Electric stimulation as an adjunct to heal diabetic foot ulcers: a randomized clinical trial.

OBJECTIVE: To evaluate high-voltage, pulse-galvanic electric stimulation as an adjunct to healing diabetic foot ulcers. DESIGN: Randomized, double-blind, placebo-controlled pilot trial. SETTING: University medical center. PATIENTS: Forty patients with diabetic foot ulcers, consecutively sampled. Twenty patients each assigned to treatment and placebo groups. Five patients (2 treated, 3 placebo) withdrew because of severe infection. INTERVENTIONS: Electric stimulation through a microcomputer every night for 8 hours. The placebo group used identical functioning units that delivered no current. Additional wound care consisted of weekly débridements, topical hydrogel, and off-loading with removable cast walkers. Patients were followed for 12 weeks or until healing, whichever occurred first. MAIN OUTCOME MEASURES: Proportion of wounds that healed during the study period. Compliance with use of device (in hr/wk), rate of wound healing, and time until healing. RESULTS: Sixty-five percent of the patients healed in the group treated with stimulation, whereas 35% healed with placebo (p = .058). After stratification by compliance, a significant difference was identified among compliant patients in the treatment group (71% healed), noncompliant patients in the treatment group (50% healed), compliant patients in the placebo group (39% healed), and noncompliant patients in the placebo group (29% healed, linear-by-linear association = 4.32, p = .038). There was no significant difference in compliance between the 2 groups. CONCLUSION: Electric simulation enhances wound healing when used in conjunction with appropriate off-loading and local wound care.

Effects of diabetes mellitus on the biomechanical properties of human ankle cartilage.

Metabolic changes attributable to diabetes mellitus affect numerous organ systems in the body. For example, patients with diabetes have an increased number of musculoskeletal injuries and afflictions compared with patients without diabetes and experience more morbidity associated with injury and treatment. Although diabetes also may afflict articular cartilage, no studies have shown a conclusive link between diabetes and cartilage structural integrity. The objective of this study was to obtain and compare the intrinsic material properties of human ankle articular cartilage from patients with diabetes and those without diabetes. These biomechanical properties (aggregate modulus, Poisson's ratio, shear modulus, and permeability) were found to differ significantly between specimens from patients with diabetes and patients without diabetes. Specifically, cartilage from patients with diabetes was significantly softer and more permeable than cartilage from control subjects. For example, in the central portion of the talus, cartilage from patients with diabetes had a 38% smaller aggregate modulus, 37% smaller shear modulus, and 111% larger permeability than did tissue from patients without diabetes. These results provide evidence that joint pathologic processes in patients with diabetes may be associated with compromised structural integrity of articular cartilage.

Treatment of posterior tibial tendon dysfunction with tendon procedures from the posterior muscle group.

The use of tendons from the posterior muscle group, specifically the FDL, as a means to repair PTTD is useful for the early stages of the deformity. Once the patient has reached the later stages and the foot becomes rigidly deformed with loss of the medial longitudinal arch, however, any attempt to reconstruct the area with tendon work alone fails. Tendon repair, tenodesis, and tendon transfer are attractive treatment options for PTTD, but care should be taken in choosing the correct patient for these procedures. Some authors note that side-to-side tenodesis does not address arch realignment. Other procedures combined with tendon work perhaps can help to reduce the shortcomings of isolated tendon procedures. Subtalar joint arthroeresis in combination with the tendon work seems to solve this problem. The authors have begun to explore this option and have performed this procedure on some patients. It is premature to address the effectiveness of this combined procedure. Similarly, tendon procedures augmented with other soft-tissue-type procedures also remains an option and is mostly ignored in the medical literature. Deland et al experimented with reconstruction of the spring ligament in a cadaver study, and believed that it should be considered in any reconstructive flatfoot surgery. Likewise, Myerson used some capsular reefing of the talonavicular joint in his tendon reconstruction to aid the correction of the forefoot-to-rearfoot relationship. The treatment of the patient with PTTD remains driven by the surgeon's preference, with little scientific research to guide him or her. There is much controversy regarding the efficacy of tendon procedures and the specific surgical technique of each procedure. Some variations may prove inconsequential, whereas others may prove revolutionary. The authors believe that the use of the tendon work as a means of treatment for PTTD is viable alone or in combination with other procedures. Much research is still needed to identify the best technique for each stage of the deformity. Wiekland has attempted to do this, but unfortunately has not offered any long-term follow-up to justify his treatment algorithms. Foot and ankle specialists should strive for clinical research, which allows better understanding of the appropriate treatment options for each progressive stage of PTTD.

