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.
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.
Initial MFT was higher in the patients without PVD (28.2 ± 2.9°C, mean ± SD) than in patients with PVD (25.6 ± 1.9°C, P < 0.001) and in nondiabetic control subjects (25.7 ± 2.1°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°C) than in the 38 feet of the 19 survivors in this group (27.8 ± 2.3°C, P < 0.01). Only one patient with PVD developed a plantar ulcer, although four required foot surgery for ischemie feet.
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 ischemie foot disease.
