Combined clinical and laboratory testing improves diagnostic accuracy for osteomyelitis in the diabetic foot

Osteomyelitis and Septic Arthritis of the Foot and Ankle: Imaging Update

Radiography is considered the first-line screening exam for clinically suspected osteomyelitis. However, additional evaluation is generally needed. MRI is the definitive diagnostic exam with high sensitivity and specificity combined with excellent anatomic definition. Gadolinium contrast can be useful to detect areas of devitalization before surgery. Bone marrow edema on fluid-sensitive images and low signal intensity on T1-weighted images in the presence of secondary MRI findings, including ulcer, sinus tract, and cellulitis with or without abscess are typical findings of osteomyelitis. If MRI is contraindicated, three phase bone scan can be used. Early diagnosis and treatment is essential.

Update of biomarkers to diagnose diabetic foot osteomyelitis: A meta-analysis and systematic review

The aim of this study was to evaluate the diagnostic characteristics of biomarker for diabetic foot osteomyelitis (DFO). We searched PubMed, Scopus, Embase and Medline for studies who report serological markers and DFO before December 2022. Studies must include at least one of the following diagnostic parameters for biomarkers: area under the curve, sensitivities, specificities, positive predictive value, negative predictive value. Two authors evaluated quality using the Quality Assessment of Diagnostic Accuracy Studies tool. We included 19 papers. In this systematic review, there were 2854 subjects with 2134 (74.8%) of those patients being included in the meta-analysis. The most common biomarkers were erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and procalcitonin (PCT). A meta-analysis was then performed where data were evaluated with Forrest plots and receiver operating characteristic curves. The pooled sensitivity and specificity were 0.72 and 0.75 for PCT, 0.72 and 0.76 for CRP and 0.70 and 0.77 for ESR. Pooled area under the curves for ESR, CRP and PCT were 0.83, 0.77 and 0.71, respectfully. Average diagnostic odds ratios were 16.1 (range 3.6-55.4), 14.3 (range 2.7-48.7) and 6.7 (range 3.6-10.4) for ESR, CRP and PCT, respectfully. None of the biomarkers we evaluated could be rated as 'outstanding' to diagnose osteomyelitis. Based on the areas under the curve, ESR is an 'excellent' biomarker to detect osteomyelitis, and CRP and PCT are 'acceptable' biomarkers to diagnose osteomyelitis. Diagnostic odds ratios indicate that ESR, CRP and PCT are 'good' or 'very good' tools to identify osteomyelitis.

Diagnosis of infection in the foot of patients with diabetes: A systematic review

BACKGROUND

Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potential mortality and present formidable challenges in surgical and antimicrobial treatment.

METHODS

In June 2022, we searched the literature using PubMed and EMBASE for published studies on the diagnosis of diabetic foot infection (DFI). On the basis of pre-determined criteria, we reviewed prospective controlled, as well as non-controlled, studies in English. We then developed evidence statements based on the included papers.

RESULTS

We selected a total of 64 papers that met our inclusion criteria. The certainty of the majority of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot/Infectious Diseases Society of America scheme correlates with the patient's likelihood of the need for hospitalisation, lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers such as erythrocyte sedimentation rate (ESR), C-reactive protein and procalcitonin are supportive, but not diagnostic, of soft tissue infection. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Although non-culture techniques, especially next-generation sequencing, are likely to identify more bacteria from tissue samples including bone than standard cultures, no studies have established a significant impact on the management of patients with DFIs. In patients with suspected diabetic foot osteomyelitis, the combination of a positive probe-to-bone test and elevated ESR supports this diagnosis. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis (DFO), but advanced imaging methods including magnetic resonance imaging (MRI) and nuclear imaging when MRI is not feasible help in cases when either the diagnosis or the localisation of infection is uncertain. Intra-operative or non-per-wound percutaneous biopsy is the best method to accurately identify bone pathogens in case of a suspicion of a DFO. Bedside percutaneous biopsies are effective and safe and are an option to obtain bone culture data when conventional (i.e. surgical or radiological) procedures are not feasible.

CONCLUSIONS

The results of this systematic review of the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is still a need for more prospective controlled studies of high quality.

The infected diabetic foot: Modulation of traditional biomarkers for osteomyelitis diagnosis in the setting of diabetic foot infection and renal impairment

The objective of this paper was to investigate erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP) in diagnosing pedal osteomyelitis (OM) in patients with and without diabetes, and with and without severe renal impairment (SRI). This was a retrospective cohort study of patients with moderate and severe foot infections. We evaluated three groups: Subjects without diabetes (NDM), subjects with diabetes and without severe renal insufficiency (DM-NSRI), and patients with diabetes and SRI (DM-SRI). SRI was defined as eGFR <30. We evaluated area under the curve (AUC), cutoff point, sensitivity and specificity to characterize the accuracy of ESR and CRP to diagnose OM. A total of 408 patients were included in the analysis. ROC analysis in the NDM group revealed the AUC for ESR was 0.62, with a cutoff value of 46 mm/h (sensitivity, 49.0%; specificity, 76.0%). DM-NSRI subjects showed the AUC for ESR was 0.70 with the cutoff value of 61 mm/h (sensitivity, 68.9%; specificity 61.8%). In DM-SRI, the AUC for ESR was 0.67, with a cutoff value of 119 mm/h (sensitivity, 46.4%; specificity, 82.40%). In the NDM group, the AUC for CRP was 0.55, with a cutoff value of 6.4 mg/dL (sensitivity, 31.3%; specificity, 84.0%). For DM-NSRI, the AUC for CRP was 0.70, with a cutoff value of 8 mg/dL (sensitivity, 49.2%; specificity, 80.6%). In DM-SRI, the AUC for CRP was 0.62, with a cutoff value of 7 mg/dL (sensitivity, 57.1%; specificity, 67.7%). While CRP demonstrated relatively consistent utility, ESR's diagnostic cutoff points diverged significantly. These results highlight the necessity of considering patient-specific factors when interpreting ESR results in the context of OM diagnosis.

Is the duration of diabetic foot ulcers an independent risk factor for developing diabetic foot osteomyelitis?

OBJECTIVE

This study aimed to determine whether the prolonged duration of diabetic foot ulcers was associated with an increased incidence of diabetic foot osteomyelitis.

STUDY DESIGN

A retrospective cohort study METHODS: The medical records of all patients who participated in the diabetic foot clinic between January 2015 and December 2020 were reviewed. Patients with new diabetic foot ulcers were monitored for diabetic foot osteomyelitis. The collected data included the patient's profile, comorbidities and complications, the ulcer profile (area, depth, location, duration, number of ulcers, inflammation, and history of the previous ulcer), and outcome. Univariate and multivariate Poisson regression analyses were used to assess risk variables for diabetic foot osteomyelitis.

