The Mannequin-leg: a new instrument to assess stiffness of compression materials

Stiffness of compression material, which has major impact on the performance of the used product, has mainly been investigated by clinical in vivo experiments up to now. Experimental two-centre study has been performed in Japan and in Austria. Results are presented using a novel leg model, whose circumference can mechanically be extended by 1 cm. The change of the interface pressure measured under a compression device corresponds to its stiffness. Inelastic and multi-component bandages show stiffness values which are more than three times higher than those of elastic bandages and of compression stockings. There is a significant correlation between the stiffness values measured with the simple mannequin- leg and those obtained from extensometer measurements (Hohen stein-method) on one hand, and also with data on the human leg (static stiffness index) on the other hand. The average variation coefficient with repeated measurements is 5.4%. The absolute values differ with the used pressure probes. The newly developed mannequin-leg offers a simple method to measure and to compare the stiffness of compression stockings and bandages, including the combination of such devices.