Thermal modification of tissues in orthopedics targets type I collagen. Under an appropriate amount of heat stress, intramolecular bonds are broken, leading to an uncoiling of the triple-helix collagen molecule. With careful control of mechanical forces during the postoperative period, a permanent “shrinking” of the tissues can be achieved. Thermal modification of tissues to treat joint instability has been used with promising results in the shoulder. More recently, this technology has been applied to treating patients with chronic lateral ankle instability. Between February 1999 and December 2001, 42 patients were treated with thermal-assisted capsular modification for chronic ankle instability using a bipolar radiofrequency, end-effect thermal control wand. At an average follow-up of 14 months, there was a significant pre- to postoperative difference in the modified AOFAS hindfoot score and the physical component of the SF-12. There has been no revisional surgery. Based on the authors' experience, they think that thermal modification of tissues can be applied to patients who have failed conservative treatment of chronic lateral ankle instability.