Eradication of Staphylococcus aureus in Implant-Associated Osteomyelitis by an Injectable in situ-Forming Depot Antibiotics Delivery System.

BACKGROUND: Bone infections from Staphylococcus aureus are notoriously difficult to treat and have high recurrence rates. Local antibiotic delivery systems hold the potential to achieve high in situ antibiotic concentrations, which are otherwise challenging to achieve via systemic administration. Existing solutions have been shown to confer suboptimal drug release and distribution. Here we present and evaluate an injectable in situ-forming depot system termed CarboCell. The CarboCell technology provides sustained and tuneable release of local high-dose antibiotics. METHODS: CarboCell formulations of levofloxacin or clindamycin with or without antimicrobial adjuvants cis-2-decenoic acid or cis-11-methyl-2-dodecenoic acid were tested in experimental rodent and porcine implant-associated osteomyelitis models. In the porcine models, debridement and treatment with CarboCell-formulated antibiotics was carried out without systemic antibiotic administration. The bacterial burden was determined by quantitative bacteriology. RESULTS: CarboCell formulations eliminated S. aureus in infected implant rat models. In the translational implant-associated pig model, surgical debridement, and injection of clindamycin-releasing CarboCell formulations resulted in pathogen-free bone tissues and implants in 9/12, and full eradication in 5/12 pigs. CONCLUSIONS: Sustained release of antimicrobial agents mediated by the CarboCell technology demonstrated promising therapeutic efficacy in challenging translational models and may be beneficial in combination with the current standard of care.

Intraoperative tissue sampling for histology in chronic osteomyelitis shows high neutrophil infiltration centrally and low remains in debrided presumed infection-free regions.

INTRODUCTION: Histology of debrided bone tissue is a confirmatory diagnostic criterion for fracture related infection (FRI) and prosthetic joint infection (PJI). The aim of the present study was to describe the histopathology of the first and last debrided bone tissue in chronic osteomyelitis (CO) according to the international diagnostic guidelines for FRI and PJI. METHODS: 15 patients with CO were allocated to surgical treatment using a one-stage protocol including extensive debridement. Suspected infected bone tissue eradicated early in the debridement procedure was collected as a clearly infected sample (S1). Likewise, the last eradicated bone tissue was collected as a suspected non-infected sample (S2). The samples were processed for histology. HE-stained sections were patho-morphologically examinated. Immunohistochemistry with MAC-387 antibodies towards calprotectin was used for estimation of neutrophil granulocyte (NP) score (0, 1, 2 or 3). RESULTS: S1 samples showed a mean NP score of 2.6 (3 is confirmatory for infection). Following debridement, the NP score was significantly (p = 0.005) reduced to a mean NP score of 1.6. The S1 samples showed a mix of fibrovascular tissue, dense fibrosis, viable bone, bone necrosis and bone debris. S2 samples contained mostly viable bone tissue, however, often small fragments of necrotic bone or bone debris were present. CONCLUSION: The inflammatory response of CO still exists after debridement, although the response fades from the center. Therefore, sampling of debrided bone tissue for histology must be performed initially during surgery, otherwise there is a risk for underestimation of NP infiltration. The present results might also be highly relevant for FRI and PJI.

Bacterial invasion of the submicron osteocyte lacuna-canaliculi network (OLCN): a part of osteomyelitis disease biology.

Two chronic osteomyelitis patients, a diabetic foot osteomyelitis patient and a fracture-related infection patient, all with staphylococci-positive microbiology, were examined to confirm the clinical relevance of bacterial invasion of the submicron osteocyte lacuna-canaliculi network (OLCN) in bone tissue. Based on immunohistochemistry and light microscopy both Staphylococcus aureus and Staphylococcus epidermidis were identified within the OLCN of all four patients. The findings consolidate that bacterial OLCN invasion is a clinically relevant part of osteomyelitis disease biology, which from experimental porcine infections, seems to be time depending. The microscopy pictures of the four patients significantly add to visualize the phenomenon of bacterial OLCN invasion.

