Thermal Epiphysiodesis Made with Radio Frequency Ablation: An Alternative Treatment for Leg Length Discrepancy Shiguetomi-Medina JM, Rahbek O, Stødkilde-Jørgensen H, Møller-Madsen B Introduction Anisomelia is a condition of leg length discrepancy. It is often treated with epiphysiodesis of the growth plate to inhibit growth. Epiphysiodesis has become the most commonly used procedure for leg length equalization. Current techniques involve opening cortical windows, usage of staples or tension devices, and destruction with curettes or drills. Complications such as breaching of the cortex, damage to the metaphysis, and vascular or nerve injury have potentially serious consequences. Therefore, there is a need for a reliable and precise procedure which overcomes the complications. Radiofrequency ablation involves the application of energy in the radio wave frequency resulting in local thermal coagulative necrosis. It has been shown to be a reliable technique for creating thermally induced coagulation necrosis. The experience with this technique has been reported as a clinical success and complications are rare. Objective: Development of a new technique for epiphysiodesis using radiofrequency ablation in an experimental porcine model. Methods Six 35 kg pigs and two 25 kg non-mature pigs were used. A control leg was randomly selected and the contralateral treated at two ablation sites (lateral and medial) identified at the proximal tibia growth plate using x-ray. Under general anesthesia, a probe was inserted and the ablation performed. T1, T2 and water content MR images were performed right after the procedure, 12 weeks later for 6 animals, and 6 months later for the last 2 ones. The length of both tibiae was measured immediately after the ablation and at the end of the study. Results Both legs were equal at the beginning of the study and, overall, there was a leg length difference (P=0.006) in average of 4.8mm (SD=2.25, Median=3.88) at the end. For the 12 week follow-up we found an average leg length difference of 3.9mm (SD=1.286, Median=3.666, P=0.014), and for the 6 month one we found a difference of 8.11mm in average. No damage to the surrounding cartilage structures was found. The animals could walk normally after the anesthesia and no signs of pain or discomfort were presented during the follow-up period. Discussion and Conclusion Epiphysiodesis using radio frequency ablation is an innovative technique that may represent an alternative way of treatment that potentially involves less scarring, less exposure to X-rays, and reduces the risk of injuring the surrounding structures compared to current methods. These results show that this technique can arrest growth in a safe and effective way. However, longer studies must be performed to obtain more evidence of both the safety and effectiveness of the procedure.