High-Risk Patients with Infected Puncture Wounds and Appropriate Tetanus Prophylaxis.

BACKGROUND: We sought to evaluate clinicians' compliance with national guidelines for tetanus vaccination prophylaxis in patients with high-risk feet. METHODS: We retrospectively evaluated 114 consecutive patients between June 1, 2011, and March 31, 2019, who presented to the emergency department with a foot infection resulting from a puncture injury. Eighty-three patients had diabetes mellitus and 31 patients did not have diabetes mellitus. Electronic medical records were used to collect a broad range of study data on patient demographics, medical history, tetanus immunization history and tetanus status on presentation to the emergency department, peripheral arterial disease, sensory neuropathy, laboratory values, and clinical/surgical outcomes. RESULTS: Of the 114 patients who presented to the emergency department with a puncture wound, 53 (46.5%) did not have up-to-date tetanus immunization. Of those patients, 79.2% received a tetanus-containing vaccine booster, 3.8% received intramuscular tetanus immunoglobulin, 3.8% received both a tetanus-containing vaccine booster and tetanus immunoglobulins, and 20.8% received no form of tetanus prophylaxis. Comparing data between patients with and without diabetes mellitus, there were no statistically significant differences in tetanus prophylaxis. CONCLUSIONS: Guidelines for tetanus prophylaxis among high-risk podiatric medical patients in this study center are not followed in all patients. Patients with diabetes mellitus are at high risk for exposure to tetanus; therefore, we recommend that physicians take a detailed tetanus immunization history and vaccinate patients if the tetanus history is unclear.

Incidence and Recovery of Acute Kidney Injury in Diabetic and Nondiabetic Patients with Foot Infections.

BACKGROUND: The aim of this study was to evaluate the incidence and recovery of acute kidney injury (AKI) in patients admitted to the hospital with and without diabetes mellitus (DM) with foot infections. METHODS: We retrospectively reviewed 294 patients with DM and 88 without DM admitted to the hospital with foot infections. The Kidney Disease: Improving Global Outcomes guidelines were used to define AKI. Recovery was divided into three categories: full, partial, and no recovery within 90 days of the index AKI. RESULTS: The AKI incidence was 3.0 times higher in patients with DM (DM 48.5% versus no DM 23.9%; 95% confidence interval [CI], 1.74-5.19; P < .01). Acute kidney injury incidence was similar at each stage in people with and without DM (stage 1, DM 58.1% versus no DM 47.6%; stage 2, DM 23.3% versus no DM 33.3%, and stage 3, DM 18.6% versus no DM 19.1%). Twenty-nine patients with diabetes had a second AKI event and four had a third event. In patients without DM, one patient had a second AKI. Cumulative AKI incidence was 4.7 times higher in people with DM (DM 60.9% versus no DM 25.0%; 95% CI, 2.72-8.03; P < .01). Patients with diabetes progressed to chronic kidney disease or in chronic kidney disease stage 39.4% of the time. Patients without diabetes progressed 16.7% of the time, but this trend was not significant (P = .07). Complete recovery was 3.8 times more likely in patients without diabetes (95% CI, 1.26-11.16; P = .02). CONCLUSIONS: Acute kidney injury incidence is higher in patients with diabetes, and complete recovery after an AKI is less likely compared to patients without diabetes.

A Comparison of Pathogens in Skin and Soft-Tissue Infections and Pedal Osteomyelitis in Puncture Wound Injuries Affecting the Foot.

BACKGROUND: To compare pathogens involved in skin and soft-tissue infections (SSTIs) and pedal osteomyelitis (OM) in patients with and without diabetes with puncture wounds to the foot. METHODS: We evaluated 113 consecutive patients between June 1, 2011, and March 31, 2019, with foot infection (SSTIs and OM) from a puncture injury sustained to the foot. Eighty-three patients had diabetes and 30 did not. We evaluated the bacterial pathogens in patients with SSTIs and pedal OM. RESULTS: Polymicrobial infections were more common in patients with diabetes mellitus (83.1% versus 53.3%; P = .001). The most common pathogen for SSTIs and OM in patients with diabetes was Staphylococcus aureus (SSTIs, 50.7%; OM, 32.3%), whereas in patients without diabetes it was Pseudomonas (25%) for SSTIs. Anaerobes (9.4%) and fungal infection (3.1%) were uncommon. Pseudomonas aeruginosa was identified in only 5.8% of people with diabetes. CONCLUSIONS: The most common bacterial pathogen in both SSTIs and pedal OM was S aureus in patients with diabetes. Pseudomonas species was the most common pathogen in people without diabetes with SSTIs.

