The Forefoot-to-Rearfoot Plantar Pressure Ratio Is Increased in Severe Diabetic Neuropathy and Can Predict Foot Ulceration
- Antonella Caselli, MD1,
- Hau Pham, DPM1,
- John M. Giurini, DPM1,
- David G. Armstrong, DPM2 and
- Aristidis Veves, MD1
- 1Joslin Beth Israel Deaconess Foot Center, Harvard Medical School, Department of Surgery, Boston, Massachusetts
- 2Southern Arizona Veterans Affairs Medical Center, Tucson, Arizona
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 = 20), mild (n = 66), moderate (n = 95), and severe (n = 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 ± 4.5 and 3.8 ± 2.7 vs. 3.0 ± 2.1 and 3.3 ± 2.1 kg/cm2 [mean ± SD], respectively; P < 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 ± 2.0 and 3.2 ± 1.9 vs. 2.5 ± 1.3 and 2.3 ± 1.0, respectively; P < 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 ± 2.4 vs. 1.5 ± 1.2, 1.3 ± 0.9, and 1.6 ± 1.0, respectively; P < 0.0001). In a logistic regression analysis, both forefoot pressure (odds ratio 1.19 [95% CI 1.11–1.28], P < 0.0001) and the F/R ratio (1.37 [1.16–1.61], P < 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.
- CPPT, cutaneous pressure perception threshold
- F/R ratio, forefoot-to-rearfoot ratio
- GRF, ground reactive force
- MTPJ, metatarsophalangeal joint
- NDS, neuropathy disability score
- OR, odds ratio
- STJ, subtalar joint
- VPT, vibration perception threshold.
Footnotes
-
Address correspondence and reprint requests to Aristidis Veves, MD, Joslin Beth Israel Deaconess Foot Center, One Deaconess Rd., Boston, MA 02215. E-mail: aveves{at}caregroup.harvard.edu.
Received for publication 13 September 2001 and accepted in revised form 13 March 2002.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
- DIABETES CARE