Treatment of Diabetic Foot Ulcers With Inforatio Technique to Promote Wound Healing: A Feasibility Trial.

Chronic foot ulcers have extensive consequences for diabetic patients' quality of life and increase risks of amputation and death. The aim of this trial was to assess the feasibility of conducting a larger clinical trial to evaluate the clinical effect of inforatio technique on healing of diabetic foot ulcers (DFUs). Inforatio technique is a novel minimal invasive procedure where small cuts are made on wound beds with punch biopsy tools. This study was a feasibility trial conducted at an outpatient wound care clinic at Zealand University Hospital. Twelve patients with DFUs were included. During a 90-day follow-up, participants visited the clinic 5 times and received inforatio technique twice. Feasibility was assessed with regard to recruitment, acceptability, burden, benefits, protocol adherence, and adverse events. The recruitment rate was 1 patient per eighth day (95% confidence interval [CI] = [4th-13th]), and the retention rate was 100% (95% CI = [74-100]). During follow-up, healing was observed for 4 ulcers (33%, 95% CI = [10-65]) with a mean time for healing of 59 days (range, 22-89) (95% CI = [5-113]). Five ulcers had a reduction of wound area and 3 ulcers had an increase in area from baseline to 90-day follow-up. No temporal relationship was found between inforatio application and wound area increase. There were no patient-reported harmful effects and no adverse events with probable relation to inforatio technique. Patient acceptability and participant adherence were promising. Thus, a larger clinical trial for evaluating the clinical effect of inforatio technique is considered feasible to conduct.

[Fracture-related infections].

Fracture-related infections (FRI) is a challenging complication with a high risk of devastation outcomes for the patients. Diagnosing FRI is often difficult, and treatment frequently requires the effort of a multidisciplinary team. Recently, an international consensus group of experts from various scientific and medical organisations has published standardised guidelines of diagnosis and treatment. This review provides a summary of the latest studies and the general principles with respect to diagnosis, treatment and aftercare of patients with FRI.

Inforatio technique to promote wound healing of diabetic foot ulcers: study protocol for a parallel-group, evaluator-blinded, randomised clinical trial.

INTRODUCTION: Diabetic foot ulcers (DFUs) are associated with extensive consequences for the affected patients and treatment of these hard-to-heal ulcers is known for being challenging. New treatment methods to supplement the current standard care may improve the prognosis for these patients.A preceding feasibility trial with promising results, facilitated this trial that aims to study the effect of a novel simple treatment, called inforatio technique, which may promote healing of DFUs. The inforatio technique is a minimally invasive procedure where small cuts are made on wound beds with punch biopsy tools. METHODS AND ANALYSIS: This multicentre randomised clinical trial will be conducted at outpatient clinics at Zealand University Hospital, Herlev University Hospital, Slagelse Hospital and Nykoebing Falster Hospital. 100 participants will be included and randomised in a 1:1 ratio to either a control group that receives usual care or an intervention group that receives both usual care and the inforatio technique.The primary outcome is complete healing evaluated on digital images by blinded observers. It is not possible to blind participants or the outpatient clinic staff because the inforatio technique is visible in wound beds after application. Change in EQ-5D-5L (EuroQoL-5 Dimension- 5 Level) Visual Analogue Scale Score and Wound-QoL Global Score from baseline to end of follow-up are secondary outcomes. ETHICS AND DISSEMINATION: Ethics approval has been granted by the Danish National Committee on Health Research Ethics on 15 December 2021 (approval ID: SJ-904). Trial results are planned to be published in a high-impact peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT05189470.

Assessment of diabetic foot ulcers based on pictorial material: an interobserver study.