Effect of Sensory Neuropathy on the Predictive Value of Inflammatory Biomarkers for Osteomyelitis in Diabetic and Nondiabetic Patients with Foot Infections.

OBJECTIVE: To investigate the predictive value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in persons with and without diabetes with osteomyelitis (OM). METHODS: We evaluated 455 patients in a retrospective cohort study of patients admitted to the hospital with diabetic foot OM (n = 177), diabetic foot soft-tissue infections (STIs) (n = 176), nondiabetic OM (n = 51), and nondiabetic STIs (n = 51). Infection diagnosis was determined through bone culture, histopathologic examination for OM, and/or imaging (magnetic resonance imaging/single-photon emission computed tomography) for STI. The optimal cutoff values of ESR and CRP in predicting OM were determined by receiver operating characteristic curve analysis. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined through contingency tables. RESULTS: In persons without diabetes with STI or OM, the mean ESR and CRP differences were 10.0 mm/h and 2.6 mg/dL, respectively. In contrast, persons with diabetes had higher levels of each: 24.8 mm/h and 6.8 mg/dL, respectively. As a result, ESR and CRP predicted OM better in patients with diabetes. However, when patients were stratified by neuropathy status, ESR remained predictive of OM in diabetic patients with neuropathy (75% sensitivity, 58% specificity) but not in diabetic patients without neuropathy (50% sensitivity, 44% specificity). Also, CRP remained predictive irrespective of neuropathy status. A similar trend was observed in patients without diabetes. CONCLUSIONS: Previous studies have reported that ESR and CRP are predictive of OM. However, this study suggests that neuropathy influences the predictive value of inflammatory biomarkers. The underlying mechanisms require further study.

Conservative Offloading.

The etiology of ulcerations in diabetes mellitus is associated with the presence of peripheral sensory neuropathy and repetitive trauma due to normal walking activities to areas on the foot that are subject to moderate or high pressures and shear. The combination of loss of protective sensation, deformity, and repetitive trauma is the perfect storm for ulcer development. Once an ulcer is developed, the most important part of the healing process is offloading the ulcer site. Offloading is the mainstay of healing neuropathic ulcers.

Current concepts in curative surgery for diabetic forefoot ulcers.

Forefoot ulcerations in patients with diabetes are quite common. Underlying mechanical deformities of the foot in combination with neuropathy are the most important risk factors for ulcer development and adequate offloading is the mainstay of management. Most ulcers heal with local wound care, adequate blood supply, and pressure relief. If a foot deformity cannot be accommodated, ulcers will not heal or may recur. In this case, surgical correction of deformity is necessary. This paper reviews the most common procedures supported by medical evidence to heal neuropathic forefoot ulcers.

Does the Start of Dialysis Initiate a Period of Increased Risk of Ulceration or Amputation?

BACKGROUND: Dialysis therapy is associated with an increased incidence of lower-extremity wounds and amputations. We compared the incidence of foot ulcers and amputations before and after the start of dialysis. METHODS: We evaluated 150 consecutive diabetic patients receiving dialysis and compared the incidence of foot complications 30 months before and after initiation of hemodialysis. We used claims data for diabetes, ulceration, and dialysis and abstracted medical records to verify diagnoses and dates of ulcers and amputations. We compared initial and cumulative ulcer/amputation incidence to account for multiple events in the same person over time. We used the same formula to determine the incidence rate difference and 95% confidence intervals (CIs) to compare new ulcers and amputations during the study. RESULTS: There was no significant difference in the incidence of first foot ulcers before (91.7 per 1,000 patient-years; 95% CI, 73.7-112.3 per 1,000 patient-years) and after (82.7; 95% CI, 65.7-102.3) the start of hemodialysis. The incidence of cumulative ulcers was significantly higher before (304.0 per 1,000 patient-years; 95% CI, 270.8-340.2) compared with after (210.7 per 1,000 patient-years; 95% CI, 183.0-240.9) dialysis. There was no difference in the incidence of first amputation before (29.3 per 1,000 patient-years; 95% CI, 1 9.4-41.7 per 1,000 patient-years) and after (37.3 per 1,000 patient-years; 95% CI, 19.4-41.7 per 1,000 patient-years) dialysis or in the cumulative incidence of amputations before (61.3 per 1,000 patient-years; 95% CI, 46.7-8.4 per 1,000 patient-years) and after (58.7 per 1,000 patient-years; 95% CI, 44.5-75.5 per 1,000 patient-years) dialysis. CONCLUSIONS: There was no increase in the incidence of ulcers or amputations after beginning hemodialysis.

Split-Thickness Skin Grafts to the Foot and Ankle of Diabetic Patients.

