Tommy John surgery, known by doctors as ulnar collateral ligament reconstruction (UCL), is a surgical procedure in which a ligament in the medial elbow is replaced with a ligament from elsewhere in the body, often from the forearm, hamstring, knee or foot of the patient.

Tommy John surgery, known by doctors as ulnar collateral ligament reconstruction (UCL), is a surgical procedure in which a ligament in the medial elbow is replaced with a ligament from elsewhere in the body, often from the forearm, hamstring, knee or foot of the patient.

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.

Chances of a complete recovery after surgery are estimated today at 85 to 90 percent. At the time of Tommy John's operation, Jobe put his odds at 1 in 100. After his surgery in 1974, John spent 18 months rehabilitating his arm, returned for the 1976 season, and went on to pitch in the major leagues until 1989 at age 46.

Today, the procedure takes about an hour. Full rehabilitation takes about a year for pitchers and about six months for position players. Usually, pitchers who have the surgery can get their full range of motion back after about two months and can start doing weight exercises. For the next four months, they can increase the weight that they use and start doing exercises that emphasizes all parts of their arm. After six months, they can begin a throwing program.

It is not uncommon today for pitchers to throw harder after the surgery than they did before the injury that caused the surgery to be necessary. However, this results not because of the surgery itself, but from the rigorous rehabilitation that ensues following surgery.

Today, the injury and eventual surgery are becoming more common in children ranging from 10-18 due to increased season length and the more frequent use of breaking pitches by young pitchers.

A torn elbow ligament — the most common cause of what was simply called "dead arm injury" during most of the 20th century — can be caused by a number of things, but the injury is most common in pitchers and the most frequent cause is throwing too hard or overwork.