Tommy John surgery, known in medical practice as ulnar collateral ligament (UCL) reconstruction, is a surgical procedure in which a ligament in the medial elbow is replaced with a tendon from elsewhere in the body (often from the forearm, hamstring, knee, or foot of the patient). The procedure is common among collegiate and professional athletes in several sports, most notably baseball. The surgery is named after Tommy John, a pitcher for the Los Angeles Dodgers who was the first professional athlete to successfully undergo the operation in 1974. The procedure was performed by Dr. Frank Jobe.