Probing to bone in infected pedal ulcers. A clinical sign of underlying osteomyelitis in diabetic patients

Interobserver and Intraobserver Reproducibility of Plain X-Rays in the Diagnosis of Diabetic Foot Osteomyelitis

The purpose of this study was to analyze the interobserver and intraobserver variability in plain radiography in the diagnosis of diabetic foot osteomyelitis. A prospective observational study was performed from October 1, 2009, to July 31, 2011, on patients with diabetic foot ulcers, with clinically suspected osteomyelitis who were admitted to the Diabetic Foot Unit of the Complutense University of Madrid. Two professional groups examined 123 plain X-rays, each group comprising 3 different levels of clinical experience. To analyze intraobserver variability, 2 months later plain X-rays were reanalyzed by one of the clinical groups. When using only plain radiography for the diagnosis of osteomyelitis in the diabetic foot, low concordance rates were observed for clinicians with a similar level of experience: experienced clinicians ( K11AB = .35, P < .001), moderately experienced clinicians ( K22AB = .39, P < .001), and inexperienced clinicians ( K33AB = .40, P < .001). Intraobserver agreement was highest in experienced clinicians ( K11A = .75, P < .001), followed by moderately experienced clinicians ( K22A = .61, P < .001) and inexperienced clinicians ( K33A = .57, P < .001). Plain radiography for the diagnosis of diabetic foot osteomyelitis is operator dependent and shows low association strength, even among experienced clinicians, when interpreted in isolation without knowing the clinical characteristics of the lesion.

Magnetic resonance imaging of musculoskeletal infections: systematic diagnostic assessment and key points

Prompt diagnosis and treatment are essential in preventing the complications of musculoskeletal infection. In this context, imaging is often used to confirm clinically suspected diagnoses, define the extent of infection, and ensure appropriate management. Because of its superior soft-tissue contrast resolution, magnetic resonance imaging (MRI) is the modality of choice for evaluating musculoskeletal infections. This article describes the MRI features along the full spectrum of musculoskeletal infections and provides several illustrative case examples.

Risk factors for periprosthetic ankle joint infection: a case-control study

BACKGROUND

Periprosthetic ankle joint infection is a feared complication of total ankle arthroplasty because the implant fails in the majority of cases. However, risk factors for developing these infections are unknown.

METHODS

We aimed to determine risk factors for infection in a matched case-control study that included twenty-six patients with periprosthetic ankle joint infection and two control groups, each consisting of fifty-two patients.

RESULTS

The prevalence of periprosthetic ankle joint infection within our cohort was 4.7%. Four infections (15%) had a hematogenous origin and twenty-two (85%), an exogenous origin. Staphylococcus aureus was the most common pathogen, followed by coagulase-negative staphylococci. Preoperative predisposing factors associated with infection included prior surgery at the site of infection (odds ratio [OR] = 4.56, 95% confidence interval [CI] = 0.98 to 21.35, and OR = 4.78, 95% CI = 1.53 to 14.91, in comparison with the two control groups) and a low American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score (35.8 versus 49.8 and 47.6 in the two control groups, p ≤ 0.02). The mean duration of the index surgery was significantly longer in the case group than in both control groups (119 versus eighty-four and ninety-three minutes, p ≤ 0.02). After surgery, persistent wound dehiscence (OR = 15.38, 95% CI = 2.91 to 81.34, p = 0.01, in comparison with both control groups) and secondary wound drainage (OR = 7.00, 95% CI = 1.45 to 33.70, and OR = 5.31, 95% CI = 1.01 to 26.78, in comparison with the two control groups, p ≤ 0.04) were associated with the development of a periprosthetic ankle joint infection.

CONCLUSIONS

Patients at risk for periprosthetic ankle joint infection following total ankle arthroplasty include those with a history of surgery on the ankle, a low preoperative AOFAS hindfoot score, and a long operative time. Postoperatively, patients with a prolonged wound dehiscence or a secondary wound-healing problem are also at risk for infection.

