Osteomyelitis in the diabetic foot

Predictors of limb saving in diabetic foot ulcer

Objectives

This study was aimed to determine the various factors which could serve as predictor of saving of lower limb from amputation in patients with diabetic foot ulcer (DFU).

Method

This three-year retrospective study was conducted in the Diabetes and Endocrinology Unit of Hayatabad Medical complex Peshawar, Pakistan. Demographic, clinical, laboratory and radiological information of the diabetic patients with DFU admitted between January 2020 to December 2022 was retrieved from the hospital files. Information regarding initial and final decision regarding amputation and the outcome of the ulcer was also recorded.

Results

A total of 502 patients of diabetes mellitus (DM) with DFU were included in the study, of whom there were 279 (55.6%) males and 223 (44.4%) females. The mean age of the study population, mean duration of DM and mean HbA1c were 55.2 ± 9.8 years, 13.7 ± 6.7 years and 11.2 ± 2.4 %, respectively. Patients who had an amputation of their lower limbs had an increased age (p= 0.034), raised total leucocyte count (TLC) (p= <0.001), higher HbA1c (p= 0.025), had osteomyelitis (p= <0.001), and had a higher-grade ulcer (p= <0.001). On binary logistic regression analysis, ulcer grade (OR=7.4, p= <0.001), osteomyelitis (OR=11.8, p= <0.001), and initial decision of no amputation at the time of admission (OR=33.6, p=<0.001) were independently associated with the lower limb salvage.

Conclusion

DFU which were of grade I to II, had no evidence of osteomyelitis and for which an initial decision was of no amputation were more likely to be salvaged.

Trajectories of Diabetes-Related Sequelae for Identifying Transition Probabilities, and Optimal Timepoints for Prevention of Ulceration, Infection, and Amputation

To reduce diabetes-related complications and to avoid futile procedures, foot and ankle surgeons need to understand the relative timings of catastrophic events, their incidence, and probabilities of transitions between disease states in diabetes in different patient populations. For this study, we tracked medical events (including an initial diagnosis of diabetes, ulcer, wound care, osteomyelitis, amputation, and reamputation, in order of severity) and the time between each such event in patients with diabetes, stratifying by sex, race, and ethnicity. We found that the longest average duration between the different lower extremity states was a diagnosis of diabetes to the occurrence of ulcer at 1137 days (38 months). The average durations of amputation to reamputation, osteomyelitis, wound care, and ulcer were 18, 49, 23, and 18 days, respectively. The length of each disease transition for females was greater, while those of the Hispanic population were shorter than in the total cohort. This knowledge may permit surgeons to time and tailor treatments to their patients, and help patients to address, delay, or avoid complications.

Concomitants of Diabetic Foot Ulcer - A Review

BACKGROUND

Diabetes mellitus leading to foot ulcer is a serious complication, and it is considered a global epidemic. Neuropathyand high blood glucose levels are the primary causes of foot ulcers. Fifteen percent of people with diabetes develop foot ulcers, and these foot disorders are the main cause of lower extremity amputation among such patients.

INTRODUCTION

Complications of diabetic foot, affecting the lower extremities are common and quite complex and life-threatening. This review focuses on the life-threatening factors associated with diabetic foot ulcers and also the diagnosing and preventive measures. Neuropathy assessment and the range of foot ulcers were accurately examined.

CONCLUSION

Novel therapies focusing on the vascularity of the lower limbs, infection control, and ischemic control are being developed to mainly treat nonhealing ulcers.

Investigation and management of diabetic foot osteomyelitis: An update for the foot and ankle orthopaedic surgeon

Diabetic foot osteomyelitis (DFO) poses a significant challenge in the management of diabetic patients, often leading to severe complications and increased morbidity. Effective management of DFO requires a multidisciplinary approach, involving endocrinologists, infectious disease specialists, vascular surgeons, orthopaedic surgeons, and wound care experts. Early diagnosis is paramount, facilitated by advanced imaging techniques such as magnetic resonance imaging (MRI) and bone scintigraphy. Once diagnosed, the treatment strategy hinges on a combination of medical and surgical interventions. Antibiotic therapy, guided by culture results, plays a central role in managing DFO. Tailored regimens targeting the specific pathogens involved are administered, often for prolonged durations. Surgical intervention becomes necessary when conservative measures fall short. Surgical approaches range from minimally invasive procedures, like percutaneous drainage, to more extensive interventions like debridement and bone resection. Prevention of DFO recurrence is equally vital, emphasising glycemic control, meticulous foot care, patient education, monitoring of at-risk signs, revascularization and early intervention when indicated. The management of diabetic foot osteomyelitis mandates a comprehensive strategy that addresses both the infectious and surgical aspects of the condition. A collaborative, interdisciplinary approach ensures timely diagnosis, tailored treatment, and holistic care. Further research into novel therapeutic modalities and long-term outcomes remains essential in refining the management of this complex and debilitating complication of diabetes.

Basic haematological tests as inflammatory performance markers of patients treated either by conservative surgery or minor amputation for infected diabetic foot ulcers

Basic inflammatory markers have been extensively studied to differentiate between non-infected and infected diabetic foot ulcers (DFUs). Very rarely, basic haematological tests such as white cell count (WCC) and platelet counts were used as performance markers for DFU infection severity. The aim is to investigate these biomarkers in patients with DFU treated exclusively with surgery. In this retrospective comparative study, we included 154 procedures comparing a conservative surgery group (n = 66 for infected DFU) and a minor amputation group (n = 88 for infected DFU with osteomyelitis). Outcomes were set as the preoperative values of: WCC, neutrophils (N), lymphocytes (L), Monocytes (M), Platelets (P), red cell distribution width (RDW) and the ratios N/L, L/M and P/L. Area under curve (AUC) of the receiver operating characteristic (ROC) was calculated based on the diagnosis of minor amputation as a positive result. Cutoff point values with the highest sensitivity and specificity were obtained for each outcome. The highest AUC values were for WCC (0.68), neutrophils (0.68), platelets (0.7) and P/L ratio (0.69) with corresponding cut-off values of 10,650/mm3 , 76%, 234,000/mcL and 265, respectively. The highest sensitivity was for the platelet count (81.5%) while the highest specificity was for L/M (89%) and P/L ratios (87%). Postoperative values showed similar results. Simple routine blood tests could serve as inflammatory performance markers to help predict the severity of infection in patients treated surgically for infected DFU.