RESULTS

Eight hundred and fifty-five patients were enrolled; 78 developed diabetic foot ulcers (cumulative incidence 9% over 6 years, average annual incidence 1.5%) and among these diabetic foot ulcers, 24 developed diabetic foot osteomyelitis (cumulative incidence 30% over 6 years, average annual incidence of 5%, incidence rate 0.1/person-year). Statistically significant risk factors for the development of diabetic foot osteomyelitis were ulcers that were deep to the bone (adjusted risk ratio 2.50, p = 0.04) and inflamed wounds (adjusted risk ratio 6.20, p = 0.02). The duration of diabetic foot ulcers was not associated with diabetic foot osteomyelitis (adjusted risk ratio 1.00, p = 0.98).

CONCLUSION

The duration was not an associated risk factor for diabetic foot osteomyelitis, while bone-deep ulcers and inflamed ulcers were found to be significant risk factors for the development of diabetic foot osteomyelitis.

Serum Inflammatory Markers and Amputations in Hand Osteomyelitis: A Retrospective Review of 146 Cases

BACKGROUND

The diagnosis of hand osteomyelitis requires correlation of clinical, radiological, and microbiological findings. The role of serum inflammatory markers in diagnosing and prognosticating hand osteomyelitis remains uncertain. We sought to determine the utility of inflammatory markers in the diagnosis and follow-up of hand osteomyelitis, and their ability to predict outcomes, particularly amputation.

METHODS

We retrospectively reviewed 146 patients diagnosed with hand osteomyelitis and with serum inflammatory marker levels measured after the onset of symptoms and within 14 days either side of diagnosis. Blood results at first presentation including white cell count (WCC), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and C-reactive protein (CRP) were reviewed, and associations with amputations assessed. Follow-up markers taken at 15 to 60 days from diagnosis were analyzed where available.

RESULTS

Mean WCC and CRP at diagnosis were 9.2 (SD: 4.6) and 30.2 (SD: 42.4) respectively, compared with 8.2 (SD: 3.9) and 30.2 (SD: 42.4) at follow-up. At diagnosis, sensitivity of CRP was 74%, and WCC was 31%. Each marker had a low positive predictive value for amputation at diagnosis (<29%). A rise in CRP between diagnosis and follow-up was associated with an increased risk of amputation compared with a fall in CRP. The finding that WCC and CRP were both normal at diagnosis had a high negative predictive value against amputation (96%).

CONCLUSION

C-reactive protein has a higher sensitivity than WCC, NLR, and PLR when used as a diagnostic adjunct in hand osteomyelitis. White cell count and CRP both within reference ranges at diagnosis was highly negatively predictive against amputation.

Osteomyelitis and Septic Arthritis of the Foot and Ankle: Imaging Update

Radiography is considered the first-line screening exam for clinically suspected osteomyelitis. However, additional evaluation is generally needed. MRI is the definitive diagnostic exam with high sensitivity and specificity combined with excellent anatomic definition. Gadolinium contrast can be useful to detect areas of devitalization before surgery. Bone marrow edema on fluid-sensitive images and low signal intensity on T1-weighted images in the presence of secondary MRI findings, including ulcer, sinus tract, and cellulitis with or without abscess are typical findings of osteomyelitis. If MRI is contraindicated, three phase bone scan can be used. Early diagnosis and treatment is essential.

Inflammatory response in confirmed non-diabetic foot and ankle infections: A case series with normal inflammatory markers

BACKGROUND

The distinction between foot and ankle wound healing complications as opposed to infection is crucial for the appropriate and efficacious allocation of antibiotic therapy. Multiple reports have focused on the diagnostic accuracy of different inflammatory markers, however, mainly in the diabetic population.

AIM

To evaluate the diagnostic accuracy of white cell count (WCC) and C-reactive protein (CRP) as diagnostic tools for this distinction in the non-diabetic cohort.

METHODS

Data was reviewed from a prospectively maintained Infectious Diseases Unit database of 216 patients admitted at Leicester University Hospitals–United Kingdom with musculoskeletal infections over the period between July 2014 and February 2020 (68 mo). All patients with confirmed diagnosis of diabetes were excluded while only those with confirmed microbiological or clinical diagnosis of foot or ankle infection were included in our study. For the included patients, we retrospectively retrieved the inflammatory markers (WCCs and CRP) at the time of presentation. Values of CRP 0-10 mg/L and WCC 4.0-11.0 × 10⁹/L were considered normal.

RESULTS

After exclusion of patients with confirmed diabetes, 25 patients with confirmed foot or ankle infections were included. All infections were confirmed microbiologically with positive intra-operative culture results. 7 (28%) patients with osteomyelitis (OM) of the foot, 11 (44%) with OM of the ankle, 5 (20%) with ankle septic arthritis and 2 (8%) patients with post-surgical wound infection were identified. Previous bony surgery was identified in 13 (52%) patients, either a corrective osteotomy or an open reduction and internal fixation for a foot or ankle fracture with the infection developing on top of the existing metalwork. 21 (84%) patients did have raised inflammatory markers while 4 (16%) patients failed to mount an inflammatory response even with subsequent debridement and removal of metal work. CRP sensitivity was 84%, while WCC sensitivity was only 28%.

CONCLUSION

CRP has a relatively good sensitivity in the diagnosis of foot and ankle infections in non-diabetic patients, whereas WCC is a poor inflammatory marker in the detection of such cases. In presence of clinically high level of suspicion of foot or ankle infection, a normal CRP should not rule out the diagnosis of OM.

Classification Model for Diabetic Foot, Necrotizing Fasciitis, and Osteomyelitis

Simple Summary

Necrotizing fasciitis (NF) and osteomyelitis (OM) are severe complications in patients with diabetic foot ulcers (DFUs). Although NF and OM often cause results including limb amputation and death, definite diagnoses of these are challenging. To aid the prompt and proper diagnosis of NF and OM in patients with DFU, we developed and evaluated a novel prediction model based on machine learning technology. In summary, our prediction model appropriately discriminated the NF and OM from diabetic foot. Moreover, this prediction model has advantages in that it is based on the demographic data and routine laboratory results, which requires no additional examinations which are complicated or expensive.

Abstract

Diabetic foot ulcers (DFUs) and their life-threatening complications, such as necrotizing fasciitis (NF) and osteomyelitis (OM), increase the healthcare cost, morbidity and mortality in patients with diabetes mellitus. While the early recognition of these complications could improve the clinical outcome of diabetic patients, it is not straightforward to achieve in the usual clinical settings. In this study, we proposed a classification model for diabetic foot, NF and OM. To select features for the classification model, multidisciplinary teams were organized and data were collected based on a literature search and automatic platform. A dataset of 1581 patients (728 diabetic foot, 76 NF, and 777 OM) was divided into training and validation datasets at a ratio of 7:3 to be analyzed. The final prediction models based on training dataset exhibited areas under the receiver operating curve (AUC) of the 0.80 and 0.73 for NF model and OM model, respectively, in validation sets. In conclusion, our classification models for NF and OM showed remarkable discriminatory power and easy applicability in patients with DFU.

Pilot study of the diagnostic value of CRP:albumin ratio for osteomyelitis in patients with diabetic foot ulcers

OBJECTIVE

Osteomyelitis may complicate diabetic foot ulcers (DFUs). As a new inflammation-based prognostic factor, CRP:albumin ratio's significance is not known in osteomyelitis among patients with or without diabetes.

