Biomechanical Analysis of Patellar Tendon Allografts as a Function of Donor Age

We evaluated the biomechanical properties of patellar tendon allografts from donors aged 18 to 55 years. Bone-patellar tendon-bone complexes were harvested from acceptable donors and processed. Fat and soft tissue were removed, and the tendons were sectioned lengthwise leaving the central third. Area measure ments were taken, and mechanical testing was per formed. Specimens were pulled to failure at a rate of 10% of the initial length per second. The force at failure, tensile stress, modulus of elasticity, and percent elon gation were determined for each specimen. There was no significant correlation (P > 0.05) between age and any of the mechanical properties. Load at failure ranged from 2110 to 4650 N, with a mean of 3424 N. Regres sion analysis showed slightly decreasing tensile stress with increasing age, but the correlation was not signifi cant. It appears that patellar tendon allografts from do nors up to age 55 have similar mechanical properties.