Adiponectin as a therapeutic target for diabetic foot ulcer

The global burden of diabetic foot ulcers (DFUs) is a significant public health concern, affecting millions of people worldwide. These wounds cause considerable suffering and have a high economic cost. Therefore, there is a need for effective strategies to prevent and treat DFUs. One promising therapeutic approach is the use of adiponectin, a hormone primarily produced and secreted by adipose tissue. Adiponectin has demonstrated anti-inflammatory and anti-atherogenic properties, and researchers have suggested its potential therapeutic applications in the treatment of DFUs. Studies have indicated that adiponectin can inhibit the production of pro-inflammatory cytokines, increase the production of vascular endothelial growth factor, a key mediator of angiogenesis, and inhibit the activation of the intrinsic apoptotic pathway. Additionally, adiponectin has been found to possess antioxidant properties and impact glucose metabolism, the immune system, extracellular matrix remodeling, and nerve function. The objective of this review is to summarize the current state of research on the potential role of adiponectin in the treatment of DFUs and to identify areas where further research is needed in order to fully understand the effects of adiponectin on DFUs and to establish its safety and efficacy as a treatment for DFUs in the clinical setting. This will provide a deeper understanding of the underlying mechanisms of DFUs that can aid in the development of new and more effective treatment strategies.

Predictors of delayed wound healing after simultaneous endovascular treatment and minor forefoot amputation for chronic limb-threatening ischemia with wound infection

OBJECTIVES

To assess wound healing after simultaneous endovascular treatment (EVT) and minor forefoot amputation and identify the predictors of delayed wound healing in patients with chronic limb-threatening ischemia (CLTI) and bacterial infections of the wounds.

METHODS

In this single-center retrospective cohort study, we evaluated 79 consecutive limbs with tissue loss from 73 CLTI patients who underwent simultaneous EVT and minor forefoot amputation between November 2017 and May 2020. To estimate the rate of wound healing after the simultaneous procedure, we used the Kaplan-Meier method. To assess the association between baseline characteristics and delayed wound healing, we used the Cox proportional hazard model.

RESULTS

All patients who underwent the simultaneous procedure had ischemic wounds with bacterial infection. The rate of wound healing at 6 months reached 82%. The median time for wound healing was 76 days. According to multivariable analysis, Lisfranc/Chopart amputation (hazard ratio (HR) 2.46, 95% confidence interval (CI) 1.09-6.60), absence of above-the-knee (ATK) occlusive lesions (HR 1.89, 95% CI 1.04-3.45), and poor below-the-ankle (BTA) runoff (HR 1.77, 95% CI 1.01-3.11) were independent predictors of delayed wound healing.

CONCLUSION

Lisfranc/Chopart amputation, absence of ATK occlusive lesions, and poor BTA runoff were independent predictors of delayed wound healing after simultaneous EVT and minor forefoot amputation in patients with CLTI and bacterial infections of the wound.

Treatment of diabetic foot ulcers: review of the literature with regard to the TIME clinical decision support tool

OBJECTIVE

The aim of this clinically orientated paper is to offer an overview of diabetic foot ulcer (DFU) dressings generally, and more specifically, their use in the treatment of DFUs.

METHOD

The TIME clinical decision support tool (CDST) has been used as a clinical tool that can help clinicians bring together the different aspects of dressings for DFU treatment into a holistic approach to patient care.

RESULTS

DFUs are often difficult to heal, are painful and impact negatively on the individual's quality of life. Most DFU dressings are designed to support the healing of hard-to-heal wounds and represent one part of the management of DFUs. Apart from providing a moist environment, absorbing increased exudate, enhancing granulation and assisting in autolysis, the dressings need to be cost-effective. Wound dressing selection is based on clinical knowledge that ensures the dressing is most appropriate for the individual and the wound, taking into account the comorbidities that the individual may have.

CONCLUSION

This paper has highlighted how the use of the TIME CDST model can enhance clinical care and is a further tool clinicians should consider when developing and executing DFU treatment plans. Future research needs to focus on large multicentre studies using robust methodologies, given the current gaps in the evidence, to determine the effectiveness of dressing products for DFUs.

Microbiology of diabetic foot osteomyelitis - Is it geographically variable?

INTRODUCTION

Diabetic foot osteomyelitis (DFO) is a dreaded complication as both diagnosis and treatment of the condition is laborious. However, for proper decision on antibiotics in medical management of DFO, accurate determination of microbes is necessary to narrow the spectrum of coverage and to reduce adverse effects of long-term administration of antibiotics. With differing pattern of use of antimicrobials and their resistance pattern in different countries, it is empirical to determine the microbiological characteristics of bone cultures in DFO from a referral institute in South India.

MATERIALS AND METHODS

This study was a retrospective chart review of all cases of proven DFO who had consented for debridement and bone culture or those who underwent amputation. Both deep soft tissue (DST) and bone cultures were obtained for aerobic bacteria. Clinical characteristics and site(s) of DFO were recorded. Investigations for peripheral artery disease were performed if clinically indicated.

RESULTS

In all, 105 patients with DFO were reviewed. Mean age was 62 years and 70% were men. Of those who were screened, 57% had evidence of peripheral arterial disease by arterial doppler. 46% of bone culture samples were sterile. Gram- negative organisms were more common (58%). Following staphylococcus, pseudomonas was the second common isolate. Of total staphylococcal isolates 37% were MRSA and 33% of klebsiella isolates were ESBL producing. Concordance rate between DST and bone cultures was 66%. 90% were mono-bacterial isolates. The commonest site of involvement of DFO was terminal phalanges of toes rather than base of 1st metatarsal.