METHOD

Patients with type 2 diabetes and DFUs were divided into two groups: group 1 (n=47) comprised patients without osteomyelitis, and group 2 (n=50) comprised patients with osteomyelitis.

RESULTS

Erythrocyte sedimentation rate (ESR) (88.5±23.0 versus 42.0±22.2), white blood cell count (WBC) (14.7±6.9x10³ versus 10.0±4.4x10³), C-reactive protein (CRP) level (15.6±9.9 versus 2.4±3.3) and CRP:albumin ratio (6.6±4.9 versus 0.7±1.0) were significantly higher, and albumin level was significantly lower in group 2 compared to group 1 (p<0.001 for all). The presence of osteomyelitis was significantly and positively correlated with ESR (r=0.721; p<0.001), WBC (r=0.380; p<0.001), CRP (r=0.667; p<0.001) and CRP:albumin ratio (r=0.638; p<0.001), and negatively correlated with albumin (r=-0.590; p<0.001). A CRP:albumin ratio of 1.74 or above could predict osteomyelitis with 92.0% sensitivity, 80.9% specificity, and the best area under the curve (AUC) score (AUC=0.957; 95% CI: 0.924-0.991). ESR (odds ratio (OR): 1.071 (1.025-1.119); p=0.02) and CRP:albumin ratio (OR: 2.65 (1.437-4.885); p=0.002) were independent predictors in the final model for stepwise linear regression analyses for the estimation of osteomyelitis.

CONCLUSION

CRP:albumin ratio is a cheap and repeatable inflammatory marker and can successfully detect osteomyelitis in patients with DFU.

Advances in pharmacotherapy for diabetic foot osteomyelitis

Introduction: The diagnosis of diabetic foot osteomyelitis (DFO) is usually clinical. Its severity is related to the location and depth of the lesion, and the presence of necrosis or gangrene. The aetiology of diabetic foot osteomyelitis (DFO) is usually polymicrobial, and DFO is often associated with chronic or recurring ulceration.Areas covered: We built on the  International Working Group on the Diabetic Foot (IWGDF) guidelines on the management of diabetic foot infection, providing an outline of the current and new concepts in pharmacotherapy in DFO. We assess future strategies in both medical, surgical and combination management of DFO.Expert opinion: Surgical removal of infected bone is considered as the standard treatment, but a medical approach of certain selected situations has now proven efficacy in selected patients. The combination of new modalities in local antibiotic delivery may provide better long-term solutions and more lasting remission and avoid the disadvantages of prolonged systemic antibiotics.

Diagnostic value of procalcitonin, erythrocyte sedimentation rate (ESR), quantitative C-reactive protein (CRP) and clinical findings associated with osteomyelitis in patients with diabetic foot

BACKGROUND

The diagnosis of osteomyelitis is a key step of diabetic foot management. Procalcitonin (PCT) is a novel infection marker. This study aimed to investigate the diagnostic value of procalcitonin and other conventional infection markers and clinical findings in diagnosis of osteomyelitis in diabetic foot patients.

METHODS AND MATERIALS

This diagnostic value study was carried out on ninety patients with diabetic infected foot ulcers admitted in Kashan Beheshti Hospital, 2016. After obtaining consent, 10 cc blood sample was taken for measuring serum PCT, CBC, ESR, CRP and FBS. Clinical characteristics of the wounds were noted. Magnetic resonance imaging of the foot was performed in all patients to diagnose osteomyelitis. All statistical analyses were done with the use of SPSS-16.

RESULTS

PCT levels were 0.13 ± 0.02 ng/mili patients with osteomyelitis (n= 45) and 0.04 ± 0.02 ng/ml in patients without osteomyelitis (n= 45). PCT, Erythrocyte sedimentation rate and C-reactive protein was found significantly higher in patients with osteomyelitis (p< 0.001). The ROC curve was calculated for PCT. The area under the ROC curve for infection identification was 1 (p< 0.001). The best cut-off value for PCT was 0.085 ng/ml. Sensitivity, specificity, and positive and negative predictive values were 100%, 97.8%,97.8% and 100%, respectively.

CONCLUSION

In this group of patients, PCT was useful to discriminate patients with bone infection. Also, Erythrocyte sedimentation rate and C-reactive protein can be used as a marker of osteomyelitis in diabetic patients.

Predictors of positive bone cultures from CT-guided bone biopsies performed for suspected osteomyelitis

INTRODUCTION

Bone biopsies are often used to direct antibiotic choice in patients with suspected osteomyelitis. The aim of this study was to identify the best predictors of positive bone biopsy cultures.

METHODS

A retrospective review of 845 patients who underwent computed tomography (CT)-guided non-spine bone biopsies at a tertiary academic healthcare institution. Thirty-seven patients (4.4%) had biopsies performed for suspected osteomyelitis. Laboratory markers, as well as imaging features, were measured. t-Tests and Fisher's exact tests were used to compare clinical and demographic variables between patients with positive bone cultures and patients with negative bone cultures. Multivariable logistic regression was used to identify the best predictors of bone culture positivity.

RESULTS

All patients had negative blood cultures; however, only eight patients (21.6%) had positive bone cultures, with Staphyloccocus the most common organism. Multivariable logistic regression analysis showed that an open wound (OR = 14.00, 95% CI (1.74, 112.4), p = 0.013) and any fluid aspirated at the time of biopsy (OR = 10.50, 95% CI (1.21, 91.01), p = 0.033) were the best predictors of bone culture positivity. The area under the curve (AUC) for this multivariable model was 0.784 with sensitivity and specificity of 0.778 and 0.778, respectively. Interestingly, and contrary to popular belief, open wounds with exposed bone did not always yield positive bone cultures, and when cultures were positive, were not polymicrobial.

CONCLUSIONS

Aspiration of fluid at the time of biopsy and the presence of an open wound are the best predictors of positive bone cultures.

Diagnosis of infection in the foot in diabetes: a systematic review

BACKGROUND

Securing an early accurate diagnosis of diabetic foot infections and assessment of their severity are of paramount importance since these infections can cause great morbidity and potentially mortality and present formidable challenges in surgical and antimicrobial treatment.

METHODS

In June 2018, we searched the literature using PuEbMed and EMBASE for published studies on the diagnosis of diabetic foot infection. On the basis of predetermined criteria, we reviewed prospective controlled, as well as noncontrolled, studies in any language, seeking translations for those not in English. We then developed evidence statements on the basis of the included papers.

RESULTS

From the 4242 records screened, we selected 35 papers that met our inclusion criteria. The quality of all but one of the evidence statements was low because of the weak methodology of nearly all of the studies. The available data suggest that diagnosing diabetic foot infections on the basis of clinical signs and symptoms and classified according to the International Working Group of the Diabetic Foot scheme correlates with the patient's likelihood of ulcer healing, of lower extremity amputation, and risk of death. Elevated levels of selected serum inflammatory markers are supportive, but not diagnostic, of soft tissue or bone infection. In patients with suspected diabetic foot osteomyelitis, both a positive probe-to-bone test and an elevated erythrocyte sedimentation rate are strongly associated with its presence. Culturing tissue samples of soft tissues or bone, when care is taken to avoid contamination, provides more accurate microbiological information than culturing superficial (swab) samples. Plain X-ray remains the first-line imaging examination when there is suspicion of diabetic foot osteomyelitis, but advanced imaging methods help in cases when either the diagnosis or the localization of infection is uncertain.