Contemporary evaluation and management of the diabetic foot

Foot problems in patients with diabetes remain a major public health issue and are the commonest reason for hospitalization of patients with diabetes with prevalence as high as 25%. Ulcers are breaks in the dermal barrier with subsequent erosion of underlying subcutaneous tissue that may extend to muscle and bone, and superimposed infection is a frequent and costly complication. The pathophysiology of diabetic foot disease is multifactorial and includes neuropathy, infection, ischemia, and abnormal foot structure and biomechanics. Early recognition of the etiology of these foot lesions is essential for good functional outcome. Managing the diabetic foot is a complex clinical problem requiring a multidisciplinary collaboration of health care workers to achieve limb salvage. Adequate off-loading, frequent debridement, moist wound care, treatment of infection, and revascularization of ischemic limbs are the mainstays of therapy. Even when properly managed, some of the foot ulcers do not heal and are arrested in a state of chronic inflammation. These wounds can frequently benefit from various adjuvants, such as aggressive debridement, growth factors, bioactive skin equivalents, and negative pressure wound therapy. While these, increasingly expensive, therapies have shown promising results in clinical trials, the results have yet to be translated into widespread clinical practice leaving a huge scope for further research in this field.

2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections

Foot infections are a common and serious problem in persons with diabetes. Diabetic foot infections (DFIs) typically begin in a wound, most often a neuropathic ulceration. While all wounds are colonized with microorganisms, the presence of infection is defined by ≥2 classic findings of inflammation or purulence. Infections are then classified into mild (superficial and limited in size and depth), moderate (deeper or more extensive), or severe (accompanied by systemic signs or metabolic perturbations). This classification system, along with a vascular assessment, helps determine which patients should be hospitalized, which may require special imaging procedures or surgical interventions, and which will require amputation. Most DFIs are polymicrobial, with aerobic gram-positive cocci (GPC), and especially staphylococci, the most common causative organisms. Aerobic gram-negative bacilli are frequently copathogens in infections that are chronic or follow antibiotic treatment, and obligate anaerobes may be copathogens in ischemic or necrotic wounds. Wounds without evidence of soft tissue or bone infection do not require antibiotic therapy. For infected wounds, obtain a post-debridement specimen (preferably of tissue) for aerobic and anaerobic culture. Empiric antibiotic therapy can be narrowly targeted at GPC in many acutely infected patients, but those at risk for infection with antibiotic-resistant organisms or with chronic, previously treated, or severe infections usually require broader spectrum regimens. Imaging is helpful in most DFIs; plain radiographs may be sufficient, but magnetic resonance imaging is far more sensitive and specific. Osteomyelitis occurs in many diabetic patients with a foot wound and can be difficult to diagnose (optimally defined by bone culture and histology) and treat (often requiring surgical debridement or resection, and/or prolonged antibiotic therapy). Most DFIs require some surgical intervention, ranging from minor (debridement) to major (resection, amputation). Wounds must also be properly dressed and off-loaded of pressure, and patients need regular follow-up. An ischemic foot may require revascularization, and some nonresponding patients may benefit from selected adjunctive measures. Employing multidisciplinary foot teams improves outcomes. Clinicians and healthcare organizations should attempt to monitor, and thereby improve, their outcomes and processes in caring for DFIs.

Prevalence of diabetic neuropathy in patients undergoing foot and ankle surgery

INTRODUCTION

The aim of this prospective study was to determine the prevalence of neuropathy in diabetic patients undergoing foot and ankle surgery. It was hypothesized that the prevalence of diabetic neuropathy is higher among patients who undergo foot and ankle surgery compared with historical rates of neuropathy in diabetic patients in general.

METHODS

During a consecutive 42-month period, patient data were prospectively entered for 1859 consecutive patients undergoing foot and ankle surgery. Among the subjects, 394 had been previously diagnosed with diabetes mellitus (DM), and the remaining 1465 did not have DM.

RESULTS

The prevalence of neuropathy in patients with and without DM was 77.2% (304 of 394 patients) and 11.7% (172 of 1465 patients), respectively. Patients with diabetic neuropathy were older, had poorer glycemic control, had higher serum creatinine levels, and reported more significant tobacco use than diabetic patients without neuropathy.

CONCLUSION

Nearly 80% of diabetic patients undergoing foot and ankle surgery at a large academic medical center had diabetic neuropathy. Preoperative recognition of this morbid complication of DM is important to appropriately stratify those diabetic patients into a high-risk category.

