Comparison of Acute Histologic and Biomechanical Effects of Radiofrequency Ablation and Cryoablation on Periarticular Structures in a Swine Model

Abstract

PurposeTo compare the acute effects of radiofrequency (RF) ablation and cryoablation on the structural integrity of nontarget periarticular tissues that may be placed at risk during percutaneous bone ablation. Materials and MethodsRF ablation and cryoablation were separately performed on tendon, articular cartilage, and ligament in an ex vivo porcine model by using standard bone ablation protocols. Gross and histopathologic analysis was performed on cartilage and tendon (n = 6 for each treatment group, n = 5 controls). Tendon lengths were measured before and after ablation. Biomechanical tensile testing was performed on each ligament sample after ablation, with quantification of ultimate load at failure and linear stiffness (n = 7 ligaments in treatment and control groups). ResultsRF ablation and cryoablation injured chondrocytes within the ablation zones but caused minimal effects on gross and histologic cartilage architecture. Cryoablation resulted in minimal gross and histologic effects on tendon whereas RF ablation resulted in marked disruption of collagen fibers and significant longitudinal shortening (P = .002). Similarly, cryoablation did not alter ligament strength or stiffness compared with control, whereas RF ablation resulted in a significant decrease in tensile strength and stiffness compared with control and cryoablation samples (P < .001). ConclusionsNeither RF ablation nor cryoablation resulted in significant acute changes in cartilage architecture. However, RF ablation resulted in marked disruption of tendon architecture, tendon shortening, ligament weakening, and loss of ligament stiffness, whereas cryoablation had no significant effect on any of these parameters. These findings suggest that cryoablation may have fewer negative acute effects than RF ablation, although long-term outcomes are currently unknown.