Lawrence A. Lavery

Validation of a Diabetic Wound Classification System: The contribution of depth, infection, and ischemia to risk of amputation

OBJECTIVE To validate a wound classification instrument that includes assessment of depth, infection, and ischemia based on the eventual outcome of the wound. RESEARCH DESIGN AND METHODS We evaluated the medical records of 360 diabetic patients presenting for care of foot wounds at a multidisciplinary tertiary care foot clinic. As per protocol, all patients had a standardized evaluation to assess wound depth, sensory neuropathy, vascular insufficiency, and infection. Patients were assessed at 6 months after their initial evaluation to see whether an amputation had been performed. RESULTS There was a significant overall trend toward increased prevalence of amputations as wounds increased in both depth (χ2trend = 143.1, P < 0.001) and stage (χ2trend = 91.0, P < 0.001). This was true for every subcategory as well with the exception of noninfected, nonischemic ulcers. There were no amputations performed within this stage during the follow-up period. Patients were more than 11 times more likely to receive a midfoot or higher level amputation if their wound probed to bone (18.3 vs. 2.0%, P < 0.001, χ2 = 31.5, odds ratio (OR) = 11.1, CI = 4.0–30.3). Patients with infection and ischemia were nearly 90 times more likely to receive a midfoot or higher amputation compared with patients in less advanced wound stages (76.5 vs. 3.5%, P < 0.001, χ2 = 133.5, OR = 89.6, CI = 25–316). CONCLUSIONS Outcomes deteriorated with increasing grade and stage of wounds when measured using the University of Texas Wound Classification System.

Negative pressure wound therapy after partial diabetic foot amputation: a multicentre, randomised controlled trial

BACKGROUND Diabetic foot wounds, particularly those secondary to amputation, are very complex and difficult to treat. We investigated whether negative pressure wound therapy (NPWT) improves the proportion and rate of wound healing after partial foot amputation in patients with diabetes. METHODS We enrolled 162 patients into a 16-week, 18-centre, randomised clinical trial in the USA. Inclusion criteria consisted of partial foot amputation wounds up to the transmetatarsal level and evidence of adequate perfusion. Patients who were randomly assigned to NPWT (n=77) received treatment with dressing changes every 48 h. Control patients (n=85) received standard moist wound care according to consensus guidelines. NPWT was delivered through the Vacuum Assisted Closure (VAC) Therapy System. Wounds were treated until healing or completion of the 112-day period of active treatment. Analysis was by intention to treat. This study has been registered with , number NCT00224796. FINDINGS More patients healed in the NPWT group than in the control group (43 [56%] vs 33 [39%], p=0.040). The rate of wound healing, based on the time to complete closure, was faster in the NPWT group than in controls (p=0.005). The rate of granulation tissue formation, based on the time to 76-100% formation in the wound bed, was faster in the NPWT group than in controls (p=0.002). The frequency and severity of adverse events (of which the most common was wound infection) were similar in both treatment groups. INTERPRETATION NPWT delivered by the VAC Therapy System seems to be a safe and effective treatment for complex diabetic foot wounds, and could lead to a higher proportion of healed wounds, faster healing rates, and potentially fewer re-amputations than standard care.

Comprehensive Foot Examination and Risk Assessment A report of the Task Force of the Foot Care Interest Group of the American Diabetes Association, with endorsement by the American Association of Clinical Endocrinologists

It is now 10 years since the last technical review on preventative foot care was published (1), which was followed by an American Diabetes Association (ADA) position statement on preventive foot care in diabetes (2). Many studies have been published proposing a range of tests that might usefully identify patients at risk of foot ulceration, creating confusion among practitioners as to which screening tests should be adopted in clinical practice. A task force was therefore assembled by the ADA to address and concisely summarize recent literature in this area and then recommend what should be included in the comprehensive foot exam for adult patients with diabetes. The committee was cochaired by the immediate past and current chairs of the ADA Foot Care Interest Group (A.J.M.B. and D.G.A.), with other panel members representing primary care, orthopedic and vascular surgery, physical therapy, podiatric medicine and surgery, and the American Association of Clinical Endocrinologists. The lifetime risk of a person with diabetes developing a foot ulcer may be as high as 25%, whereas the annual incidence of foot ulcers is ∼2% (3–7). Up to 50% of older patients with type 2 diabetes have one or more risk factors for foot ulceration (3,6). A number of component causes, most importantly peripheral neuropathy, interact to complete the causal pathway to foot ulceration (1,3–5). A list of the principal contributory factors that might result in foot ulcer development is provided in Table 1. View this table: Table 1— Risk factors for foot ulcers The most common triad of causes that interact and ultimately result in ulceration has been identified as neuropathy, deformity, and trauma (5). As identification of those patients at risk of foot problems is the first step in preventing such complications, this report will focus on key components of the …