CONCLUSION

Widespread use of antibiotics, tropical climate and route of entry of organisms causing DFO differed in our cohort of patients. Further studies from different regions of world would shed light onto different pattern of microbes causing DFO.

High-strength biodegradable zinc alloy implants with antibacterial and osteogenic properties for the treatment of MRSA-induced rat osteomyelitis

Implant-related infections caused by drug-resistant bacteria remain a major challenge faced by orthopedic surgeons. Furthermore, ideal prevention and treatment methods are lacking in clinical practice. Here, based on the antibacterial and osteogenic properties of Zn alloys, Ag and Li were selected as alloying elements to prepare biodegradable Zn-Li-Ag ternary alloys. Li and Ag addition improved the mechanical properties of Zn-Li-Ag alloys. The Zn-0.8Li-0.5Ag alloy exhibited the highest ultimate tensile strength (>530 MPa). Zn-Li-Ag alloys showed strong bactericidal effects on methicillin-resistant Staphylococcus aureus (MRSA) in vitro. RNA sequencing revealed two MRSA-killing mechanisms exhibited by the Zn-0.8Li-0.5Ag alloy: cellular metabolism disturbance and induction of reactive oxygen species production. To verify that the therapeutic potential of the Zn-0.8Li-0.5Ag alloy is greater than that of Ti intramedullary nails, X-ray, micro-computed tomography, microbiological, and histological analyses were conducted in a rat femoral model of MRSA-induced osteomyelitis. Treatment with Zn-0.8Li-0.5Ag alloy implants resulted in remarkable infection control and favorable bone retention. The in vivo safety of this ternary alloy was confirmed by evaluating vital organ functions and pathological morphologies. We suggest that, with its good antibacterial and osteogenic properties, Zn-0.8Li-0.5Ag alloy can serve as an orthopedic implant material to prevent and treat orthopedic implant-related infections.

The efficacy of inflammatory markers in diagnosing infected diabetic foot ulcers and diabetic foot osteomyelitis: Systematic review and meta-analysis

Background

Diabetes foot ulcer (DFU) is a complication of diabetes mellitus. Accurate diagnosis of DFU severity through inflammatory markers will assist in reducing impact on quality of life. We aimed to ascertain the diagnostic test accuracy of commonly used inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), and white cell count (WCC) for the diagnosis and differentiation between DFU grades based on the International Working Group on the Diabetic Foot classification system.

Methods

This systematic review explored studies that investigated one or more of the above-listed index tests aiding in diagnosing infected DFU. This review was registered on PROSPERO database (ID = CRD42021255618) and searched 5 databases including an assessment of the references of included studies. Records were manually screened as per Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. A total of 16 studies were included which were assessed for quality using QUADAS-2 tool and meta-analysed using Meta-Disc v1.4.

Results

CRP had the greatest area under the curve (AUC) of 0.893 for diagnosing grade 2 DFU. This returned a pooled sensitivity and specificity of 77.4% (95% CI: 72% to 82%) and 84.3% (95% CI: 79% to 89%) respectively. In terms of diagnosing grade 3 DFU, procalcitonin had the highest AUC value of 0.844 when compared with other markers. The pooled sensitivity of PCT was calculated as 85.5% (95% CI: 79% to 90%) and specificity as 68.9% (95% CI: 63% to 75%).

Conclusion

CRP and PCT are the best markers for diagnosing grade 2 and grade 3 DFU respectively. Other markers are also valuable when used in conjunction with clinical judgement. The findings accentuate the necessity of further research to establish standardised cut-off values for these inflammatory markers in diagnosing diabetic foot ulcers.

Quorum sensing modulation and inhibition in biofilm forming foot ulcer pathogens by selected medicinal plants

The crisis of antibiotic resistance necessitates the search of phytochemicals as potential antibacterial, anti-quorum sensing and antibiofilm forming agents. For the present study, fifteen (15) selected medicinal plants were evaluated to inhibit the biological activities of multi-drug resistant (MDR) pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis) associated with diabetic foot ulcer. Antibacterial activities revealed noteworthy minimum inhibitory concentration (MIC) values ≤1 mg/mL for thirteen (13) out of the sixty (60) plant extracts screened. The potent extracts included Euclea natalensis ethyl acetate (0.25 mg/mL), Aloe ferox methanol (0.5 mg/ml) and Warburgia salutaris aqueous (0.5 mg/mL) extracts. Chemical profiling of the active extracts using gas chromatography-mass spectrometry (GC-MS) identified neophytadiene, guanosine, squalene, cis megastigma-5,8-diene-4-one and sorbitol as prevalent compounds among the active extracts. Anti-quorum sensing activities of E. natalensis (ethyl acetate), A. ferox (methanol) and W. salutaris (aqueous) extracts ranged from 4.81 - 58.34% with E. natalensis (ethyl-acetate) showing the highest activity. Molecular docking against CviR protein showed selected compounds having high docking scores with sorbitol showing the highest score of -7.04 kcal/mol. Warburgia salutaris aqueous extract exhibited the highest biofilm inhibition (73%) against E. coli. Euclea natalensis, Aloe ferox and Warburgia salutaris compounds act as antagonist of N-acyl homoserine lactone (AHL) signaling, thus may serve as candidates in antipathogenic and antibiofilm phytomedicine development for MDR foot ulcer bacterial pathogens.

Imaging with [99mTc]HMPAO - a novel perspective: investigation of [99mTc]HMPAO leg muscle uptake in metabolic diseases

BACKGROUND

Sensitive imaging modalities in the diagnosis of microcircular complications of the lower extremities induced by metabolic diseases are becoming a focus of interest.

PURPOSE

To investigate the [^99mTc]HMPAO uptake of the legs in type 2 diabetes mellitus (T2DM) and obesity, and to search for associations with clinical parameters and nerve conducting studies.

