Pie-crusting of ligaments

Abstract

This project sought to investigate the effect of number of stabs for pie-crusting on the tensile properties of the bone-ligament-bone complex. Chicken femur-medial collateral ligament-tibia complexes were used for the investigation. As part of total knee replacement surgery, soft-tissue balancing is very crucial especially in operations on osteoarthritic knees. A pie-crusting technique that involves multiple stab incisions on a ligament is currently utilized. However, the effect of pie-crusting on medial collateral ligament (MCL) remains controversial and unclear and may be technique dependent. Being an important parameter when performing pie-crusting technique, it was found that the increasing number of stabs degrades ultimate tensile strength (UTS), elastic modulus and toughness. Strain at UTS also increases. However, these results can only be confirmed with more tests with larger numbers of stabs. In addition, different failure mechanisms were observed in the experiment, failure mode tends to shift from failure at ligament insertion to failure at ligament substance as the number of stabs increases.