whether BA effects spinal fusion in the human body.

Attitudes of Nigerian orthopaedic surgeons to the use of prophylactic antibiotics

PURPOSE

Inappropriate use of prophylactic antibiotics can increase the rates of surgical site wound infections, lead to the development of resistant organisms and to increased health care costs. Despite widespread knowledge of standard antibiotic prophylaxis protocols (SAPs) in implant surgeries, it is thought that many Nigerian surgeons do not comply. The purpose of this study was to determine the awareness of Nigerian orthopaedic surgeons of SAPs in implant surgeries and their compliance.

METHODS

This was an observational study done using a questionnaire to collect data from orthopaedic surgeons at the National Orthopaedic Association annual conference held at Lokoja, Nigeria in November 2013.

RESULTS

There were 66 respondents divided into 56 consultants and ten surgical residents. Most respondents were aware of standard guidelines for the use of prophylactic antibiotics (86.36 %). Many of them (63.63 %) did not know the average rate of infection following implant surgery in their institutions. Compliance with SAPs was found to be 30.3 %. Compliance was worse among surgeons between 41 and 50 years of age and consultants with between six and ten years of practice.

CONCLUSIONS

Most respondents are aware of standard antibiotic protocols, but do not comply with them. The study also suggests that surgeons with intermediate levels of experience and those between 41 and 50 years of age were most unlikely to comply.

Intrasite vancomycin powder for the prevention of surgical site infection in spine surgery: a systematic literature review

BACKGROUND CONTEXT

Deep surgical site infections (SSIs) following spinal surgery are a significant burden to the patient, patient's family, and the health-care system. Because of increasing pressures to reduce SSIs and control costs, some spine surgeons have begun placing lyophilized vancomycin powder directly into the surgical wound at the conclusion of the procedure. However, the literature supporting this practice remains limited.

PURPOSE

To review the current literature examining the use of prophylactic intrasite vancomycin powder to control SSIs in spinal surgery and determine if any standard recommendations can be made.

STUDY DESIGN

A systematic review.

METHODS

Ovid Medline and PubMed were searched to identify English language articles.

RESULTS

No current guidelines are available for the use of intrasite vancomycin powder in preventing SSIs, and no standard dosage for the drug exists. Based on the limited literature and evidence currently available, there appears to be a protective effect of intrasite vancomycin powder on the incidence of SSI, without evidence of side effects. However, case reports do exist describing the systemic side effects after intrasite vancomycin powder during spine surgery.

CONCLUSIONS

The interpretation of the available evidence supporting the use of intrasite vancomycin powder in surgical wounds is limited, and its extrapolation should be performed with caution. Despite the lack of significant high-quality evidence available in the literature, many surgeons have adopted this practice; anecdotally, it continues to provide protection from infection without apparent significant risk of side effects.

Parameters for lithium treatment are critical in its enhancement of fracture-healing in rodents

BACKGROUND

Lithium, a treatment for bipolar disorder, is not clinically indicated for use in fracture management but has been reported to positively influence bone biology. It is hypothesized that lithium dosing for beneficial effects on bone health may be much lower than the dosing required for psychotropic benefits in patients with bipolar disorder. A preclinical study with a rodent fracture model was utilized to best define the lowest effective dose, best timing of treatment onset, and optimal treatment duration for the use of lithium as a new treatment in fracture care.

METHODS

A design-of-experiments approach was used to assess the parameters of dose, timing of treatment onset, and treatment duration. Closed femoral shaft fractures were generated and analyzed with use of destructive torsional mechanical testing and microcomputed tomography-based image analysis. Eleven different outcome measures were quantified, with maximum yield torque as the primary study outcome, to assess the quality of long-bone fracture-healing.

RESULTS

Fracture-healing was maximized with a lithium treatment combination of a low dose (twenty milligrams per kilogram of body weight per day), later onset of lithium treatment (seven days after fracture), and longer treatment duration (two weeks), with maximum yield torque displaying a 46% increase compared with nontreated and sham-treated controls (481.1 ± 104.0 N-mm compared with 329.9 ± 135.8 N-mm; p = 0.04). Design-of-experiments analysis determined the timing of treatment onset to be the most influential parameter for improving fracture-healing, with femora treated at a later onset (seven days after fracture) showing a significant (21%) increase in maximum yield torque compared with those treated at an earlier onset (three days after fracture) (p = 0.01).