MATERIAL AND METHODS

A total of 57 patients with controlled T2DM and 46 obese participants without DM were enrolled in the study. [^99mTc]HMPAO SPECT/CT examinations were performed to evaluate the radiopharmaceutical accumulation of the legs. For the quantitative assessment of tracer uptake, standardized uptake value (SUV_peak) was measured in fixed spheric volumes of interest placed on both sural muscles on the attenuation-corrected images. Measurement of current perception threshold applying Neurometer (NM-01/CPT) was used to evaluate peripheral nerve dysfunction. Laboratory parameters assessing the glucose homeostasis of the study participants were also measured.

RESULTS

In the diabetic group, significantly lower leg SUV values were detected compared to the non-DM obese group (median: 0.517 vs. 0.607; P < 0.001). Body mass index (BMI) (P < 0.0001), age (P = 0.0283), HbA1c (P = 0.0068), and glucose level (P = 0.0044) proved to be significant predictors of muscle tracer uptake. Neurometer studies showed positive correlation with HbA1c levels in the T2DM group (P = 0.0002).

CONCLUSION

We assume that [^99mTc]HMPAO uptake of leg muscles is associated with microcirculation, so quantitative [^99mTc]HMPAO SPECT/CT might be a sensitive method for evaluating lower limb microvascular alterations. BMI, age, HbA1c, and glucose level may be significant predictors of peripheral vascular abnormalities triggered by metabolic disturbances.

Multidisciplinary Approach for the Management and Treatment of Diabetic Foot Infections with a Resorbable, Gentamicin-Loaded Bone Graft Substitute

Diabetic patients are at increased risk of developing foot ulcers which may cause bone infections associated with a high probability of both amputation and mortality. Therefore, prompt diagnosis and adequate treatment are of key importance. In our Diabetic Foot Unit, effective multidisciplinary treatment of osteomyelitis secondary to diabetes involves the application of a gentamicin-eluting calcium sulphate/hydroxyapatite bone graft substitute to fill residual bone voids after debridement. The data of all patients treated with the gentamicin-eluting calcium sulphate/hydroxyapatite bone graft substitute for diabetic foot infections with ulcer formation and osteomyelitis at metatarsals, calcaneus and hindfoot at our institute from July 2013 to September 2016 were retrospectively collected and evaluated. A total of 35 patients were included in this retrospective single-arm case series and were either continuously followed up for at least one year or until healing was confirmed. Nineteen lesions affected the distal row of tarsus/talus, ten the calcaneus and a further six were located at the metatarsals. While all of the metatarsal lesions had healed at 1-year follow-up, the healing rate in the hindfoot region was lower with 62.5% at the calcaneus and 72.2% at the distal tarsus and talus at 12 months, respectively. The overall cure rate for ulcerous bone infection was 81.3%. In two calcaneal lesions (25%) and two lesions of distal tarsus/talus (11.1%) amputation was considered clinically necessary. Promising results were achieved in the treatment of diabetic foot infections with soft tissue ulcers by a multidisciplinary approach involving extensive debridement followed by adequate dead space management with a resorbable gentamicin-eluting bone graft substitute.

Imaging tests for the detection of osteomyelitis: a systematic review

BACKGROUND

Osteomyelitis is an infection of the bone. Medical imaging tests, such as radiography, ultrasound, magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and positron emission tomography (PET), are often used to diagnose osteomyelitis.

OBJECTIVES

To systematically review the evidence on the diagnostic accuracy, inter-rater reliability and implementation of imaging tests to diagnose osteomyelitis.

DATA SOURCES

We conducted a systematic review of imaging tests to diagnose osteomyelitis. We searched MEDLINE and other databases from inception to July 2018.

REVIEW METHODS

Risk of bias was assessed with QUADAS-2 [quality assessment of diagnostic accuracy studies (version 2)]. Diagnostic accuracy was assessed using bivariate regression models. Imaging tests were compared. Subgroup analyses were performed based on the location and nature of the suspected osteomyelitis. Studies of children, inter-rater reliability and implementation outcomes were synthesised narratively.

RESULTS

Eighty-one studies were included (diagnostic accuracy: 77 studies; inter-rater reliability: 11 studies; implementation: one study; some studies were included in two reviews). One-quarter of diagnostic accuracy studies were rated as being at a high risk of bias. In adults, MRI had high diagnostic accuracy [95.6% sensitivity, 95% confidence interval (CI) 92.4% to 97.5%; 80.7% specificity, 95% CI 70.8% to 87.8%]. PET also had high accuracy (85.1% sensitivity, 95% CI 71.5% to 92.9%; 92.8% specificity, 95% CI 83.0% to 97.1%), as did SPECT (95.1% sensitivity, 95% CI 87.8% to 98.1%; 82.0% specificity, 95% CI 61.5% to 92.8%). There was similar diagnostic performance with MRI, PET and SPECT. Scintigraphy (83.6% sensitivity, 95% CI 71.8% to 91.1%; 70.6% specificity, 57.7% to 80.8%), computed tomography (69.7% sensitivity, 95% CI 40.1% to 88.7%; 90.2% specificity, 95% CI 57.6% to 98.4%) and radiography (70.4% sensitivity, 95% CI 61.6% to 77.8%; 81.5% specificity, 95% CI 69.6% to 89.5%) all had generally inferior diagnostic accuracy. Technetium-99m hexamethylpropyleneamine oxime white blood cell scintigraphy (87.3% sensitivity, 95% CI 75.1% to 94.0%; 94.7% specificity, 95% CI 84.9% to 98.3%) had higher diagnostic accuracy, similar to that of PET or MRI. There was no evidence that diagnostic accuracy varied by scan location or cause of osteomyelitis, although data on many scan locations were limited. Diagnostic accuracy in diabetic foot patients was similar to the overall results. Only three studies in children were identified; results were too limited to draw any conclusions. Eleven studies evaluated inter-rater reliability. MRI had acceptable inter-rater reliability. We found only one study on test implementation and no evidence on patient preferences or cost-effectiveness of imaging tests for osteomyelitis.