CONCLUSION

The results of this first reported systematic review on the diagnosis of diabetic foot infections provide some guidance for clinicians, but there is a need for more prospective controlled studies of high quality.

Management of diabetic foot infections in the light of recent literature and new international guidelines

Introduction: In May 2019 the International Working Group on the Diabetic Foot (IWGDF) launched their quadrennially updated guidelines on the management of diabetic foot infections (DFIs). Concomitantly, the number of new publications regarding DFI increased.Areas covered: The IWGDF committee developed and addressed key questions and produced evidence-based recommendations related to diagnosing and treating DFIs. This narrative review provides an overview of this new guideline and also of other recently published literature in the field of DFIs.Expert opinion: The 2019 IWGDF guidelines provide an authoritative, international, evidence-based approach to diagnosing and treating DFIs. The 27 recommendations are supported by systematic reviews of both diagnosis and interventions. Our review of this guideline, along with other recent publications in the field, allows us to offer state-of-the-art guidance for caring for these difficult infections. As the evidence base for management of DFIs remains suboptimal, we need further research to improve the management of DFIs.

Erythrocyte Sedimentation Rate and C-Reactive Protein in Acute Inflammation

OBJECTIVES

To assess the diagnostic accuracy of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in acute inflammation.

METHODS

PubMed and Scopus were searched and eligible articles were screened for methodologic quality using the Quality Assessment of the Diagnostic Accuracy Studies-Revised. Meta-analysis with calculation of pooled sensitivity (Se), specificity (Sp), and summary area under the curve (SAUC) was performed.

RESULTS

Twenty-nine studies were eligible. Se and Sp were 0.78 and 0.68 (SAUC = 0.80) for ESR in orthopedic infections and 0.79 and 0.70 (SAUC = 0.81) for CRP. For the diagnosis of other various inflammatory conditions, CRP had a superior diagnostic accuracy, with a Se of 0.86, Sp of 0.67, and SAUC of 0.86 compared with a Se of 0.77, Sp of 0.59, and SAUC of 0.75 for ESR. Heterogeneity among studies was elevated. Combined use of ESR and CRP yielded higher diagnostic accuracy.

CONCLUSIONS

Despite observed heterogeneity among studies, ESR and CRP have a similar diagnostic accuracy in assessment of inflammation, especially in orthopedic conditions.

Calcaneal Osteomyelitis: Current Treatment Concepts

Calcaneal osteomyelitis can be a debilitating disease if proper treatment protocols are not initiated. This literature review details the epidemiology, clinical, diagnostic, and prognostic factors, and medical management in those who developed this disease.

A systematic review showing the lack of diagnostic criteria and tools developed for lower-limb cellulitis

BACKGROUND

Cellulitis can be a difficult diagnosis to make. Furthermore, 31% of patients admitted from the emergency department with suspected lower-limb cellulitis have been misdiagnosed, with incorrect treatment potentially resulting in avoidable hospital admission and the prescription of unnecessary antibiotics.

OBJECTIVES

We sought to identify diagnostic criteria or tools that have been developed for lower-limb cellulitis.

METHODS

We conducted a systematic review using Ovid MEDLINE and Embase databases in May 2018, with the aim of describing diagnostic criteria and tools developed for lower-limb cellulitis, and we assessed the quality of the studies identified using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. We included all types of study that described diagnostic criteria or tools.

RESULTS

Eight observational studies were included. Five studies examined biochemical markers, two studies assessed imaging and one study developed a diagnostic decision model. All eight studies were considered to have a high risk for bias in at least one domain. The quantity and quality of available data was low and results could not be pooled owing to the heterogeneity of the findings.

CONCLUSIONS

There is a lack of high-quality publications describing criteria or tools for diagnosing lower-limb cellulitis. Future studies using prospective designs, validated in both primary and secondary care settings, are needed. What's already known about this topic? Diagnosing lower-limb cellulitis on first presentation is challenging. Approximately one in three patients admitted from the emergency department with suspected lower-limb cellulitis do not have cellulitis and are given another diagnosis on discharge. Consequently, this results in potentially avoidable hospital admissions and the prescription of unnecessary antibiotics. There are no diagnostic criteria available for lower-limb cellulitis in the U.K. What does this study add? This systematic review has identified a key research gap in the diagnosis of lower-limb cellulitis. There is a current lack of robustly developed and validated diagnostic criteria or tools for use in clinical practice.

What Is the Best Method to Differentiate Acute Charcot Foot From Acute Infection?

RECOMMENDATION

Differentiation between acute Charcot neuroarthropathy (CN) and acute infection/osteomyelitis is complex and requires multiple (>1) diagnostic criteria. These criteria include an emphasis on the presence of neuropathy, history, and physical examination. The absence of skin wounds and resolution of swelling/erythema with elevation makes the likelihood of infection very low. In unclear cases, laboratory testing, histologic examination and culturing of bone specimens, scintigraphy, and imaging, especially magnetic resonance imaging (MRI), may be of benefit.

LEVEL OF EVIDENCE

Moderate.

DELEGATE VOTE

Agree: 100%, Disagree: 0%, Abstain: 0% (Unanimous, Strongest Consensus).

What are the Optimal Cutoff Values for ESR and CRP to Diagnose Osteomyelitis in Patients with Diabetes-related Foot Infections?

BACKGROUND

Distinguishing osteomyelitis from soft-tissue infection of the foot is important because osteomyelitis is associated with more operations, amputation, and prolonged antibiotic exposure. Both erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are routinely ordered inflammatory biomarkers for evaluating foot infection. When initial evaluation is inconclusive, advanced imaging is indicated, and high clinical or radiographic suspicion of osteomyelitis may indicate bone biopsy to identify organisms and antibiotic sensitivity. Although ESR and CRP levels are helpful for distinguishing osteomyelitis from soft-tissue infections in patients with diabetes-related foot infections, parameters regarding optimal cutoff values for those tests have not, to our knowledge, been defined.

QUESTIONS/PURPOSES

(1) What are the optimal cutoff values for ESR and CRP to differentiate osteomyelitis from soft-tissue infection in patients with diabetes-related foot infection? (2) Can a diagnostic algorithm be derived to guide interpretation of ESR and CRP to improve recognition of osteomyelitis in the setting of diabetic foot infection?

