The elbow joint is stabilized by strong soft tissue attachments called collateral ligaments, one of which is the ulnar collateral ligament (UCL). It is located on the medial side of the joint and may become stretched or torn resulting in pain and instability on the inner side of the elbow.

This injury often occurs in throwing athletes, like pitchers, who create tremendous amounts of stress across the joint. The collateral ligaments of your elbow are soft tissue and therefore an x-ray may not show any damage. However, Magnetic Resonance Imaging (MRI) allows physicians to diagnose fraying or tears in ligaments. Non-operative treatment consists of strengthening exercises and activity modification. Surgical intervention usually involves reconstructing the ligament, a procedure often called "Tommy John" surgery after the first baseball pitcher to have undergone the surgery. A tendon from somewhere else in the boy (often from the forearm) replaces the UCL and restores elbow stability and eliminates the associated pain. Initially, you will be placed in a splint. Thereafter, your rehabilitation will be dictated by the findings at your follow-up clinic visit, but usually involves gentle range-of-motion and eventually progresses to strengthening exercises. Full rehabilitation may take up to one year.