LIMITATIONS

Most studies included < 50 participants and were poorly reported. There was limited evidence for children, ultrasonography and on clinical factors other than diagnostic accuracy.

CONCLUSIONS

Osteomyelitis is reliably diagnosed by MRI, PET and SPECT. No clear reason to prefer one test over the other in terms of diagnostic accuracy was identified. The wider availability of MRI machines, and the fact that MRI does not expose patients to harmful ionising radiation, may mean that MRI is preferable in most cases. Diagnostic accuracy does not appear to vary with the potential cause of osteomyelitis or with the body part scanned. Considerable uncertainty remains over the diagnostic accuracy of imaging tests in children. Studies of diagnostic accuracy in children, particularly using MRI and ultrasound, are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42017068511.

FUNDING

This project was funded by the National Institute for Health Research Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 61. See the NIHR Journals Library website for further project information.

Imaging for detection of osteomyelitis in people with diabetic foot ulcers: A systematic review and meta-analysis

BACKGROUND

Osteomyelitis is an infection of the bone which can occur in people with diabetic foot ulcers. It can be diagnosed using X-rays, ultrasound, scintigraphy, magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT) and positron emission tomography (PET).

OBJECTIVES

To review the evidence on the diagnostic accuracy of imaging tests to diagnose osteomyelitis in people with diabetic foot ulcers.

METHODS

We conducted a systematic review and meta-analysis. MEDLINE, EMBASE and other databases were searched to July 2018. Risk of bias was evaluated. Diagnostic accuracy was estimated using bivariate meta-analyses.

RESULTS

Thirty-six studies were included in the meta-analysis. Eight studies were at high risk of bias MRI had high diagnostic accuracy (22 studies: 96.4 % sensitivity (95 % CI 90.7-98.7); 83.8 % specificity (76.0-89.5)). PET scans also had high accuracy (6 studies: 84.3 % sensitivity (52.8-96.3); 92.8 % specificity (75.7-98.2)), and possibly also SPECT, but with few studies (3 studies: 95.6 % sensitivity (76.0-99.3); 55.1 % specificity (19.3-86.3)). Scintigraphy (17 studies: 84.2 % sensitivity (76.8-89.6); 67.7 % specificity (56.2-77.4)), and X-rays (16 studies: 61.9 % sensitivity (50.5-72.1); 78.3 % specificity (62.9-88.5)) had generally inferior diagnostic accuracy.

CONCLUSIONS

MRI and PET both reliably diagnose osteomyelitis in diabetic foot ulcer patients. SPECT may also have good diagnostic accuracy, although evidence is limited. This review confirms most current guidelines, showing that MRI may be the preferable test in most cases, given its wider availability and the lack of potentially harmful ionising radiation.

Predicting osteomyelitis in patients whose initial MRI demonstrated bone marrow edema without corresponding T1 signal marrow replacement

PURPOSE

We endeavored to determine which characteristics of diabetic ulcers portend the strongest risk for osteomyelitis in patients whose initial T1-weighted imaging was normal. By determining which features have a greater risk for osteomyelitis, clinicians can treat patients more aggressively to reduce the sequela of inadequately treated osteomyelitis.

MATERIALS AND METHODS

We performed a retrospective analysis of MR imaging from 60 pedal ulcers with suspected osteomyelitis. Ulcer dimensions and depth were measured. Ratios of marrow ROI/joint fluid ROI on T2/STIR sequences were obtained. Progression to osteomyelitis on subsequent MRI was characterized by loss of normal marrow signal on T1-weighted images. Statistical analysis was performed with a two-sample t test and Cox proportional hazard model. A p value < 0.05 was used as the threshold for statistical significance.

RESULTS

Sixty MR exams were identified. Thirty-four progressed to osteomyelitis. Marrow ROI/joint fluid ratios averaged 65% in the osteomyelitis group, and 45% in the non-osteomyelitis group, p < 0.001. ROI ratios > 53% had a 6.5-fold increased risk of osteomyelitis, p < 0.001. Proximity to bone averaged 6 mm in the osteomyelitis group and 9 mm in the non-osteomyelitis group, p = 0.02. Ulcer size averaged 4 cm² in the osteomyelitis group versus 2.4 cm² in the non-osteomyelitis group, p = 0.07. Ulcers greater than 3 cm² has a 2-fold increase in the risk of osteomyelitis, p = 0.04.

CONCLUSION

Increasing bone marrow ROI signal/joint fluid ratios on T2/STIR images were the strongest risk factors for developing osteomyelitis, while ulcer size and depth are weaker predictors.

Diagnosing Osteomyelitis: A Histology Guide for Pathologists

Histopathologic examination of bone specimens coupled with bone culture is considered the gold standard for the diagnosis of osteomyelitis (OM). Despite this, studies have demonstrated interpathologist agreement in the diagnosis of OM as low as 30%, largely stemming from a lack of specific definitions and diagnostic criteria. Review of the literature has provided insight into the lifecycle of OM, illustrating the histologic progression of OM phases from acute to chronic, and provides support for defining subcategories of OM. Using an algorithmic histopathologic tool consisting of 15 criteria, each with an associated score, we defined 5 categories of OM: (1) acute OM, (2) acute and chronic OM, (3) chronic OM, (4) chronic active OM, and (5) chronic inactive OM. We reviewed 462 microscopic slides from 263 patients with suspected OM, and for each slide, we determined an algorithm-derived diagnosis, which was then used to calculate a total histopathologic load score (Jupiter score). Algorithm-derived diagnoses recapitulated original clinical diagnoses and diagnosed cases as OM that had not been originally diagnoses. These novel cases were more likely to have subsequent clinical complications. Finally, pathologic load scores were assessed for association with the category of OM.