OBJECTIVE: The frequent change in clinicians, and the emerging use of photographic documentation in wound management, could require a more diverse treatment of patients due to poor interobserver agreement. The aim of this study was to assess the interobserver agreement of a commonly used classification system for diabetic foot ulcers (DFUs), the Meggitt-Wagner classification, and to compare the agreement on classification with the agreement in treatment recommendations. METHOD: An interobserver study was conducted based on a questionnaire linked to 30 photographs of DFUs. Different groups of observers were tested to investigate whether there was a difference between professions or level of education: experienced orthopaedic wound care doctors (n=7); nurses specialised in wound care (n=8) and untrained nurses assigned to a diabetic wound care training course (n=23). Krippendorff's alpha was used to calculate interobserver agreement, and an agreement of >0.67 was defined as substantial. RESULTS: The Krippendorff's alpha value for interobserver agreement on the Meggitt-Wagner classification was 0.52 for the doctors group, 0.67 for the specialised nurses and 0.61 for the untrained nurses. The corresponding values regarding agreement on recommendation of surgical revision of the wound were 0.35, 0.22 and 0.15, respectively. The choice of dressing type or antibiotic treatment had even lower interobserver agreement. CONCLUSIONS: The interobserver agreement on the Meggitt-Wagner classification was substantial in the specialised nurse group, but the evaluation and treatment of DFUs should not be exclusively based on pictorial materials.

Pathological and microbiological impact of a gentamicin-loaded biocomposite following limited or extensive debridement in a porcine model of osteomyelitis.

AIMS: CERAMENT|G is an absorbable gentamicin-loaded biocomposite used as an on-site vehicle of antimicrobials for the treatment of chronic osteomyelitis. The purpose of the present study was to investigate the sole effect of CERAMENT|G, i.e. without additional systemic antimicrobial therapy, in relation to a limited or extensive debridement of osteomyelitis lesions in a porcine model. METHODS: Osteomyelitis was induced in nine pigs by inoculation of 104 colony-forming units (CFUs) of Staphylococcus aureus into a drill hole in the right tibia. After one week, the pigs were allocated into three groups. Group A (n = 3) received no treatment during the study period (19 days). Groups B (n = 3) and C (n = 3) received limited or extensive debridement seven days postinoculation, respectively, followed by injection of CERAMENT|G into the bone voids. The pigs were euthanized ten (Group C) and 12 (Group B) days after the intervention. RESULTS: All animals presented confirmatory signs of bone infection post-mortem. The estimated amount of inflammation was substantially greater in Groups A and B compared to Group C. In both Groups B and C, peptide nucleic acid fluorescence in situ hybridization (PNA FISH) of CERAMENT|G and surrounding bone tissue revealed bacteria embedded in an opaque matrix, i.e. within biofilm. In addition, in Group C, the maximal measured post-mortem gentamicin concentrations in CERAMENT|G and surrounding bone tissue samples were 16.6 µg/ml and 6.2 µg/ml, respectively. CONCLUSION: The present study demonstrates that CERAMENT|G cannot be used as a standalone alternative to extensive debridement or be used without the addition of systemic antimicrobials.Cite this article: Bone Joint Res 2020;9(7):394-401.

Nonunion - consensus from the 4th annual meeting of the Danish Orthopaedic Trauma Society.

Nonunions are a relevant economic burden affecting about 1.9% of all fractures. Rather than specifying a certain time frame, a nonunion is better defined as a fracture that will not heal without further intervention.Successful fracture healing depends on local biology, biomechanics and a variety of systemic factors. All components can principally be decisive and determine the classification of atrophic, oligotrophic or hypertrophic nonunions. Treatment prioritizes mechanics before biology.The degree of motion between fracture parts is the key for healing and is described by strain theory. If the change of length at a given load is > 10%, fibrous tissue and not bone is formed. Therefore, simple fractures require absolute and complex fractures relative stability.The main characteristics of a nonunion are pain while weight bearing, and persistent fracture lines on X-ray.Treatment concepts such as 'mechanobiology' or the 'diamond concept' determine the applied osteosynthesis considering soft tissue, local biology and stability. Fine wire circular external fixation is considered the only form of true biologic fixation due to its ability to eliminate parasitic motions while maintaining load-dependent axial stiffness. Nailing provides intramedullary stability and biology via reaming. Plates are successful when complex fractures turn into simple nonunions demanding absolute stability. Despite available alternatives, autograft is the gold standard for providing osteoinductive and osteoconductive stimuli.The infected nonunion remains a challenge. Bacteria, especially staphylococcus species, have developed mechanisms to survive such as biofilm formation, inactive forms and internalization. Therefore, radical debridement and specific antibiotics are necessary prior to reconstruction. Cite this article: EFORT Open Rev 2020;5:46-57. DOI: 10.1302/2058-5241.5.190037.

