Stiffness of Canine Stifle Joint Ligaments at Relatively High Rates of Elongation

A falling-weight impact tester was developed specifically to evaluate the tensile characteristics of animal joints at high elongation rates. The tensile force and elongation in the ligaments of the canine stifle joint were measured using a force transducer, a linear variable displacement transducer, and a digital storage oscilloscope. Stiffness and elongation rates were determined at 1 mm and at 2 mm elongation. The stiffness was calculated as the slope of the force-elongation curve, and the elongation rate was calculated as the slope of the elongation-time curve. Results demonstrated that stiffness in the canine stifle joints was not affected by the rate of elongation in the 0.1 to 1.0 m/s range.