Osteomyelitis Increases the Rate of Amputation in Patients With Type 2 Diabetes and Lower Extremity Burns

In patients with diabetes mellitus (DM), amputation rates exceed 30% when lower extremity osteomyelitis is present. We sought to determine the rate of osteomyelitis and any subsequent amputation in our patients with DM and lower extremity burns. We performed a single-site, retrospective review at our burn center using the institutional burn center registry, linked to clinical and administrative data. Adults (≥18 years old) with DM admitted from January 1, 2014 to December 31, 2018 for isolated lower extremity burns were eligible for inclusion. We evaluated demographics, burn characteristics, comorbidities, presence of radiologically confirmed osteomyelitis, length of stay (LOS), inpatient hospitalization costs, and amputation rate at 3 months and 12 months after injury. We identified 103 patients with DM and isolated lower extremity burns. Of these, 88 patients did not have osteomyelitis, while 15 patients had radiologically confirmed osteomyelitis within 3 months of the burn injury. Compared to patients without osteomyelitis, patients with osteomyelitis had significantly increased LOS (average LOS 22.7 days vs 12.1 days, P = .0042), inpatient hospitalization costs (average $135,345 vs $62,237, P = .0008), amputation rate within 3 months (66.7% vs 5.70%, P &lt; .00001), and amputation rate within 12 months (66.7% vs 9.1%, P &lt; .0001). The two groups were otherwise similar in demographics, burn injury characteristics, access to healthcare, and preexisting comorbidities. Patients with DM and lower extremity burns incurred increased LOS, higher inpatient hospitalization costs, and increased amputation rates if radiologically confirmed osteomyelitis was present within 3 months of the burn injury.

A comparison of ferumoxytol with gadolinium as contrast agents for the diagnostic magnetic resonance imaging of osteomyelitis

BACKGROUND

Ferumoxytol, an FDA-approved superparamagnetic iron oxide nanoparticle (SPION) preparation used for the treatment of iron deficiency anemia, is also known to be taken up by macrophages in areas of infection or inflammation, where it produces negative contrast changes on T2-weighted MR images.

PURPOSE

We sought to compare Ferumoxytol-induced MRI contrast changes with those observed using standard-of-care Gadolinium in patients presenting with symptoms suggestive of osteomyelitis.

SUBJECTS

Out of eighteen enrolled patients, 15 had MR imaging with both ferumoxytol and gadolinium. Based on clinical and/or pathologic criteria, 7 patients were diagnosed with osteomyelitis, 5 patients had osteomyelitis ruled out, and in 3 patients a definitive diagnosis could not be made.

FIELD STRENGTH

1.5 Tesla.

SEQUENCES

Used included STIR, T1-weighted and T2-weighted spin echo.

ASSESSMENT

The mean contrast changes upon ferumoxytol and gadolinium administration were measured from lesion regions of interest and compared with control regions.

STATISTICAL TESTS

Student's t-test, propagation of errors. Data are reported as means ± S.E.

RESULTS

The mean contrast changes, ΔC, associated with a diagnosis of osteomyelitis were found to be ΔCFe = -2.7 ± 0.7 when Ferumoxytol and T2w imaging sequences were used and ΔCGd = +3.1 ± 1.1 (P < 0.001) when Gadolinium and a T1w imaging sequence was used. The MRI contrast changes for both agents correlated with systemic markers of inflammation, such as the erythrocyte sedimentation rate. In patients without osteomyelitis, no significant contrast changes were observed in T2-weighted, Ferumoxytol-contrasted MRI. The macrophages in osteomyelitic lesions were found to take up at least 16 times as much iron as benign bone marrow.

DATA CONCLUSION

We conclude that in terms of its MRI diagnostic accuracy for osteomyelitis Ferumoxytol-contrasted MRI is a promising approach for diagnosing osteomyelitis that merits further study.

Nuclear Medicine for the Orthopedic Foot and Ankle Surgeon

Nuclear medicine has been widely applied as a diagnostic tool for orthopedic foot and ankle pathology. Although its indications have diminished with improvements in and the availability of magnetic resonance imaging, nuclear medicine still has a significant and valuable role. The present article offers a comprehensive and current review of the most common nuclear imaging modalities for the orthopedic foot and ankle surgeon. Methods discussed include bone scintigraphy, gallium citrate scintigraphy, labeled-leukocyte scintigraphy, and single-photon emission computed tomography (SPECT). We review the indications and utility of these techniques as they pertain to specific foot and ankle conditions, including osteomyelitis, stress fractures, talar osteochondral lesions, complex regional pain syndrome, oncology, plantar fasciitis, and the painful total ankle arthroplasty. We conclude with a discussion of our approach to nuclear medicine with illustrative cases. Level of Evidence: Level V, expert opinion.

CCR5 and CCR5Δ32 in bacterial and parasitic infections: Thinking chemokine receptors outside the HIV box

The CCR5 molecule was reported in 1996 as the main HIV-1 co-receptor. In that same year, the CCR5Δ32 genetic variant was described as a strong protective factor against HIV-1 infection. These findings led to extensive research regarding the CCR5, culminating in critical scientific advances, such as the development of CCR5 inhibitors for the treatment of HIV infection. Recently, the research landscape surrounding CCR5 has begun to change. Different research groups have realized that, since CCR5 has such important effects in the chemokine system, it could also affect other different physiological systems. Therefore, the effect of reduced CCR5 expression due to the presence of the CCR5Δ32 variant began to be further studied. Several studies have investigated the role of CCR5 and the impacts of CCR5Δ32 on autoimmune and inflammatory diseases, various types of cancer, and viral diseases. However, the role of CCR5 in diseases caused by bacteria and parasites is still poorly understood. Therefore, the aim of this article is to review the role of CCR5 and the effects of CCR5Δ32 on bacterial (brucellosis, osteomyelitis, pneumonia, tuberculosis and infection by Chlamydia trachomatis) and parasitic infections (toxoplasmosis, leishmaniasis, Chagas disease and schistosomiasis). Basic information about each of these infections was also addressed. The neglected role of CCR5 in fungal disease and emerging studies regarding the action of CCR5 on regulatory T cells are briefly covered in this review. Considering the "renaissance of CCR5 research," this article is useful for updating researchers who develop studies involving CCR5 and CCR5Δ32 in different infectious diseases.

