Tommy John surgery, known by doctors as ulnar collateral ligament reconstruction (or UCL), 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 players 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.
After the tendon from the forearm of the opposite elbow or below the knee is harvested it is then woven in a figure-eight pattern through tunnels that have been drilled in the ulna and humerus bone that are part of the elbow joint.