Diabetes Care, Vol 17, Issue 8 835-839, Copyright © 1994 by American Diabetes Association
The prediction of diabetic neuropathic plantar foot ulceration by liquid-crystal contact thermography
SJ Benbow, AW Chan, DR Bowsher, G Williams and IA Macfarlane
Department of Medicine, University of Liverpool, U.K.
OBJECTIVE--To assess whether the development of plantar foot ulceration
could be predicted from the mean plantar foot temperature (MFT), as
assessed by liquid-crystal contact thermography (LCT), in patients with
peripheral neuropathy. RESEARCH DESIGN AND METHODS--Fifty patients with
painful diabetic sensorimotor neuropathy were studied prospectively.
Initially, 30 patients had no significant peripheral vascular disease (PVD)
(ankle:brachial systolic blood pressure ratio > 1.0). LCT was used to
assess the MFT from eight standard plantar sites. RESULTS--Initial MFT was
higher in the patients without PVD (28.2 +/- 2.9 degrees C, mean +/- SD)
than in patients with PVD (25.6 +/- 1.9 degrees C, P < 0.001) and in
nondiabetic control subjects (25.7 +/- 2.1 degrees C, P < 0.001). At
review, on average 3.6 (range 3.0-4.1) years later, 11 patients had died (6
of whom had PVD), and one was lost to follow-up. Six patients (seven feet)
from the group without PVD had developed neuropathic plantar foot ulcers.
The initial MFT was significantly higher in these seven feet (30.5 +/- 2.6
degrees C) than in the 38 feet of the 19 survivors in this group (27.8 +/-
2.3 degrees C, P < 0.01). Only one patient with PVD developed a plantar
ulcer, although four required foot surgery for ischemic feet.
CONCLUSIONS--LCT is a simple, inexpensive, and noninvasive method of
identifying the neuropathic foot at increased risk of ulceration. Patients
with high plantar foot temperatures are at increased risk of neuropathic
foot ulceration. A normal or low MFT in the neuropathic foot is a marker of
PVD, which confers an increased risk of ischemic foot disease.