Clinical Applications for Radiotracer Imaging of Lower Extremity Peripheral Arterial Disease and Critical Limb Ischemia

Peripheral arterial disease (PAD) is an atherosclerotic occlusive disease of the non-coronary vessels that is characterized by lower extremity tissue ischemia, claudication, increased prevalence of lower extremity wounds and amputations, and impaired quality of life. Critical limb ischemia (CLI) represents the severe stage of PAD and is associated with additional risk for wound formation, amputation, and premature death. Standard clinical tools utilized for assessing PAD and CLI primarily focus on anatomical evaluation of peripheral vascular lesions or hemodynamic assessment of the peripheral circulation. Evaluation of underlying pathophysiology has traditionally been achieved by radiotracer-based imaging, with many clinical investigations focusing on imaging of skeletal muscle perfusion and cases of foot infection/inflammation such as osteomyelitis and Charcot neuropathic osteoarthropathy. As advancements in hybrid imaging systems and radiotracers continue to evolve, opportunities for molecular imaging of PAD and CLI are also emerging that may offer novel insight into associated complications such as peripheral atherosclerosis, alterations in skeletal muscle metabolism, and peripheral neuropathy. This review summarizes the pros and cons of radiotracer-based techniques that have been utilized in the clinical environment for evaluating lower extremity ischemia and common pathologies associated with PAD and CLI.

Prognosis of the outcome of severe diabetic foot ulcers with multidisciplinary care

Background: Approximately 2-4% of individuals worldwide with diabetes mellitus have foot ulcers. This study aims to assess the factors affecting the outcomes of severe foot ulcers in diabetic individuals. Methods: An analytical prospective cohort study was conducted from March 1st, 2015, to March 1st, 2017. A total of 34 individuals was selected. The study included patients with foot ulcers below the ankle who were at risk of amputation. All tests used a <5% level of significance and confidence interval of 95%. A Pearson's chi-squared test and binary multiple regression were performed to assess the factors related to healing. Results: Only 11.7% of the individuals required amputation; ulcers classified as 2/B according to the University of Texas Diabetic Foot Ulcer Classification System healed before the 1/B ulcers. Neuropathic ulcers were the most prevalent (58.8%); 61.8% healed after 1 year. Most of the individuals were overweight, 47.1% had reduced glomerular filtration rates, and 78.8% had glycated hemoglobin >7%. Body mass index and osteomyelitis were the two significant variables in logistic regression. Conclusions: In this study, osteomyelitis was the main complication related to the risk of amputation, and elevated body mass index and osteomyelitis were the significant factors that induced a slower healing time.

Trends in the Types of Physicians Performing Partial Foot Amputations

BACKGROUND

Partial foot amputations (PFAs) are often indicated for the treatment of severe infection, osteomyelitis, and critical limb ischemia, which consequently leads to irreversible necrosis. Many patients who undergo PFAs have concomitant comorbidities and generally present with a severe acute manifestation of the condition, such as gangrenous changes, systemic infection, or debilitating pain, which would then require emergency amputation on an inpatient basis.

METHODS

The purpose of this study was to track the recent prevalence of PFAs and to investigate the current demographic trends of the physicians managing and performing PFAs, specifically regarding medical degree and specialty. Doctors of podiatric medicine are striving to achieve parity with their allopathic and osteopathic surgical counterparts and become a more prominent part of the multidisciplinary approach to limb salvage and emergency surgical treatment. This study evaluated 4 years (2009-2012) of PFA data from the Pennsylvania state inpatient database in the two most populated areas of Pennsylvania: Philadelphia and Allegheny counties. Statistics on medical schools were obtained directly from the accrediting bodies of allopathic, osteopathic, and podiatric medical schools. The goal of this study was to evaluate the general trends of patients undergoing a PFA and to quantify the upswing of podiatric surgeons intervening in the surgical care of these patients.

RESULTS

The number of partial foot amputations in the United States rose from 2006 to 2012. Podiatric surgeons performed 46% of theses procedures for residents of Philadelphia County from 2009 to 2012. In Allegheny County podiatric physicians performed 42% of these procedures during the same time frame.

CONCLUSIONS

Partial foot amputations are increasing over time. Podiatric Surgeons perform a significant share of these operations. This share is increasing in the most populated areas of Pennsylvania.

Bacteriophage ZCKP1: A Potential Treatment for Klebsiella pneumoniae Isolated From Diabetic Foot Patients

The recorded growth in infection by multidrug resistant bacteria necessitates prompt efforts toward developing alternatives to antibiotics, such as bacteriophage therapy. Immuno-compromised patients with diabetes mellitus are particularly prone to foot infections by multidrug resistant Klebsiella pneumoniae, which may be compounded by chronic osteomyelitis. Bacteriophage ZCKP1, isolated from freshwater in Giza, Egypt, was tested in vitro to evaluate its lytic activity against a multidrug resistant K. pneumoniae KP/01, isolated from foot wound of a diabetic patient in Egypt. Characterization of ZCKP1 phage indicated that it belonged to the Myoviridae family of bacteriophages with a ds-DNA genome size of 150.9 kb. Bacteriophage ZCKP1 lysed a range of osteomyelitis pathogenic agents including Klebsiella spp., Proteus spp. and E. coli isolates. The bacteriophage reduced the bacterial counts of host bacteria by ≥2 log₁₀ CFU/ml at 25°C, and demonstrated the ability to reduce bacterial counts and biofilm biomass (>50%) when applied at high multiplicity of infection (50 PFU/CFU). These characteristics make ZCKP1 phage of potential therapeutic value to treat K. pneumoniae and associated bacteria present in diabetic foot patients.