METHODS

The medical records of 1842 patients between 18 and 89 years of age treated at our institution between January 1, 2010 and February 6, 2017 for foot infection were reviewed. For inclusion, patients must have had a diagnosis of diabetes mellitus, moderate or severe infection, ESR and CRP values within 72 hours of admission, either advanced imaging (MRI or single-positron emission computed tomography/computed tomography [SPECT/CT]) or bone biopsy during admission and must not have had comorbidities that could affect ESR and CRP, such as autoimmune disorders. As such, 1489 patients were excluded, and 353 patients were included in the study. Osteomyelitis was diagnosed by positive bone culture or histopathology. Osteomyelitis was considered to be absent if there was a negative MRI or SPECT/CT result, or negative bone culture and histology findings if imaging was inconclusive. We identified 176 patients with osteomyelitis and 177 with soft-tissue infection. A blinded investigator performed the statistics. Optimal cutoffs of ESR and CRP were determined using receiver operative characteristic (ROC) analysis. A diagnostic algorithm was determined using epidemiologic principles of screening evaluations.

RESULTS

An ESR of 60 mm/h and a CRP level of 7.9 mg/dL were determined to be the optimal cutoff points for predicting osteomyelitis based on results of the ROC analysis. The ESR threshold of 60 mm/h demonstrated a sensitivity of 74% (95% confidence interval [CI], 67-80) and specificity of 56% (95% CI, 48-63) for osteomyelitis, whereas the CRP threshold of 7.9 mg/dL had a sensitivity of 49% (95% CI, 41-57) and specificity of 80% (95% CI, 74-86). If the ESR is < 30 mm/h, the likelihood of osteomyelitis is low. However, if ESR is > 60 mm/h and CRP level is > 7.9 mg/dL, the likelihood of osteomyelitis is high, and treatment of suspected osteomyelitis should be strongly considered.

CONCLUSIONS

While ESR is better for ruling out osteomyelitis initially, CRP helps distinguish osteomyelitis from soft-tissue infection in patients with high ESR values. Further prospective studies addressing the prognostic value of ESR and CRP are needed, and a more comprehensive diagnostic algorithm should be developed to include other diagnostic tests such as probe-to-bone and imaging.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Retrospective analysis of diabetic foot osteomyelitis management and outcome at a tertiary care hospital in the UK

Objectives

This study aimed to analyse retrospectively management and outcomes of the diabetic foot osteomyelitis (DFOM) multi-disciplinary team at St Thomas’ Hospital, London.

Methods

Patients admitted during 2015 with diagnosis of DFOM were included. Data were obtained from medical and microbiology records.

Results

275 patients were admitted for DF infection in 2015: 45.1% had OM (75% males). 40% were newly diagnosed with DF ulcer (DFU). 81% patients had X-ray and 28% had MRI. Bone infection was confirmed by MC&S in 53% cases. 930 microbiological isolates were obtained: 63% were Gram-positive microorganisms [S.aureus and MRSA (~40%), CoNS (20%), and E.faecalis (8%)]. All MRSA were vancomycin and linezolid sensitive. 23.2% isolates were vancomycin-resistant enterococci. 24% isolates were Gram-negative organisms: P.aeruginosa (42%), E.coli (13%), and E.cloacae (12%). Meropenem resistance was low; 5.4% P.aeruginosa, 87.5% A.baumanii. 76% patients received co-amoxiclav; 41% received ≥3 antibiotics; 17% received >3 months antibiotics. Hospital mean-length of stay was 26.1 days. Ulcer time-to-heal was >6 months in 25% patients. 22% ulcers healed without surgery, 60% healed after minor amputation, 12% patients had major amputation.

Conclusion

Despite current MDT approach, many patients progress to amputation. DF-OM still represents a challenging clinical condition, requiring further study to develop better management guidelines.

Diagnostic Utility of Erythrocyte Sedimentation Rate and C-Reactive Protein in Osteomyelitis of the Foot in Persons Without Diabetes

The aim of the study was to assess the diagnostic value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels in differentiating foot osteomyelitis (OM) from soft tissue infection (STI) in persons without diabetes. We evaluated 102 patients in a retrospective cohort study of nondiabetic patients admitted to our institution with OM (n = 51) and with STI (n = 51). Patient diagnosis was determined through bone culture and/or histopathology for OM and magnetic resonance scan and/or single-photon emission computed tomography for STI. Cutoffs for ESR and CRP to predict OM as identified by receiver operating characteristic were 45.5 mm/h and 3.45 mg/dL, respectively. The ESR cutoff demonstrated a sensitivity and specificity of 49% and 79%, while the values for CRP were 45% and 71%, respectively. The combined sensitivity and specificity for ESR and CRP were 33% and 84%. The positive and negative predictive values were 68% and 60% for ESR and 61% and 56% for CRP, respectively. In conclusion, ESR and CRP demonstrate poor sensitivity and specificity for detecting OM in the nondiabetic foot. These markers have little diagnostic utility in the nondiabetic foot.

Level of Agreement With a Multi-Test Approach to the Diagnosis of Diabetic Foot Osteomyelitis

Although bone biopsy has historically been considered the "gold standard" or "standard reference" for the diagnosis of diabetic foot osteomyelitis, some contemporary investigations have provided evidence against this as a single diagnostic test and in support of a combination of clinical, laboratory, and radiographic findings. The objective of this investigation was to measure the level of agreement between several commonly used forms of diagnostic testing for diabetic foot osteomyelitis. A retrospective chart review was performed of 50 consecutive patients admitted to a single tertiary healthcare center with the documented performance of 1) a clinical probe-to-bone test on hospital admission; 2) plain film radiographs prior to any surgical intervention; 3) magnetic resonance imaging prior to any surgical intervention; and an intraoperative excisional bone debridement performed, with samples sent for both 4) histologic analysis and 5) microbiologic analysis. A frequency count of agreement among these 5 tests was performed, and the interobserver (or inter-test) agreement was measured using the kappa statistic. We observed low levels of inter-test agreement between the 5 diagnostic tests (range 42.0%-62.0%), and levels of chance-corrected agreement were well below what would be considered appropriate for a "gold standard" or "standard reference." Levels of the kappa statistic ranged from 0.0 to 0.220, with most inter-test comparisons falling in the "poor agreement" and "slight agreement" interpretation ranges. The highest level of agreement occurred between the plain film radiographs and magnetic resonance imaging (62.0% agreement and kappa statistic of 0.220). Although it is likely that a combination of clinical, radiographic, and laboratory tests provides the best diagnostic approach for diabetic foot osteomyelitis, the data provided herein indicate that the tests themselves might have high intrinsic levels of unreliability and that the specific combination of tests that might be best used remains unclear.

Acute Cardiac Events in Patients With Severe Limb Infection

Recent studies have shown an association between infections, such as influenza, pneumonia, or bacteremia, and acute cardiac events. We studied the association between foot infection and myocardial infarction, arrhythmia, and/or congestive heart failure. We analyzed the records of 318 consecutive episodes of deep soft tissue infection, gangrene, and/or osteomyelitis in 274 patients referred to a vascular surgery service at a tertiary center. We identified 24 acute cardiac events in 21 of 318 (6.6%) episodes of foot infection or foot gangrene. These 24 events included 11 new myocardial infarctions (3.5%), 8 episodes of new onset or worsening congestive heart failure (2.5%), and 5 new arrhythmias (1.6%). Tachycardia and systemic inflammatory response syndrome were associated with acute cardiac events ( P < .05 for each). The 1-year survival of patients with acute cardiac events was 50.4%, significantly lower than the 91.7% 1-year survival of patients without acute cardiac events ( P < .0015). Acute cardiac complications are not uncommon among patients presenting with severe foot infection and are associated with a high 1-year mortality. Primary care physicians, cardiologists, and vascular and orthopedic surgeons must keep a high index of suspicion for the occurrence of an acute cardiac event.

