The Effect of Radiofrequency Energy-Induced Thermal Shrinkage on Anterior Cruciate Ligament: An in Vitro Biomechanical Study Using a Rabbit Model

ABSTRACT

Recently, devices using radiofrequency energy have been developed for arthroscopic soft tissue ablation and shrinkage. The purpose of this study was to evaluate effect of radiofrequency energy on the biomechanical competence of thermal shrinkage of anterior cruciate ligament and was to demonstrate a new approach for radiofrequency energy, applying to ligamentous tissue in a dynamic fashion. Twelve New Zealand White rabbits, were divided into two experimental groups by right and left hindlimbs. Thermal shrinkage of the anterior cruciate ligament of rabbits produced using radiofrequency energy generator(N=12, group I). And untreated control group(N=12, group II). The percent shrinkage was calculated from the change of length of anterior cruciate ligament after radiofrequency energyinduced thermal shrinkage. The maximal tensile stress and linear stiffness of anterior cruciate ligament as biomechanical competence were assessed. The results obtained were as follows 1. In the group I the percentage of shrinkage was 29.50Fo on the average. 2. The average of maximal tensile stress to failure was 271.24 kN in group I and 283.50 kN in group II. There was no significant difference(p=0.24) in the maximal tensile stress between two groups. 3. The average of linear stiffness in group I(179.16kN/mm) was higher than that of group II(148.20kN/mm). But there was no significant difference(p=0.078) between two groups. This study shows that radiofrequency energy appears to be safe to use on therma1 shrinkage of anterior cruciate ligament, which necessitate a mechanical tensile strength.