Effect of Partial Defect on Biomechanical Property of Tendon

Abstract

Tendon, which is a specialized connective tissue made of collagen with complex three-dimensional structures, shows variable biomechanical changes with species, age, activity levels, testing environments, testing rate, gripping technique and storage methods. This study was conducted to determine the biomechanical changes of tendon due to partial defect. Forty long flexor digitorum profundus tendons of chicken were divided into four groups, each group consisting of 10 specimens. Tension tests were performed with an Instron 1000 testing machine with various partial defects of O%(Group A), 30%(Group B), 60%(Group C) and 90%(Group D) of the longest diameter at a tension speed of 10 mm/min. Mechanical parameters, such as yielding stress, maximum stress, modulus of elasticity and total energy absorption capacity were determined. Yielding stress and maximum stress increased siginificantly in Group D (P < 0.01). Young's modulus and total energy absorption to failure (modulus of toughness) were significantly higher in Groups C and D than Groups A and B. Seven out of ten failed at the defect site in Group B while all failed at the defect site in Groups C and D. These findings suggest that partial defect more than certain proportion (30% in this study) would be better protected from vigorous activities until healing is well advanced in clinical situations. Although Young's modulus and modulus of toughness seemed to increase probably due to three dimensional cross linkage of both intact and damaged portion, absolute decrease in collagen fibril rendered failures at the defect site.