Medical Imaging and Laboratory Analysis of Diagnostic Accuracy in 107 Consecutive Hospitalized Patients With Diabetic Foot Osteomyelitis and Partial Foot Amputations

The primary aim of our study was to compare the preoperative diagnostic accuracy of plain radiographic findings with the accuracy of magnetic resonance imaging (MRI) findings for diabetic foot osteomyelitis in hospitalized patients who underwent first-time partial foot amputations with confirmed histopathological specimens positive for osteomyelitis. Second, it was desired to determine whether certain variables within the initial clinical presentation and preoperative laboratory findings were associated with more accurate diagnosis of diabetic foot osteomyelitis in this study population. Finally, it was desired to determine the most common bacterial organisms found in bone and soft-tissue cultures taken intraoperatively and to determine how often the same organism was found in both. After applying the inclusion and exclusion criteria to the initial 329 patients identified through chart review, the final sample size for further analysis was n =107. In this study, after adjusting for the effects of covariates such as age, erythrocyte sedimentation rate (ESR) and C-reactive protein, plain radiographs seemed to have statistically more significant power than MRI in predicting and diagnosing diabetic foot osteomyelitis. In addition, higher ESR values were confirmed to predict a higher chance of positive diagnosis for diabetic foot osteomyelitis. Furthermore, the presence of positive bacterial identification from intraoperative bone cultures did not always indicate true osteomyelitis on histopathological examination.

LEVELS OF EVIDENCE

Level II: Diagnostic study.

Diabetic foot management: multidisciplinary approach for advanced lesion rescue

The diabetic foot is a complication of diabetes affecting 15% of diabetics in their lives. It is associated to diabetic neuropathy and peripheral vascular disease and its incidence has increased. The ulceration is the initial cause of a dramatic process leading, if not correctly treated, to amputations. Both neuropathy, neuro-ischemia and infections have a role in determining healing or worsening of the lesions and 85% of all amputations in diabetic patients are preceded by a foot ulceration deteriorating to a severe gangrene or infection. The different causative agents and the different clinical presentations of diabetic foot ask a multidisciplinary approach in order to address treatments to the final goals, the prevention of the amputations and the maintenance of a functional foot able with weight-bearing ability. Many professional figures, diabetologists, surgeons (both general and vascular and orthopedics), interventional radiologists, infectious diseases specialists, specialized nurses, podiatrists, orthotic technicians, are called to apply their knowledges to the diabetic patients affected by diabetic foot in a virtuous circle leading to reach the goals, with the imperative action of the multidisciplinary team. The so organized center will allow both a correct and rapid diagnosis, the use in ambulatorial environments of modern tools, or the hospitalization in multitasking wards, in which all the complications and the necessary treatments are possible, both in emergencies or in elective way, considering both revascularizations and surgery.

Inpatient Management of Diabetic Foot Infections: A Review of the Guidelines for Hospitalists

Diabetic foot infections (DFIs) are common and represent the leading cause for hospitalization among diabetic complications. Without proper management, DFIs may lead to amputation, which is associated with a decreased quality of life and increased mortality. However, there is currently significant variation in the management of DFIs, and many providers fail to perform critical prevention and assessment measures. In this review, we will provide an overview of the diagnosis, management, and discharge planning of hospitalized patients with DFIs to guide hospitalists in the optimal inpatient care of patients with this condition.

Predictive Laboratory Findings of Lower Extremity Amputation in Diabetic Patients: Meta-analysis

Lower extremity amputation is a source of morbidity and mortality among diabetic patients. This meta-analysis aimed to identify significant laboratory data in patients with diabetic foot ulcer with high rates of lower extremity amputation. We performed a systematic literature review and meta-analysis using MEDLINE, EMBASE, and Cochrane databases. We extracted and evaluated 11 variables from the included studies based on amputation rates. This study used the Newcastle-Ottawa Scale to assess the quality of the studies. The search strategy identified 101 publications from which we selected 16 articles for review. We identified HbA1c, fasting blood glucose, white blood cells, C-reactive protein, and erythrocyte sedimentation rate as predictive variables of higher major amputation rate. Although further investigation of long-term and prospective studies is needed, we identified 5 variables as predisposing factors for higher major amputation in diabetic patients through meta-analysis.

Osteomyelitis in diabetic foot: A comprehensive overview

Foot infection is a well recognized risk factor for major amputation in diabetic patients. The osteomyelitis is one of the most common expression of diabetic foot infection, being present approximately in present in 10%-15% of moderate and in 50% of severe infectious process. An early and accurate diagnosis is required to ensure a targeted treatment and reduce the risk of major amputation. The aim of this review is to report a complete overview about the management of diabetic foot osteomyelitis. Epidemiology, clinical aspects, diagnosis and treatment are widely described according to scientific reccomendations and our experience.

Revisional Surgery of the Diabetic Charcot Foot and Ankle

Charcot neuroarthropathy (CN) is a difficult problem for the foot and ankle surgeon. If surgery is required, little is known or available regarding the best methods and timing. When the initial attempt of reconstruction fails, revision of CN is even more demanding. One must take in to account all aspects, including nutrition, vascular status, infection control, short- and long-term blood glucose management, as well as other factors requiring laboratory monitoring and consult services. Once optimized, the biomechanics of the deformity can be addressed and decisions can be made on fixation devices.

Outcomes of Osteomyelitis in Patients Hospitalized With Diabetic Foot Infections

BACKGROUND

This study was conducted to evaluate the outcomes of patients with diabetic foot osteomyelitis (DFO) compared to diabetic foot soft tissue infections (STIs).

METHODS

229 patients who were hospitalized with foot infections were retrospectively reviewed, identifying 155 patients with DFO and 74 patients with STI. Primary outcomes evaluated were the rates of amputations and length of hospital stay. DFO was confirmed by the presence of positive bone culture and/or histopathology.

RESULTS

Patients with DFO had a 5.6 times higher likelihood of overall amputation (P < .0001), a 3.4 times higher likelihood of major amputation (P = .027) and a 4.2 times higher likelihood of minor amputation (P < .0001) compared to patients without DFO. Major amputation was performed in 16.7% patients diagnosed with DFO and 5.3% of patients diagnosed with STI. Patients with DFO complicated by Charcot neuroarthropathy had a 7 times higher likelihood of undergoing major amputation (odds ratio 6.78, 95% confidence interval 2.70-17.01, P < .0001). The mean hospital stay was 7 days in DFO and 6 days in patients with DFI (P = .0082). Patients with DFO had a higher erythrocyte sedimentation rate (85 vs 71, P = .02) than patients with STI, however the differences in C-reactive protein (13.4 vs 11.8, P = .29) were not significantly different.

