Biomechanical assessment of plantar foot tissue in diabetic patients usingan ultrasound indentation system

The biomechanical properties of plantar tissues were investigated for four older nenropathic diabetic patients and four healthy younger subjects. Inde ntation tests were performed at four high-pressure areas with three posture s in each subject. The tissue thickness and effective Young's modulus were measured by an ultrasound (US) indentation system. The system comprised a p en-size probe having a US transducer at the tip and a load cell connected i n series with it. Results showed that the plantar soft tissues of the elder ly diabetic patients were significantly stiffer and thinner when compared w ith the healthy young subjects, For the diabetic subjects tested, the Young 's modulus at the Ist metatarsal head was significantly larger than those a t the other three sites. This site-dependence was not observed in the healt hy young subjects, The plantar tissue became significantly stiffer in the h ealthy young subjects as a result of posture changes. This posture-dependen ce of the Young's modulus was not established for the elderly diabetic grou p. (C) 2000 World Federation for Ultrasound in Medicine & Biology.