CONCLUSIONS

A later onset of lithium administration significantly improved femoral fracture-healing. Trends indicated that a lower dose and longer treatment duration also had a positive effect on fracture repair.

CLINICAL RELEVANCE

Orally administered low-dose lithium therapy with a large postfracture administration window has the potential to yield a safe, reliable, and cost-effective treatment to enhance bone-healing and restore earlier function and mobility pending appropriate large-animal proof-of-concept models, safety data, and U.S. Food and Drug Administration clinical trials approval.

Straight versus S-shaped sternotomy: a histologic study in the sheep model

Introduction

Straight sternotomy is the most common access for open heart surgery. Techniques have been proposed for maximizing sternal stability in high-risk patients. This trend implies a growing need for newer surgical techniques. The aim of this experimental study in the sheep model is to evaluate median vs. S shaped sternotomy the feasibility of using a special device to accelerate the sternal instability and bone healing.

Materials and methods

We enrolled 31 sheep, weighing 18–30 kg. For all animals a midline skin incision was made. In group I (n = 16 animals), straight median sternotomy and in group II (n = 15 animals), S-shaped incision was marked on the periosteum of the sternum by new created device for standard S-shaped sternotomy. Sternum biopsies were performed on second surgery month for all survived animals from the sternum and the surrounding soft tissue.

Results

No early superficial wound complications were observed. Overall mortality in the initial approach group was 19.3% (6 sheep). In group I; 3 sheep had died on first surgery day, the reason may be hemorrhage and in group II; 3 sheep developed intractable VF during surgery procedure or immediately afterwards so died. There were statistically significant differences in the scores of bone healing between group 1 and group 2 (4.2 vs.7.3, ANOVA, p < 0.001).

Discussion

Our work is based on the use of a standard S-shaped sternotomy procedure on sheep sternum. In our experience with the sternal healing in the sheep model, the process of new bone formation was accelerated with S- shaped cut than straight sternotomy procedure.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-014-0173-x) contains supplementary material, which is available to authorized users.

Levofloxacin increases the effect of serum deprivation on anoikis of rat nucleus pulposus cells via Bax/Bcl-2/caspase-3 pathway

Levofloxacin, a fluoroquinolone, is a widely-used and effective antibiotic. However, various adverse side effects are associated with levofloxacin. The purpose of this study was to further explore the effects of levofloxacin on rat nucleus pulposus cells (NPCs). Inverted phase-contrast microscopy, flow cytometry and caspase-3 activity assays were used and revealed that serum deprivation induced apoptosis, which was markedly increased by levofloxacin in a dose-dependent manner. Simultaneously, levofloxacin decreased cell binding to type II collagen (COL2). Thus, levofloxacin-induced apoptosis exhibits characteristics of anoikis, the process by which cell death is triggered by separation from the extracellular matrix, which contains COL2. Furthermore, real-time quantitative RT-PCR was used to further confirm that levofloxacin downregulates COL2 expression in a dose-dependent manner. At last, western blot was used to find that levofloxacin increased the ratio of Bax/Bcl-2 and active caspase-3 in a dose-dependent manner. Levofloxacin therefore increases the effects of serum deprivation on anoikis by downregulating COL2 in rat NPCs in vitro via Bax/Bcl-2/caspase-3 pathway. This research provides a novel insight into the mechanisms of levofloxacin-induced toxicity and may potentially lead to a better understanding of the clinical effects of levofloxacin, especially in terms of intervertebral disc degeneration.

Fluoroquinolone use in a child associated with development of osteochondritis dissecans

Several aetiological theories have been proposed for the development of osteochondritis dissecans. Cartilage toxicity after fluoroquinolone use has been well documented in vitro. We present a case report of a 10-year-old child who underwent a prolonged 18-month course of ciprofloxacin therapy for chronic urinary tract infections. This patient later developed an osteochondritis dissecans lesion of the medial femoral condyle. We hypothesise that the fluoroquinolone therapy disrupted normal endochondral ossification, resulting in development of osteochondritis dissecans. The aetiology of osteochondritis dissecans is still unclear, and this case describes an association between fluoroquinolone use and osteochondritis dissecans development.