Expert opinion on the management of infections in the diabetic foot

This update of the International Working Group on the Diabetic Foot incorporates some information from a related review of diabetic foot osteomyelitis (DFO) and a systematic review of the management of infection of the diabetic foot. The pathophysiology of these infections is now well understood, and there is a validated system for classifying the severity of infections based on their clinical findings. Diagnosing osteomyelitis remains difficult, but several recent publications have clarified the role of clinical, laboratory and imaging tests. Magnetic resonance imaging has emerged as the most accurate means of diagnosing bone infection, but bone biopsy for culture and histopathology remains the criterion standard. Determining the organisms responsible for a diabetic foot infection via culture of appropriately collected tissue specimens enables clinicians to make optimal antibiotic choices based on culture and sensitivity results. In addition to culture-directed antibiotic therapy, most infections require some surgical intervention, ranging from minor debridement to major resection, amputation or revascularization. Clinicians must also provide proper wound care to ensure healing of the wound. Various adjunctive therapies may benefit some patients, but the data supporting them are weak. If properly treated, most diabetic foot infections can be cured. Providers practising in developing countries, and their patients, face especially challenging situations.

Seminar Review: A Review of the Basis of Surgical Treatment of Diabetic Foot Infections

Infection is an extremely challenging complication of foot ulcers in patients with diabetes. Surgery as part of a multidisciplinary approach is key in the management of many types of diabetic foot infections (DFIs). Unfortunately, the surgical treatment of DFIs is based more on clinical judgment and less on structured evidence, which leaves unresolved doubts. The clinical presentation of DFIs is varied. This review examines the basis of nonvascular surgical treatment of DFIs, emphasizing the importance of the anatomic concepts of the foot, the variety of its clinical presentations, and the concepts of timing surgery. Recent evidence and case reports based on the author’s experience are presented in 2 parts. The first part examines clinical presentation of infections, whereas the second part deals with imaging, foot anatomy, and some case reports.

Histology versus microbiology for accuracy in identification of osteomyelitis in the diabetic foot

It is important to accurately diagnose osteomyelitis, and bone biopsy is currently considered by many to be the gold standard diagnostic test for its identification. Microbiologic studies, namely culture and sensitivity tests, are also used to identify osteomyelitis. To our knowledge, no published reports exist that compare the diagnostic characteristics of bone biopsy to microbiology with regard to making the diagnosis of osteomyelitis. For these reasons, we undertook a matched case control study to test the null hypothesis that claimed there is no difference between histology and microbiology with regard to making the diagnosis of pedal osteomyelitis in diabetic patients. The sample population consisted of consecutive diabetic patients from a tertiary care hospital who were surgically treated for foot infection with suspected osteomyelitis. Each bone specimen was hemisected, and one half sent for microbiologic testing and the other half sent for histopathologic inspection. McNemar's test for correlated proportions was used to identify whether or not a statistically significant difference existed between the diagnostic methods. A total of 44 specimens were analyzed, and our results showed that a positive microbiologic and negative histologic result was just as likely as a negative microbiologic and positive histologic result (P > .05). In conclusion, based on the results of this investigation, microbiologic testing performed as well as did histopathologic testing when it came to identifying the presence of pedal osteomyelitis in the diabetic foot.

Role of bone biopsy specimen culture in the management of diabetic foot osteomyelitis

INTRODUCTION

There has been increasing evidence in favor of conservative management of diabetic foot osteomyelitis which requires targeted antibiotic therapy to the causative pathogen. But the method of reliable microbiological isolation is controversial.

AIMS AND OBJECTIVES

To study the concordance of superficial swab culture with bone biopsy specimen culture in patients with diabetic foot osteomyelitis.

MATERIALS AND METHODS

A prospective study was conducted from July 2008 to July 2010. All consecutive patients with suspected diabetic foot osteomyelitis were included in the study. Superficial swab and Percutaneous bone biopsy specimens were obtained for culture. The culture results in these two groups were compared for concordance.

RESULTS

A total of 144 patients were included in the study. 134 cases of bone biopsy specimen and 140 cases of superficial swab showed positive culture results. Mean number of isolate per sample was similar. Staphylococcus aureus was the commonest organism grown in both cultures. The bone pathogen was identified in the corresponding swab culture in only 55 cases (38.2%). Staphylococcus aureus had the highest concordance percentage of 46.5% which was not statistically significant.

CONCLUSION

Superficial swab culture may not be accurate in identifying all the organisms causing diabetic foot osteomyelitis. Bone biopsy specimen taken simultaneously would increase the accuracy of detecting the bacterial isolate.

