Medial UCL reconstruction 

The ulnar collateral ligament (UCL) is inside the elbow. It connects the bone of the upper arm to a bone in the forearm. Repetitive motions like throwing put a lot of stress on the UCL. This can cause it to tear or become seriously injured.

If this happens, the Tommy John surgery can help. A surgeon replaces the damaged ligament with a tendon from another part of the patient’s body. The surgery was first done in 1974 on baseball pitcher Tommy John.