Current Practice in the Management of Open Fractures Among Orthopaedic Trauma Surgeons. Part A: Initial Management. A Survey of Orthopaedic Trauma Surgeons

OBJECTIVES

Open fractures are one of the injuries with the highest rate of infection that orthopaedic trauma surgeons treat. The main purpose of this survey was to determine current practice and practice variation among Orthopaedic Trauma Association (OTA) members and make treatment recommendations based on previously published resources.

DESIGN

Survey.

SETTING

Web-based survey.

PARTICIPANTS

Three hundred seventy-nine orthopaedic trauma surgeons.

METHODS

A 15-item questionnaire-based study titled "OTA Open Fracture Survey" was constructed. The survey was delivered to all OTA membership categories. Different components of the data charts were used to analyze numerous aspects of open fracture management, focusing on parameters of initial and definitive treatment.

RESULTS

Eighty-six percent of participants responded that a period of time of less than 1 hour is the optimal time to antibiotic administration after identification of open fracture. Despite concerns with nephrotoxicity, 24.0%-76.3% of respondents reported the use of aminoglycosides in management of open fractures. A little over half of survey respondents continue antibiotics until next debridement in wounds that were not definitively closed after initial debridement and stabilization.

CONCLUSIONS

Rapid administration of antibiotics in open fracture management is important. Aminoglycoside use is still prevalent despite evidence questioning efficacy and toxicity concerns. Time to debridement of open fractures is controversial among OTA members. Antibiotic administration is commonly continued >48 hours despite concerns raised by Surgical Infection Society and The Eastern Association of the Surgery of Trauma. Regarding study logistics, survey participation reminders should be used when conducting this type of study as it can increase data accrual by 50%.

LEVEL OF EVIDENCE

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

Intrawound application of vancomycin reduces wound infection after open release of post-traumatic stiff elbows: a retrospective comparative study

BACKGROUND

With the improvements in wound healing through the use of intravenous prophylactic antibiotics and technical refinements, postoperative elbow infections have become less common but still occur in certain elective elbow surgeries. The objective of this study was to evaluate the safety and efficacy of prophylactic application of vancomycin into the operative site to reduce the incidence of infection after the open release of post-traumatic stiff elbows.

METHODS

A retrospective review of 272 such patients during a 4-year period was performed. In the control group (93 patients), simple prophylaxis with standard intravenous antibiotics was performed; in the vancomycin group (179 patients), vancomycin powder was applied directly into the wound before closure along with standard intravenous prophylaxis.

RESULTS

After a follow-up of at least 6 months, the control group was found to have 6 infections (6.45%; confidence interval: 2.40%-13.52%) compared with none (0%; confidence interval: 0-2%.04%) in the vancomycin group, which was a statistically significant difference (P = .0027). No adverse effects were documented from the direct use of the vancomycin powder.

CONCLUSIONS

The local application of vancomycin powder may be a promising means of preventing postoperative elbow infections after elbow release in patients with post-traumatic elbow stiffness.

Effects of caffeic acid phenethyl ester and melatonin on distraction osteogenesis: an experimental study

Aim

The aim of this experimental animal model study is to investigate the effects of caffeic acid phenethyl ester (CAPE) and melatonin on the maturation of newly-formed regenerated bone in distraction osteogenesis.

Methods

Unilateral femoral lengthening(extension) was applied to 39 adult male Wistar albino rats, which were randomly allocated to 3 groups of 13; control, melatonin and CAPE groups. Through a 7-day latent waiting period and 15 days of distraction, melatonin of 25 mg/kg and CAPE of 10 μmol/kg were administered to the respective groups. The animals were sacrificed on Day 82. Radiographic, histological and biomechanical evaluations were made and measurements were taken.

Results

At the end of 82 days, the distraction osteogenesis area was seen to be completely filled with new bone formation in all 3 groups both radiologically and histologically. Biomechanically, the maximum torsional fracture strength (Maximum Torque (N-m)) of the melatonin group was higher compared to that of the control group, although it was not statistically significant (p > 0.05). The maximum torsional momentum of the CAPE group was statistically significantly high (p < 0.05). The degree of rigidity (N-m/deg) of both the melatonin and CAPE groups was higher than that of the control group and the CAPE group was found to be statistically significantly higher than the melatonin group (p < 0.05).