Surgical management of a diabetic calcaneal ulceration and osteomyelitis with a partial calcanectomy and a sural neurofasciocutaneous flap

The treatment of calcaneal osteomyelitis in diabetic patients poses a great challenge to the treating physician and surgeon. The use of a distally based sural neurofasciocutaneous flap after an aggressive debridement of non-viable and poorly vascularized tissue and bone that is combined with a thorough antibiotic regimen provides a great technique for adequate soft tissue coverage of the heel. In this case report, the authors describe the aforementioned flap as a versatile alternative to the use of local or distant muscle flaps for diabetic patients with calcaneal osteomyelitis and concomitant large wounds.

Validating the probe-to-bone test and other tests for diagnosing chronic osteomyelitis in the diabetic foot

OBJECTIVE

To compare the diagnostic characteristics of tests used for a prompt diagnosis of chronic osteomyelitis in the diabetic foot, using bone histology as the criterion standard. The tests assessed were probe-to-bone (PTB), clinical signs of infection, radiography signs of osteomyelitis, and ulcer specimen culture.

RESEARCH DESIGN AND METHODS

A prospective study was performed on patients with foot ulcers referred to our diabetic foot clinic. Ulcer infection was diagnosed by recording clinical signs of infection and taking specimens for culture. The presumptive diagnosis of osteomyelitis was based on these results and the findings of a plain X-ray and PTB test. All patients with a clinical suspicion of bone infection were subjected to surgical treatment of the affected bone. During surgery, bone specimens were obtained for a histological diagnosis of osteomyelitis.

RESULTS

Over 2.5 years, 210 foot lesions were consecutively examined and 132 of these wounds with clinical suspicion of infection selected as the study sample. Of these, 105 (79.5%) lesions were diagnosed as osteomyelitis. Among the tests compared, the best results were yielded by the PTB test including an efficiency of 94%, sensitivity of 98%, specificity of 78%, positive predictive value of 95%, and negative predictive value of 91% (P < 0.001, κ 0.803); the positive likelihood ratio was 4.41, and the negative likelihood ratio was 0.02 (95% CI).

CONCLUSIONS

In our outpatient population with a high prevalence of osteomyelitis, the PTB test was of greatest diagnostic value, especially for neuropathic ulcers, and proved to be efficient for detecting osteomyelitis in the diabetic foot.

Surgery for diabetic foot infections

Diabetes mellitus is a common disease in the world today and its prevalence is increasing. Foot and ankle complications, including infection, are the most common reason for hospital admission in patients with diabetes mellitus in the United States and are commonly encountered by the foot and ankle surgeon. Thorough clinical examination with appropriate use of adjunctive laboratory and imaging studies can allow for early diagnosis and treatment, which can improve patient outcomes. Mild infections can often be treated on an outpatient basis with oral antibiotics and local debridement, whereas more severe infections require hospitalization, intravenous antibiotics, and surgical debridement to fully eradicate the infection. Despite proper treatment, amputation is still common in diabetics.

Clinical significance of the isolation of Staphylococcus epidermidis from bone biopsy in diabetic foot osteomyelitis

Introduction

Coagulase-negative staphylococci are considered as microorganisms with little virulence and usually as contaminants. In order to establish the role of Staphylococcus epidermidis as a pathogen in diabetic foot osteomyelitis, in addition to the isolation of the sole bacterium from the bone it will be necessary to demonstrate the histopathological changes caused by the infection.

Methods

A consecutive series of 222 diabetic patients with foot osteomyelitis treated surgically in the Diabetic Foot Unit at La Paloma Hospital (Las Palmas de Gran Canaria, Canary Islands, Spain) between 1 October 2002 and 31 October 2008. From the entire series including 213 bone cultures with 241 isolated organisms, we have analyzed only the 139 cases where Staphylococci were found. We analyzed several variables between the two groups: Staphylococcus aureus versus Staphylococcus epidermidis.

Results

Of the 134 patients included in this study, Staphlylococcus epidermidis was found as the sole bacterium isolated in 11 cases and accompanied by other bacteria in 12 cases. Staphlylococcus aureus was found as the sole bacterium isolated in 72 cases and accompanied by other bacteria in 39 cases. Histopathological changes were found in the cases of osteomyelitis where Staphylococcus epidermidis was the sole bacterium isolated. Acute osteomyelitis was found to a lesser extent when Staphylococcus epidermidis was the sole bacterium isolated but without significant differences with the cases where Staphylococcus aureus was the sole bacterium isolated.

