Thermal effects after anterior cruciate ligament shrinkage using radiofrequency technology: a porcine cadaver study.

The effects of thermal energy on an anterior cruciate ligament (ACL) are unknown. This study was undertaken to know the immediate and direct effects of thermocoagulation on normal ACL. Thermocoagulation was generated by monopolar radiofrequency (RF) at 67 degrees C and 40 W of energy and applied with use of a commercial jig in a porcine cadaveric model, and biomechanical and histological changes were evaluated immediately. Thermocoagulation caused significant shrinkage of ACL without immediate effects on ligament biomechanical properties, including stiffness and maximal failure force. However, histological analysis demonstrated a decrease in number of dense elongated cells and blood vessels within the epiligamentous tissue, loss of areolar spaces, decrement in the periodicity of collagen waveform, and shortening and pyknotic nuclear changes of cells within the fascicular region. RF-generated thermocoagulation resulted in ACL shortening with significant changes on histological findings but not on initial biomechanical properties.