Lawrence B. Harkless

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.

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).

Lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot

BACKGROUND The purpose of this study was to determine the degree to which pressure on the plantar aspect of the forefoot is reduced following percutaneous lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot. METHODS Ten diabetic patients who had a history of neuropathic plantar ulceration of the forefoot were enrolled in a laboratory gait trial. A repeated-measures design and a computer analysis of force-plate data were used to examine dynamic pressures on the forefoot, with the patient walking barefoot, immediately before percutaneous lengthening of the Achilles tendon and at eight weeks afterward. Although the wound in each patient had healed at least one month before the operation, we considered the patients to be at high risk for ulceration because they had had an ulcer previously. RESULTS The mean peak pressure (and standard deviation) on the plantar aspect of the forefoot decreased significantly from 86+/-9.4 newtons per square centimeter preoperatively to 63+/-13.2 newtons per square centimeter at eight weeks postoperatively (p<0.001). Commensurately, the mean dorsiflexion of the ankle joint increased significantly from 0+/-3.1 degrees preoperatively to 9+/-2.3 degrees at eight weeks post-operatively (p<0.001). CONCLUSIONS The results of this study suggest that peak pressures on the plantar aspect of the forefoot are significantly reduced following percutaneous lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot. We are unaware of any other reports in the medical literature that describe such findings. These data may lend support to studies that have indicated that this procedure should be used as an adjunctive therapeutic or prophylactic measure to reduce the risk of neuropathic ulceration.

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.

Guidelines for the treatment of diabetic ulcers

1. Chaired this panel2. University of Pittsburgh/UPMC, Pittsburgh, PA3. Georgetown University Hospital, Washington, DC4. Colaizzi Pedorthic Center, Pittsburgh, PA5. HCA Richmond Retreat Hospital, Richmond, VA6. University of Michigan Hospital, Ann Arbor, MI7. University of Texas Health Science Center, San Antonio, TX8. Covance, Princeton, NJ9. St Joseph’s Hospital, Belleville, IL10. University of South Florida, Tampa, FL11. Penn North Centers for Advanced Wound Care, Warren, PA12. Cabrini Medical Center, NY, NY13. Beth Israel Deaconess Medical Center, Boston, MA, and14. Barnes-Jewish Hospital at Washington University Medical Center, St Louis, MO

The impact of diabetes-related lower-extremity amputations in the Netherlands

The purpose of this study is to identify the incidence of diabetes-related lower-extremity amputations in the Netherlands. We used discharge records from SIG Health Care Information for every hospitalization for a lower-extremity amputation in all hospitals in the Netherlands in 1992. Age- and gender-specific population figures and diagnosed cases of diabetes were obtained from the Central Bureau of Statistics. Age- and gender-adjusted amputation incidences were identified at four different levels (toe, foot, leg, and thigh). Multiple amputations were analyzed by the highest level. Of all lower-extremity amputations, 1,575 (47%) were in persons with diabetes mellitus. Age- and gender-adjusted lower-extremity amputation rates per 10,000 persons with diabetes by level were the following: toe 12.39, foot 2.42, leg 7.82, thigh 2.54, and total 25.17. People with diabetes were 20.3 times more likely to experience a lower-extremity amputation than people without diabetes. Males were at a significantly higher risk of experiencing an amputation than females. There was a significant increase in the age-specific incidence of amputations as age increased. The most common amputation procedure performed was the toe amputation. There was a significant increase in thigh amputations as age increased, indicating that as people get older they suffer higher levels of amputations. Although the incidence of lower-extremity amputations was lower than previous reports, they still have a serious impact on the health-care system in the Netherlands.

Treatment-based Classification System for Assessment and Care of Diabetic Feet

Appropriate care of feet of patients with diabetes 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. The authors report on a logical, treatment-oriented system that may 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 Charcots 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). Acute Charcots arthropathy requires prompt, uncompromising reduction in weightbearing stress. Our data show that the ambulatory total contact cast is very effective for this. Regardless of the specific treatment method instituted, it is imperative that appropriate and aggressive treatment be undertaken immediately following diagnosis to help prevent progression to a profoundly debilitating, limb-threatening deformity.