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

Abstract

The biomechanical properties of plantar tissues were investigated for four older neuropathic diabetic patients and four normal younger subjects. Indentation tests were performed at four high pressure areas with three postures in each subject. The tissue thickness and effective Young's modulus were measured by an ultrasound indentation system. The system comprised a pen-size probe having an ultrasound transducer at the tip and a load cell connected in series with it. Results showed that the plantar soft tissues of the elderly diabetic patients were significantly stiffer and thinner when compared with the normal young subjects.For the diabetic subjects tested, the Young's modulus at the 1st metatarsal head was significantly larger than those at the other three sites. This site dependence was not observed in the normal young subjects. The plantar tissue became significantly stiffer in the normal young subjects as a result of posture changes. This posture dependence of the Young's modulus was not established for the elderly diabetic group.

Biomechanics of Pressure Ulcer in Body Tissues Interacting with External Forces during Locomotion

“…The tissues became stiffer with dorsi-flexion and plantar-flexion, as compared with measurements made with the ankle in neutral position (28). The plantar soft tissues for diabetic subjects were found stiffer and thinner than normal, especially around the first metatarsal head (28,30,40). Such differences were not observed in (31).…”

“…Tissue deformation was monitored either by linear variable differential transformers (LVDT) or by ultrasound. Measurements at different plantar foot regions showed a range of Young's modulus from 43kPa to 120kPa (28). The exact values depend on the site, subject group, loading speed, and range of deformation.…”

“…Measurements of the in-vivo properties of skin and the subcutaneous tissues have been reported. (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32).…”

An indentation apparatus for evaluating discomfort and pain thresholds in conjunction with mechanical properties of foot tissue in vivo

“…These properties are also the basis for the development of finite element models of feet [5][6][7][8][9][10]. In clinical settings, tissue assessments are predominantly performed through palpation [11], even though such evaluations are inherently subjective and rely on observer experiences [12].…”

Clinical and Radiographic Predictors of Scoliosis in Patients with Myelomeningocele

“…Most investigators have used radiography to study the structure of the foot in diabetic patients; ultrasound has been used only recently 29,30,[34][35][36][37][38] . The limitations of planar studies (radiography and ultrasound) are that they do not allow a unified structural assessment.…”