Biomechanical properties of elastase treated palmar aponeuroses

Human palmar aponeurosis was treated with elastase in the presence or absence of soybean trypsin inhibitor. The removal of elastic fibers was complete as proved by electron microscopy. Cyclic loading was performed at a constant strain rate. Residual strain was measured and the stiffness and the fraction of dissipated energy of strain energy was calculated and compared to that of untreated samples of palmar aponeurosis. Residual strain and dissipated energy showed a dramatic increase after enzyme treatment, both in presence and absence of soybean trypsin inhibitor. Stiffness, on the other hand was reduced. The remaining collagen fibers show a more viscous behavior. Our results support the hypothesis that the elastin fibers are responsible for the elastic recovery, observed on specimens of untreated palmar aponeurosis.