Role of Neuropathy and High Foot Pressures in Diabetic Foot Ulceration

OBJECTIVE High plantar foot pressures in association with peripheral neuropathy have been ascertained to be important risk factors for ulceration in the diabetic foot. Most studies investigating these parameters have been limited by their size and the homogeneity of study subjects. The objective of this study was therefore to ascertain the risk of ulceration associated with high foot pressures and peripheral neuropathy in a large and diverse diabetic population. RESEARCH DESIGN AND METHODS We studied a cross-sectional group of 251 diabetic patients of Caucasian (group C) (n = 121), black (group B) (n = 36), and Hispanic (group H) (n = 94) racial origins with an overall age of 58.5 ± 12.5 years (range 20–83). There was an equal distribution of men and women across the entire study population. All patients underwent a complete medical history and lower extremity evaluation for neuropathy and foot pressures. Neuropathic parameters were dichotomized (0/1) into two high-risk variables: patients with a vibration perception threshold (VPT) ≥25 V were categorized as HiVPT (n = 132) and those with Semmes-Weinstein monofilament tests ≥5.07 were classified as HiSWF (n = 190). The mean dynamic foot pressures of three footsteps were measured using the F-scan mat system with patients walking without shoes. Maximum plantar pressures were dichotomized into a high-pressure variable (Pmax6) indicating those subjects with pressures ≥6 kg/cm2 (n = 96). A total of 99 patients had a current or prior history of ulceration at baseline. RESULTS Joint mobility was significantly greater in the Hispanic cohort compared with the other groups at the first metatarsal-phalangeal joint (C 67 ± 23°, B 69 ± 23°, H 82 ± 23°, P = 0.000), while the subtalar joint mobility was reduced in the Caucasian group (C 21 ± 8°, B 26 ± 7°, H 27 ± 11°, P = 0.000). Maximum plantar foot pressures were significantly higher in the Caucasian group (C 6.7 ± 2.9 kg/cm2, B 5.7 ± 2.8 kg/cm2, H 4.4 ±1.9 kg/cm2 P = 0.000). Univariate logistic regression for Pmax6 on the history of ulceration yielded an odds ratio (OR) of 3.9 (P = 0.000). For HiVPT, the OR was 11.7 (P = 0.000), and for HiSWF, the OR was 9.6 (P = 0.000). Controlling for age, diabetes duration, sex, and race (all P < 0.05), multivariate logistic regression yielded the following significant associations with ulceration: Pmax6 (OR = 2.1, P = 0.002), HiVPT (OR = 4.4, P = 0.000), and HiSWF (OR = 4.1, P = 0.000). CONCLUSIONS We conclude that both high foot pressures (≥6 kg/cm2) and neuropathy are independently associated with ulceration in a diverse diabetic population, with the latter having the greater magnitude of effect. In black and Hispanic diabetic patients especially, joint mobility and plantar pressures are less predictive of ulceration than in Caucasians.

Classification of diabetic foot wounds

Foot ulcers in persons with diabetes are one of the most common precursors to lower extremity amputation. Appropriate care of the diabetic foot ulceration requires a clear, descriptive classification system that may be used to direct appropriate therapy and possibly predict outcome. Ideally, this system would be used by all participants in a multidisciplinary limb salvage team. We describe a clinical classification system for diabetic foot wounds that evaluates wound depth, the presence of infection, and peripheral arterial occlusive disease in every category of the wound assessment. The goal of this system is to improve communication, leading to a less complex, more predictable treatment course and, ultimately, an improved result.

The natural history of acute Charcot's arthropathy in a diabetic foot specialty clinic.

The aim of this longitudinal study was to report on the clinical characteristics and treatment course of acute Charcot’s arthropathy at a tertiary care diabetic foot clinic. Fifty‐five diabetic subjects, with a mean age of 58.6 ± 8.5 years, were studied. All patients were treated with serial total contact casting until quiescence. Following casting and before transfer to prescription footwear, patients were eased into unprotected weightbearing via a removable cast walker. This cohort was followed for their entire treatment course and for a mean 92.6 ± 33.7 weeks following return to shoes. Pain was the most frequent presenting complaint in these otherwise insensate patients (76 %). The mean duration of casting was 18.5 ± 10.6 weeks. Patients returned to footwear in a mean 28.3 ± 14.5 weeks. Nine per cent of the population had bilateral arthropathy. These subjects were casted significantly longer than the unilateral group (p < 0.02). Surgery was performed on 25 % of patients, with approximately two‐thirds of these procedures involving plantar exostectomies and one‐third fusions of affected joints. Patients receiving surgery remained casted significantly longer than non‐surgical patients (p < 0.05). Additionally, men were casted longer than women (p < 0.008).