The effects of diabetes mellitus on the material properties of human metatarsal bones.

While some investigations have focused on the effect of diabetes on the material properties of connective tissue in both the human and animal model, no study to date has investigated the effects of the disease process on human metatarsal bones. This investigation compared the material properties of human metatarsal bones from young diabetic donors (51.3 +/- 8 years) and older nondiabetic donors (72.3 +/- 10 years). The results demonstrated no significant differences between the two groups. This would seem to suggest that the effects of aging are comparable to the effects of diabetes on the structural integrity of human metatarsal bones.

Choosing a practical screening instrument to identify patients at risk for diabetic foot ulceration.

OBJECTIVE: To evaluate the sensitivity and specificity of 3 sensory perception testing instruments to screen for risk of diabetic foot ulceration. METHODS: This case-control study prospectively measured the degree of peripheral sensory neuropathy in diabetic patients with and without foot ulcers. We enrolled 115 age-matched diabetic patients (40% male) with a case-control ratio of approximately 1:3 (30 cases and 85 controls) from a tertiary care diabetic foot specialty clinic. Cases were defined as individuals who had an existing foot ulceration or a history of a recently (< 4 weeks) healed foot ulceration. Controls were defined as subjects with no foot ulceration history. Using receiver operating characteristic analysis, we evaluated the sensitivity and specificity of 2 commonly used nephropathy assessment tools (vibration perception threshold testing and the Semmes-Weinstein 10-g monofilament wire system) and a 4-question verbal neuropathy score to evaluate for presence of foot ulceration. RESULTS: A vibration perception threshold testing using 25 V and lack of perception at 4 or more sites using the Semmes-Weinstein 10-g monofilament wire system had a significantly higher specificity than neuropathy score used. The neuropathy score was most sensitive when 1 or more answers were affirmative. When modalities were combined, particularly the monofilament wire system plus vibration perception threshold testing and the neuropathy score plus the monofilament wire system, there was a substantial increase in specificity with little or no diminution in sensitivity. CONCLUSIONS: The early detection of peripheral neuropathy or loss of "protective sensation" is paramount to instituting a structured treatment plan to prevent lower extremity amputation. The results of our study suggest that all 3 sensory perception testing instruments are sensitive in identifying patients at risk for ulceration. Combining modalities appears to increase specificity with very little or no diminution in sensitivity.

Practical criteria for screening patients at high risk for diabetic foot ulceration.

BACKGROUND: A comprehensive understanding of clinical risk factors for developing foot ulcerations would help clinicians to categorize patients by their risk status and schedule intervention resources accordingly to prevent amputation. OBJECTIVE: To evaluate risk factors for foot ulcerations among persons with diabetes mellitus. METHOD: We enrolled 225 age-matched patients, 46.7% male, with a ratio of approximately 1:2 cases: controls (76 case-patients and 149 control subjects). Case-patients were defined as subjects who met the enrollment criteria and who had an existing foot ulceration or a recent history of a foot ulceration. Control subjects were defined as subjects with no history of foot ulceration. A stepwise logistic regression model was used for analysis. RESULTS: An elevated plantar pressure (> 65 N/cm2), history of amputation, lengthy duration of diabetes (> 10 years), foot deformities (hallux rigidus or hammer toes), male sex, poor diabetes control (glycosylated hemoglobin > 9%), 1 or more subjective symptoms of neuropathy, and an elevated vibration perception threshold (> 25 V) were significantly associated with foot ulceration. In addition, 59 patients (78%) with ulceration had a rigid deformity directly associated with the site of ulceration. No significant associations were noted between vascular disease, level of formal education, nephropathy, retinopathy, impaired vision, or obesity and foot ulceration on multivariate analysis. CONCLUSIONS: Neuropathy, foot deformity, high plantar pressures, and a history of amputation are significantly associated with the presence of foot ulceration. Although vascular and renal disease may result in delayed wound healing and subsequent amputation, they are not significant risk factors for the development of diabetic foot ulceration.

