The ligament that connects the bone in upper arm to the bones of the forearm gives the elbow joint stability. When it tears, a pitcher is unable to throw.

Tommy John surgery is also known as ulnar collateral ligament (UCL) reconstruction. A ligament in the pitcher’s elbow is replaced with a nonessential tendon from elsewhere in the body.

According to a 2010 study by American Sports Medicine institute, 83 percent of patients returned to the previous level of competition or higher. Although 12 to 18 months of recovery and rehabilitation are required.

diagram of Tommy-John-procedure