CONCLUSION

In this study of moderate and severe DFIs, the presence of osteomyelitis resulted in a higher likelihood of amputation and longer hospital stay. Readers should recognize that the findings of this study may not be applicable to less severe cases of DFO that can be effectively managed in an outpatient setting.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Erythrocyte sedimentation rate and C-reactive protein to monitor treatment outcomes in diabetic foot osteomyelitis

This study sought to evaluate the effectiveness of the inflammatory markers, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), in monitoring treatment of osteomyelitis in the diabetic foot. We screened 150 charts of patients admitted to our hospital with diabetic foot osteomyelitis (DFO), confirmed by positive results of bone culture and/or histopathology. We included patients who had an initial ESR/CRP within 72 hours of admission and two reported follow-up values. We dichotomised patients based on the outcomes wound healing, re-infection, recurrent ulceration, re-hospitalisation, additional surgery, re-amputation and death, all within 12 months, and analysed the trajectories of the markers over time. Our primary outcome, DFO remission, was defined as wound healing within 12 months of follow-up without re-infection. We included 122 subjects; 65 patients (53·3%) had a combination of positive culture and histopathology. Factors associated with DFO remission (n = 46) were a lower white blood count (WBC) at admission (P = 0·006) and a higher glomerular filtration rate (GFR, P = 0·049). Factors associated with healing were a lower WBC (P = 0·004), a higher GFR (P = 0·01), longer wound duration before admission (P = 0·01), location of the ulcer on the great toe (P = 0·01) and higher glycated haemoglobin (P = 0·03). Logistic regression analysis demonstrated no associations between DFO remission and other variables collected. Trajectories of the inflammatory markers showed an association between stagnating values of ESR and CRP and poor clinical outcomes. In this study population, the trajectories of both ESR and CRP during 12 months follow-up suggest a predictive role of both inflammatory markers when monitoring treatment of DFO.

The value of inflammatory markers to diagnose and monitor diabetic foot osteomyelitis

In this study, we assessed the effectiveness of inflammatory markers to diagnose and monitor the treatment of osteomyelitis in the diabetic foot. We evaluated 35 consecutive patients admitted to our hospital with infected foot ulcers. Patients were divided in two groups based on the results of bone culture and histopathology: osteomyelitis and no osteomyelitis. The erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor alpha (TNFα), monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1 alpha (MIP1α) were measured at baseline after 3 and 6 weeks of standard therapy. PCT levels in the osteomyelitis group were significantly higher at baseline than in the group with no osteomyelitis (P = 0·049). There were no significant differences between the two groups in the levels of the other markers. CRP, ESR, PCT and IL-6 levels significantly declined in the group with osteomyelitis after starting therapy, while MCP-1 increased (P = 0·002). TNFα and MIP1α levels were below range in 80 out of 97 samples and therefore not reported. Our results suggest that PCT might be useful to distinguish osteomyelitis in infected foot ulcers. CRP, ESR, PCT and IL-6 are valuable when monitoring the effect of therapy.

What's new in the literature: an update of new research since the original WHS diabetic foot ulcer guidelines in 2006

The objective of the paper was to update the diabetic foot ulcer guidelines that were previously published in 2006. We performed a key word search using MEDLINE and Cochrane reviews for publication between January 2006 and January 2012. Articles that fit the inclusion criteria were reviewed and the previous guidelines were updated.

Osteomyelitis of the foot and ankle: diagnosis, epidemiology, and treatment

Osteomyelitis of the foot and ankle is a common, potentially devastating condition with diagnostic and treatment challenges. Understanding the epidemiology and pathogenesis of osteomyelitis can raise clinical suspicion and guide testing and treatments. History and physical examination, laboratory studies, vascular studies, histologic and microbiologic analyses, and various imaging modalities contribute to diagnosis and treatment. Treatment including empiric broad-spectrum antibiotics and surgery should take a multidisciplinary approach to optimize patient factors, ensure eradication of the infection, and restore function. Optimization of vascular status, soft tissues, limb biomechanics, and physiologic state of the patient must be considered to accelerate and ensure healing.

Diabetic foot ulcers: evaluation and management

Diabetic foot ulcers (DFUs) are a common complication of diabetes and present a significant health risk to patients, as well as impose a large economic burden. Evaluation for contributory factors that may impact general health or healing, such as hyperglycemia, peripheral artery disease, neuropathy, and nutritional status, is of the utmost importance. Management of DFUs requires involvement of a multidisciplinary team and a standardized approach to patient care. Standard therapy for DFUs includes offloading and debridement. Assessment and control of infection are critical, including determining the severity of the infection, which may drive therapeutic approaches. For recalcitrant ulcers, adjuvant therapies are used to hasten the healing process, and newer therapies are under investigation.

Diagnosing diabetic foot osteomyelitis: narrative review and a suggested 2-step score-based diagnostic pathway for clinicians

The diabetic foot infection remains a major cause of morbidity and mortality in many patients and remains a challenging diagnosis for most clinicians. Diagnosis is largely based on clinical signs supplemented by various imaging tests. Magnetic resonance imaging (MRI) is not readily available to many clinicians, and bone biopsy, which is the accepted criterion standard for diagnosis, is rarely performed routinely. This evidence-based review and the proposed diagnostic scoring pathway substratifies the current International Working Group on the Diabetes Foot guidelines for diagnosing diabetic foot osteomyelitis into a convenient 2-step diagnostic pathway for clinicians. This proposed diagnostic approach will need further validation prospectively, but it can serve as a useful diagnostic tool during the initial assessment and management of diabetic foot infections. A MEDLINE search of English-language articles on diabetic foot osteomyelitis published between 1986 and March 2014 was conducted. Additional articles were also identified through a search of references from the retrieved articles, published guidelines, systematic reviews, and meta-analyses.

Osteomyelitis or Charcot neuro-osteoarthropathy? Differentiating these disorders in diabetic patients with a foot problem

Both osteomyelitis and Charcot neuro-osteoarthropathy (CN) are potentially limb-threatening complications of diabetic neuropathy, but they require quite different treatments. Almost all bone infections in the diabetic foot originate from an infected foot ulcer while diabetic osteoarthropathy is a non-infectious process in which peripheral neuropathy plays the critical role. Differentiating between diabetic foot osteomyelitis and CN requires careful evaluation of the patient, including the medical history, physical examination, selected laboratory findings, and imaging studies. Based on available studies, we review the approaches to the diagnostic differentiation of osteomyelitis from CN of the foot in diabetic patients.

Osteomyelitis in the diabetic foot: diagnosis and management

Although osteomyelitis of the foot in diabetes remains common in specialist foot clinics across the world, the quality of published work to guide clinicians in the diagnosis and management is generally poor. Diagnosis should be based primarily on clinical signs supported by results of pathologic and radiologic investigations. Although the gold standard comes from the histologic and microbiological examination of bone, clinicians should be aware of the problems of sampling error. This lack of standardization of diagnostic criteria and of consensus on the choice of outcome measures poses further difficulties when seeking evidence to support management decisions. Experts have traditionally recommended surgical removal of infected bone but available evidence suggests that in many cases (excepting those in whom immediate surgery is required to save life or limb) a nonsurgical approach to management of osteomyelitis may be effective for many, if not most, patients with osteomyelitis of the diabetic foot. The benefits and limitations of both approaches need, however, to be established in prospective trials so that appropriate therapy can be offered to appropriate patients at the appropriate time, with the patients' views taken fully into account.