Conclusion

Staphylococcus epidermidis should be considered as a real pathogen, not only a contaminant, in diabetic patients with foot osteomyelitis when the bacterium is isolated from the bone. No differences in the outcomes of surgical treatment have been found with cases which Staphlylococcus aureus was isolated.

Management of calcaneal osteomyelitis

Calcaneal osteomyelitis is a complicated clinical scenario, which is often very difficult to treat. It can occur in individuals of any age who are injured or immunocompromised, and once diagnosed, aggressive management should be initiated. Treatment ranges from antibiotics alone to radical debridement or amputation. If there is a delay in both diagnosis and treatment, calcaneal osteomyelitis can be limb threatening or even life threatening.

Review Paper: Basic Concepts to Novel Therapies: A Review of the Diabetic Foot

Diabetes mellitus is a global epidemic. Peripheral neuropathy and peripheral vascular disease are complications of diabetes mellitus and the primary causative factors for foot ulceration. Foot ulceration is the leading cause of hospitalization in people with diabetes mellitus. The burden of foot ulceration on health care systems and individual patients is immense. Despite conventional treatment, there persists a high incidence of amputation. A multidisciplinary approach is required to prevent ulcers. This review describes the etiology and risk factors for diabetic foot ulceration and a system for evaluating the diabetic foot. The assessment of neuropathy and the grading of foot ulcers are critically examined. This is important to allow for standardization in clinical trials. The management of diabetic foot syndrome is reviewed. The treatments to ensure vascular supply to the lower limb and control of infection as well as novel therapies, which are becoming available to treat nonhealing, “no-option” diabetic ulcers, are discussed.

Review Papers: Current Techniques to Detect Foot Infection in the Diabetic Patient

Diabetic foot infections can be a challenge to diagnose, especially when osteomyelitis is in question. Evaluation of infection should involve a thorough examination of the extremity for clinical signs of infection along with appropriate laboratory and imaging studies. Laboratory markers of inflammation such as peripheral leukocyte count, erythrocyte sedimentation rate, C-reactive protein, and procalcitonin may provide useful information when diagnosing soft tissue and bone infection. However, laboratory markers alone should not be used to diagnose a diabetic foot infection as they are non-specific in nature. Imaging studies may also provide valuable clues regarding the presence of infection. Plain radiographs are a good initial screening tool as they are both inexpensive and easily accessible. However, their sensitivity in diagnosing osteomyelitis is poor. Thus, more advanced imaging such as radionuclide imaging and magnetic resonance imaging are warranted when osteomyelitis is suspected. Magnetic resonance imaging is presently considered the gold standard in diagnosing osteomyelitis, despite its wide variation in reported sensitivity and specificity. However, the significant cost of magnetic resonance imaging prevents its use as a screening tool. Collection of reliable microbiologic data is critical in making a diagnosis as well as for treatment of infection, especially when osteomyelitis is concerned. Deep swabs and transcutaneous bone biopsy are considered the ideal methods of obtaining the necessary information. Finally, monitoring treatment should also be performed with an eye towards both laboratory data and the clinical exam.

Osteomyelitis of the iliac crest: a rare complication following perforated appendicitis

BACKGROUND

Appendicitis is a common surgical emergency with numerous postoperative infective complications. We report an unusual case of iliac crest osteomyelitis as a late complication following emergency appendectomy for perforated gangrenous appendicitis.

METHODS

Review of the pertinent English language literature.

RESULTS

To the best of our knowledge, this is the first report in the English literature to describe iliac crest osteomyelitis as an infective complication of perforated gangrenous appendicitis. The diagnosis was made with the aid of magnetic resonance imaging and radioisotope bone scans. The complication was treated successfully with broad-spectrum intravenous antibiotics and physiotherapy.

CONCLUSION

Iliac crest osteomyelitis is indeed a rare complication of appendicitis. A heightened awareness and better understanding of this complication would necessitate early diagnosis and treatment.

