Comparative effects of monopolar radiofrequency energy and conservative management of mechanical properties of elongated lateral collateral ligament in rabbits: an experimental study.

Abstract

We examined the biomechanical effects of shrinkage in elongated rabbit lateral collateral ligament. This study was designed in an attempt to evaluate the energy effects of monopolar radiofrequency on strained but not ruptured ligaments. In treatment of ligament injuries difficulty in reducing increased laxity after trauma and recurrence of instability are important factors for failure. Ligament elongation and laxity were achieved in operating room by applying varus stress for multiple times. In Group C ( n = 8 ), elongated lateral collateral ligaments were treated only with above-knee cast, while in Group S ( n = 8 ), they were treated with shrinkage and above-knee casts. The un-operated sides were labeled as control groups. At the 12th week after surgery the animals were sacrificed and hind limbs were disarticulated. Removing the other soft tissues around knee, only lateral collateral ligaments were left intact. Biomechanical analyses of the effects of two different treatment methods were compared by performing a pulling-out test. Considering maximum load and stiffness, conservatively treated ligaments were stronger and stiffer than shrunken ligaments ( P < 0.05 ). Biomechanical values were altered by both treatment methods. Reflecting an alteration in intra-molecular structure, the main alteration was the decrease of strength in shrunken ligaments. In ligament injuries, we concluded shrinkage not to be superior to conservative treatment.