Diagnosing diabetic foot osteomyelitis in patients without signs of soft tissue infection by coupling hybrid 67Ga SPECT/CT with bedside percutaneous bone puncture

OBJECTIVE

Successful treatment of osteomyelitis is more likely with accurate diagnosis and identification of the causative pathogens. This typically requires obtaining a specimen of bone, usually by image-guided biopsy. We sought to develop a simpler bedside method for definitively diagnosing osteomyelitis.

RESEARCH DESIGN AND METHODS

Over 2 years, we enrolled consecutive patients presenting to our diabetic foot clinic with a foot ulcer and clinically suspected osteomyelitis but without soft tissue infection. Each underwent hybrid (67)Ga single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) imaging; those with a positive scan underwent bedside percutaneous bone puncture. Patients with a positive bone culture received culture-guided antibiotic therapy. Patients with negative (67)Ga SPECT/CT imaging or with positive imaging but negative bone culture were not treated with antibiotics. All patients were followed up for ≥ 1 year.

RESULTS

Among 55 patients who underwent (67)Ga SPECT/CT imaging, 13 had negative results and all of their foot ulcers resolved without antibiotic therapy. Among 42 with positive imaging, 2 were excluded (for recent antibiotic therapy) and 40 had bone punctures (3 punctured twice): 19 had negative results, 3 of which were likely false negatives, and 24 had positive results (all gram-positive cocci). At follow-up, 3 patients had died, 3 had undergone amputation, and 47 had no evidence of foot infection. The sensitivity and specificity of this combined method were 88.0 and 93.6%, respectively, and the positive and negative predictive values were 91.7 and 90.7%, respectively.

CONCLUSIONS

Coupling of (67)Ga SPECT/CT imaging and bedside percutaneous bone puncture appears to be accurate and safe for diagnosing diabetic foot osteomyelitis in patients without signs of soft tissue infection, obviating the need for antibiotic treatment in 55% of suspected cases.

The performance of serum inflammatory markers for the diagnosis and follow-up of patients with osteomyelitis

Serum inflammatory markers, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cells (WBC), and procalcitonin (PCT), have been used for the diagnosis of foot infections in patients with diabetes. However, little is known about their changes during treatment of patients with foot infections. The aim of this prospective study was to examine the performance of serum inflammatory markers for the diagnosis and follow-up of patients with osteomyelitis. A total of 61 patients (age 63.1 ± 7.0 years, 45 men and 16 women, 7 with type 1 and 54 with type 2 diabetes) with untreated foot infection (34 with soft-tissue infection and 27 with osteomyelitis) were recruited. Diagnosis of osteomyelitis was based on clinical examination and was confirmed by imaging studies (X-ray, scintigraphy, magnetic resonance imaging). Determination of the inflammatory markers was performed at baseline, after 1 week, after 3 weeks, and after 3 months of treatment. At baseline, the values of CRP, ESR, WBC, and PCT were significantly higher in patients with osteomyelitis than in those with soft-tissue infections. The sensitivity and specificity for the diagnosis of osteomyelitis of CRP (cutoff value >14 mg/L) were 0.85 and 0.83, of ESR (cutoff value >67 mm/h) 0.84 and 0.75, of WBC (cutoff value >14 × 10(9)/L) 0.75 and 0.79, and of PCT (cutoff value >0.30 ng/mL) 0.81 and 0.71, respectively. All values declined after initiation of treatment with antibiotics; the WBC, CRP, and PCT values returned to near-normal levels at day 7, whereas the values of ESR remained high until month 3 only in patients with bone infection. From the inflammatory markers, ESR is recommended to be used for the follow-up of patients with osteomyelitis.

Performance of the probe-to-bone test in a population suspected of having osteomyelitis of the foot in diabetes

BACKGROUND

We investigated the validity of probe-to-bone testing in the diagnosis of osteomyelitis in a selected subgroup of patients clinically suspected of having diabetic foot osteomyelitis.

METHODS

Between January 1, 2007, and December 31, 2008, inpatients and outpatients with a diabetic foot ulcer were prospectively evaluated, and those having a clinical diagnosis of foot infection and at least one of the osteomyelitis clinical suspicion criteria were consecutively included in this study.

RESULTS

Sixty-five patients met the inclusion criteria and were prospectively enrolled in the study. Forty-nine patients (75.4%) were hospitalized, and the remaining 16 (24.6%) were followed as outpatients. Osteomyelitis was diagnosed in 39 patients (60.0%). Probe-to-bone test results were positive in 30 patients (46.1%). The positive predictive value for the probe-to-bone test was fairly high (87%), but the negative predictive value was only 62%. The sensitivity and specificity of the test were 66% and 84%, respectively. White blood cell counts and mean C-reactive protein levels did not statistically significantly differ between groups. However, erythrocyte sedimentation rates greater than 70 mm/h reached statistical significance between groups. Wound area and depth were not found to be statistically significantly different between groups.

CONCLUSIONS

Positive probe-to-bone test results and erythrocyte sedimentation rates greater than 70 mm/h provide some support for the diagnosis of diabetic foot osteomyelitis, but it is not strong; magnetic resonance imaging or bone biopsy will probably be required in cases of doubt.

Severity of diabetic foot infection and rate of limb salvage

BACKGROUND

Foot infections are limb-threatening complications in patients with diabetes mellitus (DM), and proper classification of the severity of diabetic foot infection (DFI) is important in determining an effective antibiotic regimen, the need for hospitalization and surgery, and the risk of amputation. Our hypothesis was that patients with severe DFI would have a longer hospitalization than those with moderate DFI. The purposed of this study was 2-fold. The first purpose was to define DFI using readily available clinical information and objective parameters outlined by consensus statements. The second purpose of this study was to assess rates of amputation and limb salvage for hospitalized patients with DFI.

METHODS

The database of a single academic foot and ankle program was reviewed for patients who were hospitalized for a DFI from 2006 to 2011. Inpatient and outpatient electronic medical records identified 100 patients. Severe DFI was defined as having 2 or more objective findings of systemic toxicity and/or metabolic instability at the time of initial assessment.

RESULTS

The length of stay was significantly shorter for patients with a moderate infection than for those with a severe infection (median 5 days vs 8 days, P = .021). A nonsignificant trend was observed that indicated higher rates of limb salvage in patients with moderate infections compared with patients with severe infections (94% vs 80%, P = .081).

CONCLUSION

Patients with severe DFI had a median hospital stay that was 60% longer than that of patients with moderate DFI. In this sample, 55% of patients with a severe DFI required some type of amputation compared with 42% of patients with a moderate DFI.

LEVEL OF EVIDENCE

Level III, retrospective control cohort study.