Diabetic foot infections: a team-oriented review of medical and surgical management

As the domestic and international incidence of diabetes and metabolic syndrome continues to rise, health care providers need to continue improving management of the long-term complications of the disease. Emergency department visits and hospital admissions for diabetic foot infections are increasingly commonplace, and a like-minded multidisciplinary team approach is needed to optimize patient care. Early recognition of severe infections, medical stabilization, appropriate antibiotic selection, early surgical intervention, and strategic plans for delayed reconstruction are crucial components of managing diabetic foot infections. The authors review initial medical and surgical management and staged surgical reconstruction of diabetic foot infections in the inpatient setting.

Necrotizing soft-tissue infections in the feet of patients with diabetes: outcome of surgical treatment and factors associated with limb loss and mortality

The aim of this study was to analyze the outcomes of treatment of necrotizing soft-tissue infections (NSTIs) in the feet of diabetic patients and to determine factors associated with limb salvage and mortality. A retrospective study of a consecutive series of 145 diabetic patients suffering from NSTIs treated in the Diabetic Foot Unit, La Paloma Hospital was done. NSTIs were classified as necrotizing cellulitis if it involved the subcutaneous tissue and the skin, as necrotizing fasciitis if it involved the deep fascia, and as myonecrosis in those cases where muscular necrosis was present. In the necrotizing cellulitis group (n = 109), 8 (7.3%) major amputations were performed. In the necrotizing fasciitis group (n = 25), 13 (52%) major amputations were undertaken. In the myonecrosis group (n = 11), 6 (54.5%) major amputations were performed. Predictive variables related to limb loss were fasciitis (OR = 20, 95% CI = 3.2-122.1) and myonecrosis (OR = 53.2, 95% CI = 5.1-552.4). Predictive variables of mortality were age >75 years (OR = 10.3, 95% CI = 1.9-53.6) and creatinine values >132.6 micromol/L (OR = 5.8, 95% CI = 1.1-30.2). NSTIs of the foot are an important cause of morbidity and mortality in diabetic patients.When fascia and/or muscle are involved, there are significant risks of major amputation.

Limb salvage in Charcot foot and ankle osteomyelitis: combined use single stage/double stage of arthrodesis and external fixation

BACKGROUND

Charcot neuroarthropathy of the foot/ankle is a devastating complication of diabetes. Along with neuroarthropathy, osteomyelitis can occur which can result in amputation. This prospective study evaluated a limb salvage procedure as an alternative to amputation through surgical treatment of osteomyelitis of the midfoot or the ankle and stabilization with external fixation.

MATERIALS AND METHODS

Forty-five patients with Charcot arthropathy and osteomyelitis underwent debridement and attempted fusion with an external fixator. Chart and radiograph review was performed to assess the success of the fusion and eradication of infection.

RESULTS

Out of 45 patients, 39 patients healed using emergent surgery to drain an acute manifestation of the infection while maintaining the fixation for an average of 25.7 weeks. Two patients were treated with intramedullary nail in a subsequent surgical procedure. In four patients, the infection could not be controlled, therefore a major amputation was carried out.

CONCLUSION

For select patients, external fixation proved to be a reasonable alternative to below-knee amputation.

Conservative management of diabetic forefoot ulceration complicated by underlying osteomyelitis: the benefits of magnetic resonance imaging

AIMS

To assess efficacy of conservative management of neuropathic forefoot ulcers with underlying osteomyelitis in subjects with diabetes when magnetic resonance imaging (MRI) is used to confirm or establish diagnosis and to guide antibiotic duration.

METHODS

A retrospective cohort study over 6 years assessing rates of ulcer healing, relapse and amputation. Antibiotics were continued for 3-month cycles with interval MRI: if the lesion had healed and bone signal change resolved or improved, antibiotics were discontinued; if the lesion had not healed or there was no difference in bone signal change, antibiotics were continued for a further 3-month cycle; clinical or radiological deterioration resulted in endoluminal or open vascular surgical intervention where appropriate, or digital or more proximal amputation.

RESULTS

There were 53 episodes in 47 subjects (mean +/- sd age 62 +/- 13 years, duration of diabetes 19 +/- 13 years, glycated haemoglobin 8.4 +/- 1.6%; six with Type 1 diabetes and seven with end-stage renal failure). Successful healing without relapse was achieved in 40 episodes (75%) [median (range) duration of antibiotics 6 (3-12) months and follow-up post-cessation of antibiotics 15 (3-58) months]. Relapse occurred in six episodes (13%) at 31 (2-38) months post-cessation of antibiotics. There were one major (2%) and eight minor (15%) amputations. Five subjects have died (11%), all without foot ulcers.

