Microstructurally based model analysis of gamma-irradiated tendon allografts.

A mathematical model of the collagenous microstructure of tendon was used to analyze the mechanical responses of gamma-irradiated patellar tendon allografts and nonirradiated controls. The model was fit to tensile test response curves from 10 pairs of allografts. Donors ranged in age from 16-64 years (six males, four females). The model indicated a decrease in elastic modulus of irradiated tendon collagen. It also suggested a significant increase in the degree and range of collagen fiber crimping following gamma irradiation. The model results agree with the literature and histological observations. The model fit the experimental response curves well and provided a structurally based, objective method of quantitatively studying the mechanical response of tendons and the consequences of irradiation sterilization.