Tommy John surgery, also known as ulnar collateral ligament (UCL) reconstruction, is a surgical procedure used to repair a torn UCL inside the elbow. It is named after the first baseball pitcher, Tommy John, who underwent the procedure and successfully returned to his sport. The surgery involves replacing the damaged ligament with a healthy tendon from another part of the patients body or from a cadaver. The procedure is typically performed on athletes who play sports that involve overhead throwing, such as baseball pitchers, and who have sustained a high-grade injury to the UCL. The surgery is usually an outpatient procedure performed under general anesthesia and may last anywhere from 60 to 90 minutes. The rehabilitation protocol after a Tommy John surgery typically involves three phases, and it may take overhead athletes more than a year or longer to return to their prior level of play. The success rate of the surgery is high, with return-to-play rates of 86% for all players who had reportedly undergone Tommy John surgery.