The host response to bacterial bone infection involves a local upregulation of several acute phase proteins.

Bone infections often become chronic and can be difficult to diagnose. In the present study, the osseous gene expression of several acute phase proteins (APPs) during osteomyelitis was investigated in a porcine model of implant associated osteomyelitis (IAO) (sampled 5, 10 and 15 days after infection) and in slaughter pigs with spontaneous hematogenous osteomyelitis, and compared to gene expression in liver tissue. Furthermore, immunohistochemical (IHC) staining of the APP complement component C3 (C3) was performed on the porcine osteomyelitis lesions together with material from human patients with chronic osteomyelitis. In the porcine bone samples a local upregulation of the expression of several APP genes, including serum amyloid A (SAA) and C3, was observed during infection. In the liver, only C-reactive protein (CRP) and Inter-Alpha-Trypsin Inhibitor Heavy Chain 4 were significantly upregulated. Serum concentrations of CRP, SAA and haptoglobin were only upregulated at day 5 in infected animals of the IAO model. This indicates a limited systemic response to osteomyelitis. Similar numbers of positive IHC stained C3 leukocytes were found in human and porcine bone samples with chronic osteomyelitis, indicating a high transcriptional value of porcine models of osteomyelitis. The local upregulation of APPs could potentially be used for diagnosing osteomyelitis.

Wound complications after ankle surgery. Does compression treatment work? A randomized, controlled trial.

PURPOSE: Infection rates following ankle fractures are as high as 19% in selected material and is the most common complication following this type of surgery, with potential catastrophic consequences. The purpose of this study was to test a regime of intermittent pneumatic compression, a compression bandage and a compression stocking and its effect on the rate of wound complications. The hypothesis was that compression could lower the infection rate from 20 to 5%. METHODS: We performed a randomized, controlled, non-blinded trial, including 153 adult patients with unstable ankle fractures. Patients were randomized to either compression (N = 82) or elevation (N = 71). Patients with open fracture, DVT, pulmonary embolism, dementia, no pedal pulse, or no Danish address were excluded. Primary endpoint was infection. Secondary endpoints were necrosis and wound dehiscence. RESULTS: After 2 weeks, 1.4% (0.0;7.6) in the compression group had infection compared to 4.6% (1.0;12.9) in the control group, p = 0.35. The rate of necrosis after 2 weeks was 7.0% (95% CI 2.3;15.7) in the compression group compared with 26.2% (95% CI 16.0;38.5) in the elevation group, p = 0.004. No difference was shown regarding wound dehiscence. CONCLUSION: Based on this study, we cannot conclude if compression therapy prevents infection or not. This is mainly due to under-powering of the study. The effect on necrosis was in favor of compression, but the trial was not powered to show a difference regarding this endpoints and the result is thus hypothesis generating. Further research is needed before a thorough recommendation on the use of compression treatment that can be made.

[Early diagnosis and treatment of Boerhaave's syndrome is pivotal for the prognosis]. / Tidlig diagnostik og behandling af Boerhaaves syndrom er afgørende for prognosen.

Hydropneumothorax following oesophageal rupture is very rare and often lethal. We report case of a 78-year-old man with known Barret's oesophagus with increasing shortness of breath and right chest pain followed by increasing emesis. Further investigations showed a right side hydropneumothorax and pleural effusion. Thorax and abdominal CT showed middle oesophageal perforation and pneumomediastinum. Oesophageal perforation can lead to pneumothorax and pleural fluid. Early diagnosis is pivotal to reduce mortality.