The tensile properties of collagen fascicles harvested from regenerated and residual tissues in the patellar tendon after removal of the central third.

The central one-third portion of the patellar tendon (PT) is commonly used for the reconstruction of the anterior cruciate ligament. For better understanding of the healing mechanisms of the PT, tensile properties of collagen fascicles harvested from the healing PT were studied. A rectangular defect was made at the central third portion in each right PT in the skeletally mature rabbit. At 6 and 12 weeks, tensile tests were performed on fascicles from the tissue regenerated in the defect and the non-resected, residual tissue. The elastic modulus and tensile strength of fascicles from the regenerated tissue gradually increased in a fashion similar to the bulk regenerated tissue. The properties of fascicles from the residual tissue were similar to those from normal tendons, which was very much different from those of the bulk residual tissue that were greatly deteriorated by the removal of the central portion.