The use of thermal energy in the shoulder to tighten capsular tissues through collagen denaturation is well established. Although reported complication rates are low, the natural history of thermal manipulation to both target and collateral tissue is poorly defined. We report two cases of biceps tendon rupture after arthroscopic capsular shrinkage. Both patients were young, athletic men with normal long head biceps tendons at the time of surgery. Each patient experienced a complete tear of the long head with distal muscle retraction, resulting in a "Popeye" deformity, at 3 months postoperatively. One patient elected further surgery with biceps tenodesis. Both patients have returned to their athletic activities with minimal functional deficits.