Staphylococcal Osteomyelitis: Disease Progression, Treatment Challenges, and Future Directions

Osteomyelitis is an inflammatory bone disease that is caused by an infecting microorganism and leads to progressive bone destruction and loss. The most common causative species are the usually commensal staphylococci, with Staphylococcus aureus and Staphylococcus epidermidis responsible for the majority of cases. Staphylococcal infections are becoming an increasing global concern, partially due to the resistance mechanisms developed by staphylococci to evade the host immune system and antibiotic treatment. In addition to the ability of staphylococci to withstand treatment, surgical intervention in an effort to remove necrotic and infected bone further exacerbates patient impairment. Despite the advances in current health care, osteomyelitis is now a major clinical challenge, with recurrent and persistent infections occurring in approximately 40% of patients. This review aims to provide information about staphylococcus-induced bone infection, covering the clinical presentation and diagnosis of osteomyelitis, pathophysiology and complications of osteomyelitis, and future avenues that are being explored to treat osteomyelitis.

Factors Associated with a Prolonged Length of Hospital Stay in Patients with Diabetic Foot: A Single-Center Retrospective Study

BACKGROUND

We conducted this study to identify factors that may prolong the length of the hospital stay (LHS) in patients with diabetic foot (DF) in a single-institution setting.

METHODS

In this single-center retrospective study, we evaluated a total of 164 patients with DF, and conducted an intergroup comparison of their baseline demographic and clinical characteristics, including sex, age, duration of diabetes, smoking status, body mass index, underlying comorbidities (e.g., hypertension or diabetic nephropathy), wound characteristics,type of surgery, the total medical cost, white blood cell (WBC) count, C-reactive protein (CRP) levels, erythrocyte sedimentation rate, and albumin, protein, glycated hemoglobin, and 7-day mean blood glucose (BG) levels.

RESULTS

Pearson correlation analysis showed that an LHS of >5 weeks had a significant positive correlation with the severity of the wound (r=0.647), WBC count (r=0.571), CRP levels (r=0.390), DN (r=0.020), and 7-day mean BG levels (r=0.120) (P<0.05). In multiple regression analysis, an LHS of >5 weeks had a significant positive correlation with the severity of the wound (odds ratio [OR]=3.297; 95% confidence interval [CI], 1.324-10.483; P=0.020), WBC count (OR=1.423; 95% CI, 0.046-0.356; P=0.000), CRP levels (OR=1.079; 95% CI, 1.015-1.147; P=0.014), albumin levels (OR=0.263; 95% CI, 0.113-3.673; P=0.007), and 7-day mean BG levels (OR=1.018; 95% CI, 1.001-1.035; P=0.020).

CONCLUSIONS

Surgeons should consider the factors associated with a prolonged LHS in the early management of patients with DF. Moreover, this should also be accompanied by a multidisciplinary approach to reducing the LHS.

Subtotal Calcanectomy for the Treatment of Chronic Ulcer Associated with Osteomyelitis: A Case Report

INTRODUCTION

Subtotal calcanectomy is a therapeutic option for the treatment of chronic ulcer associated with calcaneal osteomyelitis. Closure of the surgical wound can be difficult due to the lack of local cutaneous coverage. We present the first case of subtotal calcanectomy in which the ankle was positioned in plantar flexion allowing the primary closure of the surgical wound without the need for flap.

CASE REPORT

We present a case of 62-year-old female patient with a foot ulcer associated with osteomyelitis. After an initial assessment, a subtotal calcanectomy with primary wound closure was performed. After healing of the surgical wound, the patient started rehabilitation with recovery of dorsiflexion and independent gait without support after 12 weeks.

CONCLUSION

The result shows that subtotal calcanectomy with the ankle in plantar flexion allows primary closure of the operative wound, without causing difficulty for rehabilitation.

Using Nuclear Medicine Imaging Wisely in Diagnosing Infectious Diseases

In recent years, there has been an increasing emphasis on efficient and accurate diagnostic testing, exemplified by the American Board of Internal Medicine’s “Choosing Wisely” campaign. Nuclear imaging studies can provide early and accurate diagnoses of many infectious disease syndromes, particularly in complex cases where the differential remains broad.

This review paper offers clinicians a rational, evidence-based guide to approaching nuclear medicine tests, using an example case of methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia in a patient with multiple potential sources. Fluorodeoxyglucose-positron emission tomography (FDG-PET) with computed tomography (CT) and sulfur colloid imaging with tagged white blood cell (WBC) scanning offer the most promise in facilitating rapid and accurate diagnoses of endovascular graft infections, vertebral osteomyelitis (V-OM), diabetic foot infections, and prosthetic joint infections (PJIs). However, radiologists at different institutions may have varying degrees of expertise with these modalities.

Regardless, infectious disease consultants would benefit from knowing what nuclear medicine tests to order when considering patients with complex infectious disease syndromes.

A retrospective study of cryopreserved umbilical cord as an adjunctive therapy to promote the healing of chronic, complex foot ulcers with underlying osteomyelitis

Complex lower extremity ulcers with exposed bone, tendon, muscle, and/or joint capsule as well as multiple comorbidities including diabetes, ischemia, and underlying osteomyelitis are difficult to heal and associated with high morbidity and mortality and high rates of amputation. A retrospective review was performed to assess healing of 31 patients presenting with 33 complex foot ulcers with a confirmed histopathological diagnosis of osteomyelitis treated by the same surgeon at a single wound care center by the following treatment regimen: sharp debridement, resection of infected bone when necessary, open cortex, antibiotics, and application of cryopreserved umbilical cord (cUC). The average ulcer size was 15.6 ± 17.7 cm² (0.4-73.95 cm² ). Overall, 26 out of the 33 wounds achieved complete closure (78.8%). Five patients were lost to follow-up and one patient expired during the course of treatment, not believed to be treatment related. Of the remaining 27 wounds in patients not lost to follow-up, 26 achieved complete healing with an average time to healing of 16 weeks and an average of 1.24 applications of cUC. The results suggest that cUC used as an adjunctive tissue therapy in conjunction with surgical debridement, resection of infected bone, open cortex, and antibiotic treatment may be an effective overall treatment strategy to promote wound healing of complex foot ulcers associated with osteomyelitis. The preliminary results are encouraging and warrant further randomized control studies to determine whether cUC might help address such an unmet medical need.