Conclusion

Melatonin and CAPE increase the maturation of new bone in distraction osteogenesis. These effects are probably due to the reducing effect on bone resorption by inhibiting NF-κB and free oxygen radicals.

Prophylactic intrawound application of vancomycin powder in instrumented spinal fusion surgery

Objective

We evaluated the effect of intrawound application of vancomycin powder for infection prophylaxis in wounds caused by instrumented spinal surgery.

Methods

From July 2012 to December 2012, 74 instrumented spinal fusion procedures were performed by 1 neurosurgeon at a single institute. We divided the patients into 2 groups, depending on the use of local application of vancomycin powder: Group A (intrawound application of vancomycin powder with perioperative intravenous cefazolin) and Group B (perioperative intravenous cefazolin alone). A retrospective cohort comparative study was conducted between the 2 groups. The age, sex, comorbidities, smoking, surgical procedure, and surgical site infection (SSI) of consecutive patients were analyzed.

Results

Among the 74 patients, 34 patients were assigned to group A and 40 patients to group B. No wound infections were found in group A. However, in group B, 5 cases of SSI (12.5%) were found. A statistically significant reduction in SSI incidence was observed in group A (p<0.033). The 5 cases of SSI in group B consisted of 3 cases of deep wound infection and 2 cases of superficial wound infection. All SSIs were found in cases of posterior approach surgery and tended to be more frequent in older patients.

Conclusion

Adjunctive intrawound local application of vancomycin powder is a simple uncomplicated procedure and can result in a significant reduction of SSI in instrumented spinal fusions. Furthermore, culture of the drainage tip is very important for confirmation of deep wound infection.

Predictors of nonunion and reoperation in patients with fractures of the tibia: an observational study

Background

Tibial shaft fractures are the most common long bone fracture and are prone to complications such as nonunion requiring reoperations to promote fracture healing. We aimed to determine the fracture characteristics associated with tibial fracture nonunion, and their predictive value on the need for reoperation. We further aimed to evaluate the predictive value of a previously-developed prognostic index of three fracture characteristics on nonunion and reoperation rate.

Methods

We conducted an observational study and developed a risk factor list from previous literature and key informants in the field of orthopaedic surgery, as well as via a sample-to-redundancy strategy. We evaluated 22 potential risk factors for the development of tibial fracture nonunion in 200 tibial fractures. We also evaluated the predictive value of a previously-identified prognostic risk index on secondary intervention and/or reoperation rate. Two individuals independently extracted the data from 200 patient electronic medical records. An independent reviewer assessed the initial x-ray, the post-operative x-ray, and all available sequential x-rays. Regression and chi-square analysis was used to evaluate potential associations.

Results

In our cohort of patients, 37 (18.5%) had a nonunion and 27 (13.5%) underwent a reoperation. Patients with a nonunion were 97 times (95% CI 25.8-366.5) more likely to have a reoperation. Multivariable logistic regression revealed that fractures with less than 25% cortical continuity were predictive of nonunion (odds ratio = 4.72; p = 0.02). Such fractures also accounted for all of the reoperations identified in our sample. Furthermore, our data provided preliminary validation of a previous risk index predictive of reoperation that includes the presence of a fracture gap post-fixation, open fracture, and transverse fracture type as variables, with an aggregate of fracture gap and an open fracture yielding patients with the highest risk of developing a nonunion.

Conclusions

We identified a significant association between degree of cortical continuity and the development of a nonunion and risk for reoperation in tibial shaft fractures. In addition, our study supports the predictive value of a previous prognostic index, which inform discussion of prognosis following operative management of tibial fractures.

Autologous rabbit adipose tissue-derived mesenchymal stromal cells for the treatment of bone injuries with distraction osteogenesis

BACKGROUND AIMS

Adipose tissue-derived mesenchymal stromal cells (MSCs) have a higher capacity for proliferation and differentiation compared with other cell lineages. Although distraction osteogenesis is the most important therapy for treating bone defects, this treatment is restricted in many situations. The aim of this study was to examine the therapeutic potential of adipose tissue-derived MSCs and osteoblasts differentiated from adipose tissue-derived MSCs in the treatment of bone defects.

