Abstract
This paper deals with the attenuation of impact load through patella-patellar tendon-tibial tuberosity (PTT) complex with respect to the progress of ossification of growing cartilage in tibial tuberosity. Materials used in this study were PTT complexes and patellar tendons taken from porcine hind legs with three different stages of ossification of tibial tuberosity. Their stages of ossification were represented by body weight (20, 100, and 200kgf). Impact tensile tests on PTT complexes and patellar tendons were performed at room temperature using the split-Hopkinson pressure bar technique. In both tests on PTT and patellar tendons, pretensile loads were applied to them just before an application of impact load. The experimental load transmission ratio of PTT complexes increased with an increase of pretension, independent of body weight. Larger body weight, or highly ossified PTT complex appeared to show lower load transmission ratio. Significant change in Young's modulus of patellar tendon with an increase of pretension as well as the progress of ossification of growing cartilage in tibial tuberosity was not found. Impact response analyses were also performed for the prediction of load transmission ratio as well as the section subjected to maximum strain in PTT complexes with different stages of ossification based on the one-dimensional wave propagation theory. The results obtained from the dynamic analyses well corresponded to the location of injuries in different stages of growing process, while static analyses could not predict such clinical situation.