Variation in the Incidence and Proportion of Diabetes-Related Amputations in Minorities

OBJECTIVE To identify the age-adjusted and level-specific incidence of amputations associated with diabetes in Hispanics, African-Americans, and non-Hispanic whites. RESEARCH DESIGN AND METHODS We used a database from the Office of Statewide Planning and Development in California that identified all hospitalizations for lower-extremity amputations in the state in 1991. Amputation level was defined by ICD-9-CM codes 84.11–84.18 and were categorized as toe, foot, leg, and thigh amputations. RESULTS The age-adjusted incidence of diabetes-related amputation per 10,000 persons with diabetes in 1991 was 95.25 in African-Americans, 55.98 in non-Hispanic whites, and 44.43 in Hispanics. Hispanics had a higher proportion of amputations (82.7%) associated with diabetes than did African-Americans (61.6%) or non-Hispanic whites (56.8%) (P < 0.001). African-Americans had the highest age-adjusted incidence rate for each level in people with and without diabetes. African-Americans underwent more proximal amputations compared with non-Hispanic whites and Hispanics (P < 0.001). Diabetes-related amputations were 1.72 and 2.17 times more likely in African-Americans compared with non-Hispanic whites and Hispanics, respectively. CONCLUSIONS Hispanics had proportionally more amputations associated with diabetes than did African-Americans or non-Hispanic whites. A significant excess incidence of both diabetes- and non-diabetes-related amputations and proportionally more proximal amputations were identified in African-Americans compared with Hispanics and non-Hispanic whites. A possible explanation could be the higher prevalence of peripheral vascular disease in African-Americans. Public health initiatives, which have been demonstrated to reduce the incidence of diabetes-related lower-extremity amputations, should be implemented, and additional work should focus on minority groups.

Preventing diabetic foot ulcer recurrence in high-risk patients : Use of temperature monitoring as a self-assessment tool

OBJECTIVE—The purpose of this study was to evaluate the effectiveness of a temperature monitoring instrument to reduce the incidence of foot ulcers in individuals with diabetes who have a high risk for lower extremity complications. RESEARCH DESIGN AND METHODS—In this physician-blinded, randomized, 15-month, multicenter trial, 173 subjects with a previous history of diabetic foot ulceration were assigned to standard therapy, structured foot examination, or enhanced therapy groups. Each group received therapeutic footwear, diabetic foot education, and regular foot care. Subjects in the structured foot examination group performed a structured foot inspection daily and recorded their findings in a logbook. If standard therapy or structured foot examinations identified any foot abnormalities, subjects were instructed to contact the study nurse immediately. Subjects in the enhanced therapy group used an infrared skin thermometer to measure temperatures on six foot sites each day. Temperature differences >4°F (>2.2°C) between left and right corresponding sites triggered patients to contact the study nurse and reduce activity until temperatures normalized. RESULTS—The enhanced therapy group had fewer foot ulcers than the standard therapy and structured foot examination groups (enhanced therapy 8.5 vs. standard therapy 29.3%, P = 0.0046 and enhanced therapy vs. structured foot examination 30.4%, P = 0.0029). Patients in the standard therapy and structured foot examination groups were 4.37 and 4.71 times more likely to develop ulcers than patients in the enhanced therapy group. CONCLUSIONS—Infrared temperature home monitoring, in serving as an “early warning sign,” appears to be a simple and useful adjunct in the prevention of diabetic foot ulcerations.

Validation of the Infectious Diseases Society of America's Diabetic Foot Infection Classification System

In this longitudinal study of 1666 persons with diabetes, there was an observed trend toward an increased risk for amputation (chi(2) test for trend, 108.0; P<.001), higher-level amputation (chi(2) test for trend, 113.3; P<.001), and lower extremity-related hospitalization (chi(2) test for trend, 118.6; P<.001) with increasing infection severity. The Infectious Diseases Society of Americas foot infection classification system may be a useful tool for grading foot infections.

Is there a critical level of plantar foot pressure to identify patients at risk for neuropathic foot ulceration

The purpose of this study was to identify a point along the spectrum of peak plantar forefoot pressure that has an optimum combination of sensitivity and specificity to screen for neuropathic ulceration. We enrolled 219 diabetic patients in this case-control study in an approximate 2:1 control:case ratio. Cases were defined as patients with an active or recently healed neuropathic ulceration. Controls were defined as those with no history of ulceration. All patients had peak plantar pressures analyzed with the EMED gait analysis system. Peak plantar pressure was, as expected, significantly higher for patients with ulcers compared to controls [83.1 +/- 24.7 N/cm2 (range, 10-125) vs. 62.7 +/- 24.4 N/cm2 (range, 7.3-113), p < .001]. The ulcer group was clearly skewed toward a higher prevalence of elevated peak plantar forefoot pressure compared with the control group, which displayed the opposite trend (control group skewness = 0.286, kurtosis = -0.482; ulcer group skewness = -0.389, kurtosis = -0.289). Using receiver operating characteristic analysis, the optimal cut-point, as determined by a balance of sensitivity and specificity was 70 N/cm2, which yielded a sensitivity of 70.0% and a specificity of 65.1%. We concluded that, while there is no optimal cut-point for clearly screening patients for risk of foot ulceration, the higher the peak pressure, the higher the commensurate risk.