CONCLUSIONS

High rates of healing and low rates of amputation were achieved. The use of MRI was associated with long courses of antibiotics, but particularly low relapse rate.

Surgical aspects of the diabetic foot

A comprehensive review of the literature relating to the pathology and management of the diabetic foot is presented. This should provide a guide for the treatment of ulcers, Charcot neuro-arthropathy and fractures involving the foot and ankle in diabetic patients.

Diabetic foot osteomyelitis: a progress report on diagnosis and a systematic review of treatment

The International Working Group on the Diabetic Foot appointed an expert panel to provide evidence-based guidance on the management of osteomyelitis in the diabetic foot. Initially, the panel formulated a consensus scheme for the diagnosis of diabetic foot osteomyelitis (DFO) for research purposes, and undertook a systematic review of the evidence relating to treatment. The consensus diagnostic scheme was based on expert opinion; the systematic review was based on a search for reports of the effectiveness of treatment for DFO published prior to December 2006. The panel reached consensus on a proposed scheme that assesses the probability of DFO, based on clinical findings and the results of imaging and laboratory investigations. The literature review identified 1168 papers, 19 of which fulfilled criteria for detailed data extraction. No significant differences in outcome were associated with any particular treatment strategy. There was no evidence that surgical debridement of the infected bone is routinely necessary. Culture and sensitivity of isolates from bone biopsy may assist in selecting properly targeted antibiotic regimens, but empirical regimens should include agents active against staphylococci, administered either intravenously or orally (with a highly bioavailable agent). There are no data to support the superiority of any particular route of delivery of systemic antibiotics or to inform the optimal duration of antibiotic therapy. No available evidence supports the use of any adjunctive therapies, such as hyperbaric oxygen, granulocyte-colony stimulating factor or larvae. We have proposed a scheme for diagnosing DFO for research purposes. Data to inform treatment choices in DFO are limited, and further research is urgently needed.

Potential role of FDG PET in the setting of diabetic neuro-osteoarthropathy: can it differentiate uncomplicated Charcot's neuroarthropathy from osteomyelitis and soft-tissue infection?

BACKGROUND

This paper is based on the results from an ongoing prospective trial designed to investigate the usefulness of FDG PET in the complicated diabetic foot.

AIM

To investigate the potential utility of FDG PET imaging in the setting of acute neuropathic osteoarthropathy (Charcot's foot).

PATIENTS AND METHODS

A total of 63 patients, in four groups, were evaluated. The groups were: (A) 17 patients with a clinical diagnosis of Charcot's neuroarthropathy (11 men, six women; mean age: 59.4+/-8.6 years); (B) 21 patients with uncomplicated diabetic foot (16 men, five women; mean age: 63+/-10 years); (C) 20 non-diabetic patients with normal lower extremities (12 men, eight women; mean age 54+/-19 years); and (D) five patients with proven osteomyelitis secondary to complicated diabetic foot (three men, two women; mean age: 61.2+/-13.9 years). Five patients in group A had foot ulcer and intermediate to high degree of suspicion for superimposed osteomyelitis. Each subject underwent FDG PET imaging of the lower extremities in addition to MRI and the findings were compared with the final diagnostic outcome based on histopathology and clinical follow-up. The images were examined visually for focal abnormalities. Regions of interest were assigned to the sites of abnormal FDG uptake for calculating maximum standardized uptake value (SUVmax). Two important clinical decision-making issues were explored: (1) whether FDG PET shows a definitive uptake pattern in Charcot's neuroarthropathy and if so whether that could be utilized to differentiate it from other complicated forms of diabetic foot like osteomyelitis and cellulitis, which is frequently a diagnostic challenge in this clinical setting; and (2) how accurate FDG PET is in detection soft tissue infection in patients with Charcot's foot. These issues were examined by utilizing FDG PET findings along with MRI results in the same patient.

