Measurement of skin elasticity on the foot

Background/purpose: The Cutometer® 580 MPA is a device that is designed to measure the viscoelastic properties of skin in response to the application of negative pressure. The aim of this study was to test the Cutometer® 580 MPA for the repeatable, quantitative measurement of the specific indices of elasticity of pedal skin. The device was used to measure and compare these indices at weight-bearing and non-weight-bearing skin sites on the foot. Methods: The relationship between the pressure application and skin displacement was determined. The inter- and intra-tester repeatability was tested. These series of experiments were conducted on 20 individuals. Data were then collected from a group of 87 healthy people for the measurement of elasticity, viscoelasticity and plasticity on several sites on the foot. The possible influences of physiological variables such as age and sex on the indices of elasticity were analysed. Results: The Hookian elastic behaviour of the skin was confirmed. The pressure application did not remain constant during the collection of displacement data, resulting in an error in these readings of between 1.71% and 3.73%. Intra-tester and variability was minimal (CV<7%). The elasticity, viscoelasticity and plasticity indices were significantly greater (P<0.001) in dorsal skin compared with skin from medial longitudinal arch (MLA) and plantar aspect of the third metatarsophalangeal joint (PMA) sites. There was a negative correlation between age and elasticity on the dorsum and MLA skin sites (r=−0.216 and −0.261, respectively). Female skin exhibited greater plasticity than male skin on all three sites on the foot (P<0.05). Conclusion: Under well-controlled conditions, the Cutometer® 580 MPA has the ability to measure accurately the viscoelastic properties of pedal skin. Such non-invasive measurements may be useful for the evaluation of changes in the skin in response to therapeutic interventions and for monitoring the progression of dermatological conditions associated with the foot.