METHODS

Bone defects were produced in the tibias of New Zealand rabbits that had previously undergone adipose tissue extraction. Tibial osteotomy was performed, and a distractor was placed on the right leg of the rabbits. The rabbits were placed in control (group I), stem cell (group II) and osteoblast-differentiated stem cell (group III) treatment groups. The rabbits were sacrificed, and the defect area was evaluated by radiologic, biomechanical and histopathologic tests to examine the therapeutic effects of adipose tissue-derived MSCs.

RESULTS

Radiologic analyses revealed that callus density and the ossification rate increased in group III compared with group I and group II. In biomechanical tests, the highest ossification rate was observed in group III. Histopathologic studies showed that the quality of newly formed bone and the number of cells active in bone formation were significantly higher in group III rabbits compared with group I and group II rabbits.

CONCLUSIONS

These data reveal that osteoblasts differentiated from adipose tissue-derived MSCs shorten the consolidation period of distraction osteogenesis. Stem cells could be used as an effective treatment for bone defects.

Vitamin e and the healing of bone fracture: the current state of evidence

Background. The effect of vitamin E on health-related conditions has been extensively researched, with varied results. However, to date, there was no published review of the effect of vitamin E on bone fracture healing. Purpose. This paper systematically audited past studies of the effect of vitamin E on bone fracture healing. Methods. Related articles were identified from Medline, CINAHL, and Scopus databases. Screenings were performed based on the criteria that the study must be an original study that investigated the independent effect of vitamin E on bone fracture healing. Data were extracted using standardised forms, followed by evaluation of quality of reporting using ARRIVE Guidelines, plus recalculation procedure for the effect size and statistical power of the results. Results. Six animal studies fulfilled the selection criteria. The study methods were heterogeneous with mediocre reporting quality and focused on the antioxidant-related mechanism of vitamin E. The metasynthesis showed α-tocopherol may have a significant effect on bone formation during the normal bone remodeling phase of secondary bone healing. Conclusion. In general, the effect of vitamin E on bone fracture healing remained inconclusive due to the small number of heterogeneous and mediocre studies included in this paper.

Prognostic factors for predicting outcomes after intramedullary nailing of the tibia

BACKGROUND

Prediction of negative postoperative outcomes after long-bone fracture treatment may help to optimize patient care. We recently completed the Study to Prospectively Evaluate Reamed Intramedullary Nails in Patients with Tibial Fractures (SPRINT), a large, multicenter trial of reamed and unreamed intramedullary nailing of tibial shaft fractures in 1226 patients. Using the SPRINT data, we conducted an investigation of baseline and surgical factors to determine any associations with an increased risk of adverse events within one year of intramedullary nailing.

METHODS

Using multivariable logistic regression analysis, we investigated fifteen baseline and surgical factors for any associations with an increased risk of negative outcomes.

RESULTS

There was an increased risk of negative events in patients with a high-energy mechanism of injury (odds ratio [OR] = 1.57; 95% confidence interval [CI], 1.05 to 2.35), a stainless steel compared with a titanium nail (OR = 1.52; 95% CI, 1.10 to 2.13), a fracture gap (OR = 2.40; 95% CI, 1.47 to 3.94), and full weight-bearing status after surgery (OR = 1.63; 95% CI, 1.00 to 2.64). There was no increased risk with the use of nonsteroidal anti-inflammatory agents, late or early time to surgery, or smoking status. Open fractures had a higher risk of events among patients treated with reamed nailing (OR = 3.26; 95% CI, 2.01 to 5.28) but not in patients treated with unreamed nailing (OR = 1.50; 95% CI, 0.92 to 2.47). Patients with open fractures who had wound management either without any additional procedures or with delayed primary closure had a decreased risk of events compared with patients who required subsequent, more complex reconstruction (OR = 0.18 [95% CI, 0.09 to 0.35] and 0.29 [95% CI, 0.14 to 0.62], respectively).

CONCLUSIONS

We identified several baseline fracture and surgical characteristics that may increase the risk of adverse events in patients with tibial shaft fractures. Surgeons should consider the predictors identified in our analysis to inform patients treated for tibial shaft fractures.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.