The anterior bundle of the ulnar collateral ligament is the elbow’s primary restraint against valgus force during overhead motions such as throwing. During the late cocking and early acceleration phases of the throwing motion, there are large tensile forces across the medial aspect of the elbow. With each throw, the ligament works to resist these forces and stabilize the joint.
While occasionally injuries to the ulnar collateral ligament occur acutely – meaning torn in a traumatic event with no underlying history of ligament damage – far more often they gradually fail over time. The pitcher often remembers the one throw during which the UCL finally gave way. But the ligament – and the pitcher’s performance – usually has been slowly worsening for months or even years.
Surgery for ulnar collateral ligament injuries almost always involves UCL reconstruction. A ligament from another part of the body – usually the palmaris longus tendon in the opposite wrist – is placed into the elbow to make a new ligament. The graft is passed through drill holes in both the humerus and the ulna. It is held in place by tying it to itself in a figure-of-eight fashion or anchoring it in other ways.
Studies show that roughly 83% of pitchers return to the same or higher level of pitching after surgery. It is believed that 25% of current MLB pitchers have undergone Tommy John surgery.
Unfortunately, these injuries, which used to be seen exclusively in older professional pitchers, are now being found in more high school pitchers than ever before.
In my new book, That’s Gotta Hurt: The Injuries That Changed Sports Forever, I discuss Tommy John surgery and how it has grown along with an epidemic of injuries at the youth level. If you have kids who play baseball or other youth sports, you should read it and take steps to keep your kids healthy. Click here to get your copy and get hundreds of dollars of bonus content – FREE!
Please remember, while I appreciate your questions, I cannot and will not offer specific medical advice by email, online, on my show, or in the comments at the end of these posts. My responses are meant to provide general medical information and education. Please consult your physician or health care provider for your specific medical concerns.