BACKGROUND: There is an increased prevalence of foot ulceration in patients with diabetes, leading to hospitalization. Early wound closure is necessary to prevent further infections and, ultimately, lower-limb amputations. There is no current evidence stating that an elevated preoperative hemoglobin A1c (HbA1c) level is a contraindication to skin grafting. The purpose of this review was to determine whether elevated HbA1c levels are a contraindication to the application of skin grafts in diabetic patients. METHODS: A retrospective review was performed of 53 consecutive patients who underwent split-thickness skin graft application to the lower extremity between January 1, 2012, and December 31, 2015. A uniform surgical technique was used across all of the patients. A comparison of HbA1c levels between failed and healed skin grafts was reviewed. RESULTS: Of 43 surgical sites (41 patients) that met the inclusion criteria, 27 healed with greater than 90% graft take and 16 had a skin graft that failed. There was no statistically significant difference in HbA1c levels in the group that healed a skin graft compared with the group in which skin graft failed to adhere. CONCLUSIONS: Preliminary data suggest that an elevated HbA1c level is not a contraindication to application of a skin graft. The benefits of early wound closure outweigh the risks of skin graft application in patients with diabetes.

Fracture healing and biomarker expression in a diabetic Zucker rat model.

BACKGROUND: Persons with diabetes have a higher incidence of fractures compared with persons without diabetes. However, there is little published information concerning the deleterious effect of late-stage diabetes on fracture healing. There are no studies using animal models that evaluate the effect of advanced diabetes on fracture healing. The purpose of our study was to evaluate cytokine expression, specifically macrophage inflammatory protein 1 (MIP-1) and vascular endothelial growth factor, in fracture healing in a type 2 diabetes rat model. METHODS: We evaluated biomarker expression after femur fracture using a rat model. The two groups consisted of 24 Zucker diabetic rats (study group) and 12 Zucker lean rats (control group). An independent reviewer was used to assess delayed union. We evaluated serum samples 2, 4, 7, and 14 days after surgery for MIP-1, vascular endothelial growth factor, leptin, and other cytokine levels. RESULTS: At 3 weeks, Kaplan-Meier estimates showed that 45.8% of femur fractures in Zucker diabetic rats had healed, whereas 81.8% of those in Zucker lean rats had healed (P = .02). A logistic regression model to predict fast healing that included the three cytokines and diabetes status showed that the only factor achieving significance was MIP-1α. Vascular endothelial growth factor was the only biomarker to show significance compared with delayed healing. CONCLUSIONS: These results confirm significant differences in biomarker expression between diabetic and nondiabetic rats during bone healing. The key factors for bone healing may appear early in the healing process, whereas differences in diabetes versus nondiabetes are seen later in the healing process. Increased levels of MIP-1α were associated with the likelihood of delayed healing.

Negative Pressure Wound Therapy With Low Pressure and Gauze Dressings to Treat Diabetic Foot Wounds.

This study was a prospective cohort study to evaluate negative pressure wound therapy (NPWT) with low pressure and a gauze dressing to treat diabetic foot wounds. Thirty patients with diabetic foot wounds were consented to a prospective study to evaluate wound closure and complications to evaluate NPWT with low pressure (80 mmHg) and a gauze dressing interface (EZCare, Smith and Nephew) for up to 5 weeks. NPWT was changed 3 times a week. Study subjects were evaluated once a week for adverse events and wound measurements. Of study subjects, 43% attained at least a 50% wound area reduction after 4 weeks of therapy. Our results suggest that a high rate of wound closure could be expected with low pressure and a gauze interface.

Risk factors for methicillin-resistant Staphylococcus aureus in diabetic foot infections.

OBJECTIVE: The purpose of this study was to evaluate risk factors for methicillin-resistant Staphylococcus aureus (MRSA) in patients hospitalized for diabetic foot infections. METHODS: We reviewed hospital admissions for foot infections in patients with diabetes which had nasal swabs, and anaerobic and aerobic tissue cultures at the time of admission. Data collected included patient characteristics and medical history to determine risk factors for developing an MRSA infection in the foot. RESULTS: The prevalence of MRSA in these infections was 29.8%. Risk factors for MRSA diabetic foot infections were history of MRSA foot infection, MRSA nasal colonization, and multidrug-resistant organisms (p<0.05). Positive predictive value (PPV) and negative predictive value (NPV) of nasal colonization with MRSA to identify MRSA diabetic foot infections were 66.7% and 80.0% (sensitivity 41%, specificity 90%). Admission from a nursing home was not a significant risk factor. CONCLUSION: Positive nasal swabs are not predictive of the infecting agent; however, a negative nasal swab rules out MRSA as the infecting agent in foot wounds with 90% accuracy.