RESULTS

We observed a low degree of diffuse FDG uptake in the Charcot's joints. This was clearly distinguishable from the normal joints. The SUVmax in the Charcot's lesions varied from 0.7 to 2.4 (mean, 1.3+/-0.4) while those of midfoot of the normal control subjects and the uncomplicated diabetic foot ranged from 0.2 to 0.7 (mean 0.42+/-0.12) and from 0.2 to 0.8 (mean 0.5+/-0.16), respectively. The only patient with Charcot's foot with superimposed osteomyelitis had an SUVmax of 6.5. The SUVmax of the sites of osteomyelitis as a complication of diabetic foot was 2.9-6.2 (mean: 4.38+/-1.39). Unifactorial analysis of variance test yielded a statistical significance in the SUVmax between the four groups (P<0.01). The SUVmax between the normal control groups and the uncomplicated diabetic foot was not statistically significant by the Student's t-test (P>0.05). In the setting of concomitant foot ulcer FDG PET accurately ruled out osteomyelitis. Overall sensitivity and accuracy of FDG PET in the diagnosis of Charcot's foot was 100 and 93.8%, respectively; and for MRI were 76.9 and 75%, respectively. FDG PET showed foci of abnormally enhanced uptake in the soft tissue which was suggestive of inflammation in seven cases (43.75%) which were proven pathologically to be secondary to infection. In only two of these cases the features of soft tissue infection were noted on the magnetic resonance images.

CONCLUSION

The results support a valuable role of FDG PET in the setting of Charcot's neuroarthropathy by reliably differentiating it from osteomyelitis both in general and when foot ulcer is present.

Surgical management of diabetic foot infections and osteomyelitis

Foot ulceration and subsequent infection are a major complication of diabetes mellitus. Without proper diagnosis and treatment, these infections often lead to amputation. A multidisciplinary team approach is essential to maximize outcomes in the attempt to limit amputation and decrease patient morbidity. Mild to moderate diabetic foot infections often respond favorably to local wound care, offloading, and antibiotic therapy. When conservative measures fail or when faced with limb- or life-threatening infection, surgical intervention, whether it be incision and drainage or possible amputation, is warranted. The authors review underlying pathophysiology of diabetic foot infections and an evidenced-based approach to surgical management, with additional emphasis on treatment of osteomyelitis.

A new method of monitoring osteomyelitis

Chronic infections of bone such as osteomyelitis are frequent events, especially in immunocompromised or diabetic patients, and costly on a national level. Incorrect treatment or delayed diagnosis may lead to loss of the affected extremity or mandible. The aim of this study was to assess the possible value of urinary lysylpyridinoline (LP) and hydroxylysylpyridinoline (HP) concentrations in the monitoring of mandibular osteomyelitis. Patients were assigned to the following groups: group 1 (n=85), control; group 2a (n=38), patients with active disease; group 2b (n=25), patients of group 2a 6 months after successful treatment; group 2c (n=7), patients of group 2a with ongoing osteomyelitis 6 months after treatment. The range and upper limit of normal values (HP(max) and LP(max)) were determined in group 1. Levels of LP and HP were measured by high-performance liquid chromatography and fluorescence detection. There was a significant decrease (mean 45.43% for HP and 32.12% for LP) in samples of group 2b compared to 2a (P<0.001 for HP and LP). There was a significant increase in HP values in samples from group 2c compared to 2a (P=0.018). The urinary concentrations of HP and LP appear to act as a marker of disease activity, with a decrease reflecting treatment success and an increase or stable values indicating persistent disease. An inexpensive tool (US$5 per analysis) for the monitoring of osteomyelitis is described.

An infectious disease update on antibiotics: emerging resistance

Podiatric physicians often encounter infectious processes in the lower extremity in inpatient and outpatient settings. Bacterial resistance to antibiotics is a growing concern for clinicians treating these infections, especially in complex patients who have immune compromise such as diabetes. Although a number of antibiotic options are available for the treatment of lower-extremity soft tissue and bone infections, a careful examination of bacterial susceptibilities, drug resistance, and treatment efficacy can result in better patient care and limb salvage.

Clinical management of diabetic foot infection: diagnostics, therapeutics and the future

Diabetic foot infection accounts for a substantial global burden of morbidity, psychosocial disruption and economic cost. Recommendations for best practice are continuously evolving in parallel with improvements in imaging modalities, development and clinical use of new antimicrobial agents and data surrounding novel adjunctive strategies. We discuss this complex group of infections with a particular emphasis on medical management of osteomyelitis, while also highlighting the importance of a broad multidisciplinary approach to eradicating infection.