The Forefoot-to-Rearfoot Plantar Pressure Ratio Is Increased in Severe Diabetic Neuropathy and Can Predict Foot Ulceration

Abstract

OBJECTIVE -We have previously demonstrated that high plantar pressures can predict foot ulceration in diabetic patients. The aim of the present study was to evaluate both the relationship between forefoot and rearfoot plantar pressure in diabetic patients with different degrees of peripheral neuropathy and their role in ulcer development. RESEARCH DESIGN AND METHODS-Diabetic patients of a 30-month prospective study were classified according to the neuropathy disability score: scores of 0, 1-5, 6 -16, and 17-28 are defined as absent (n ϭ 20), mild (n ϭ 66), moderate (n ϭ 95), and severe (n ϭ 57) neuropathy, respectively. The F-Scan mat system was used to measure dynamic plantar pressures. The peak pressures under the forefoot and the rearfoot were selectively measured for each foot, and the forefoot-to-rearfoot ratio (F/R ratio) was calculated.RESULTS -Foot ulcers developed in 73 (19%) feet. The peak pressures were increased in the forefoot of the severe and moderate neuropathic groups compared with the mild neuropathic and nonneuropathic groups (6.2 Ϯ 4.5 and 3.8 Ϯ 2.7 vs. 3.0 Ϯ 2.1 and 3.3 Ϯ 2.1 kg/cm 2 [mean Ϯ SD], respectively; P Ͻ 0.0001). The rearfoot pressures were also higher in the severe and moderate neuropathic groups compared with the mild neuropathic and nonneuropathic groups (3.2 Ϯ 2.0 and 3.2 Ϯ 1.9 vs. 2.5 Ϯ 1.3 and 2.3 Ϯ 1.0, respectively; P Ͻ 0.0001). The F/R ratio was increased only in the severe group compared with the moderate and mild neuropathic and nonneuropathic groups (2.3 Ϯ 2.4 vs. 1.5 Ϯ 1.2, 1.3 Ϯ 0.9, and 1.6 Ϯ 1.0, respectively; P Ͻ 0.0001). In a logistic regression analysis, both forefoot pressure (odds ratio 1.19 [95% CI 1.11-1.28], P Ͻ 0.0001) and the F/R ratio (1.37 [1.16 -1.61], P Ͻ 0.0001) were related to risk of foot ulceration, whereas rearfoot pressure was not.CONCLUSIONS -Both the rearfoot and forefoot pressures are increased in the diabetic neuropathic foot, whereas the F/R ratio is increased only in severe diabetic neuropathy, indicating an imbalance in pressure distribution with increasing degrees of neuropathy. This may lend further evidence toward the concept that equinus develops in the latest stages of peripheral neuropathy and may play an important role in the etiology of diabetic foot ulceration.

Biomechanical characteristics of peripheral diabetic neuropathy: A systematic review and meta-analysis of findings from the gait cycle, muscle activity and dynamic barefoot plantar pressure

“…The majority of 'good quality' studies also used a means of 224 adjustment for confounding with or without using multiple regression analysis. time frames for recruitment, as it was a part of a larger study (Caselli et al, 2002). For other studies 238 this could not be determined.…”

Custom Therapeutic Insoles Based on Both Foot Shape and Plantar Pressure Measurement Provide Enhanced Pressure Relief

“…Plantar pressure measurement has been proposed as an indicator of risk in patients with diabetes (19,20), although barefoot peak pressure has been reported to be only moderately sensitive and specific as a predictor of ulcer location. Elevated barefoot plantar pressure has, however, been shown in one prospective study to be predictive of ulceration (21).…”

Location of plantar ulcerations in diabetic patients referred to a Department of Veterans Affairs podiatry clinic

“…These precautions, however, are not generally initiated for individuals whose ankle and pedal pulses are barely palpable (a measure of diminished vascular status). We suggest that in individuals with diabetic peripheral neuropathy and diminished vascular status, the high heel-pressure levels commonly observed [13] may result in a selective ulceration of the heel. Possibly, the techniques commonly used for the prevention of forefoot ulcerations, such as special shoes, may prevent heel ulcerations if redesigned to focus on heel-pressure reduction.…”