Reducing plantar pressure in the neuropathic foot. A comparison of footwear.

OBJECTIVE: To compare the effectiveness of therapeutic, comfort, and athletic shoes with and without viscoelastic insoles. RESEARCH DESIGN AND METHODS: We compared pressure reduction at ulcer sites under the hallux (n = 10), first metatarsal (n = 10), and lesser metatarsals (n = 12), using extra-depth, athletic, and comfort shoes with and without viscoelastic insoles. A rubber-soled canvas oxford was used to establish baseline pressure values. RESULTS: When used in conjunction with a viscoelastic insole, all shoe types reduced mean peak plantar pressure better than their non-insoled counterparts (P < 0.05). Consistently, comfort shoes reduced pressure significantly better than both the cross trainers and extra-depth shoes for ulcers under the first and lesser metatarsals (P < 0.05). For each shoe type, the addition of the viscoelastic insole provided a significant reduction in mean peak pressure (P < 0.05). Compared with stock insoles, viscoelastic insoles reduced pressures an additional 5.4-20.1% at ulcer sites. The same trend was also observed at regions of the foot not associated with an ulceration. CONCLUSIONS: When used in conjunction with a viscoelastic insole, both the comfort and athletic cross-trainer shoes studied were as, if not more, effective than commonly prescribed therapeutic shoes in reducing mean peak first and lesser metatarsal pressures. Furthermore, comfort shoes were as effective as therapeutic shoes in reducing pressure under the great toe. Both of these shoe types may be viable options to prevent the development or recurrence of foot ulcers.

1997 William J. Stickel Bronze Award. Comparison of strategies for reducing pressure at the site of neuropathic ulcers.

Few scientific data are available on the effectiveness of commonly used modalities for reducing pressure at the site of neuropathic ulcers in persons with diabetes mellitus. The authors' aim was to compare the effectiveness of total contact casts, half-shoes, rigid-soled postoperative shoes, accommodative dressings made of felt and polyethylene foam, and removable walking casts in reducing peak plantar foot pressures at the site of neuropathic ulcerations in diabetics. Using an in-shoe pressure-measurement system, data from 32 midgait steps were collected for each treatment. There was a consistent pattern in the devices' effectiveness in reducing foot pressures at ulcer sites under the great toe and ball of the foot. Removable walking casts were as effective as or more effective than total contact casts. Half-shoes were consistently the third most effective modality, followed by accommodative dressings and rigid-soled postoperative shoes.

Is electrical stimulation effective in reducing neuropathic pain in patients with diabetes?

Pulsed-dose electrical stimulation is evaluated as an analgesic modality in patients-with painful diabetic neuropathy. Using a knitted silver-plated nylon/dacron stocking electrode, patients were given electrical stimulation over the course of 1 month. Pain was measured weekly, using a 10-cm. visual analog scale. Pain measurements at the end of the 4-week therapy and at 1 month after complete discontinuation of therapy were significantly lower than at the initiation of therapy. The results of this pilot study suggest that nocturnal doses of pulsed-electrical stimulation may be effective in alleviating subjective, burning, diabetic neuropathic pain in a population consisting of patients with grossly intact protective sensation, relatively good distal vascular perfusion and less than ideal glucose control. To the authors' knowledge, this is the first analytic report of pulsed-dose electrical nerve stimulation delivered through a stocking electrode for treatment of symptomatic diabetic neuropathy in medical literature.

Electrical stimulation in wound healing.

The authors present a review of the current literature regarding electrical stimulation with special focus on the merits of its uses in wound healing. Literature from a basic science, animal studies and clinical investigations are reviewed. The literature seems to suggest that electrical stimulation can effect wound healing, but the method of delivery remains uncertain.

Identification and treatment of the diabetic neuropathic foot.

The authors discuss neuropathic osteoarthropathy in the diabetic foot, often associated with Charcot joints. Identification of this malady as well as indications for treatment are reviewed. Representative cases are illustrated.