Answer:
Tommy John surgery repair the ulnar collateral ligament.
Explanation:
Tommy John surgery is the reconstruction of a torn ulnar collateral ligament which is located on the inner side the elbow that holds or support the elbow joint. The purpose of the surgery is to eliminate pain and stabilize the elbow and restore the range of motion. This surgery is often given to players that excessively uses the elbow and the first to undergo this procedure was Tommy John, a baseball pitcher in 1974.