Acute or chronic disruption of the ulnar collateral ligament result in medial elbow pain, valgus instability, and impaired throwing performance.

[4] Gridiron football, racquet sports, ice hockey and water polo players have also been treated for damage to the UCL.

[5][6] Specific overhead movements like those that occur during baseball pitching, tennis serving or volleyball spiking increase the risk of UCL injury.

[7] During the cocking phase of pitching, the shoulder is horizontally abducted, externally rotated and the elbow is flexed.

During the overhead throwing motion, valgus stress on the medial elbow occurs during arm cocking and acceleration.

[citation needed] Poor mechanics along with high repetition of these overhead movements can cause irritation, microtears or ruptures of the UCL.

In most cases, a physician will diagnose an ulnar collateral ligament injury using a patient’s medical history and a physical examination that includes a valgus stress test.

[citation needed] A slow and chronic deterioration of the ulnar collateral ligament can be due to repetitive stress acting on the ulna.

The repetitive stress placed on the ulna causes microtears in the ligament resulting in the loss of structural integrity over time.

[18] First a course of RICE (Rest, ice, compression, elevation) is typically coupled with NSAIDS (Non-steroidal anti-inflammatory drugs) to help alleviate pain and swelling.

When the swelling has subsided, individual exercises or physical therapy may be prescribed to strengthen muscles around the elbow joint to compensate for tearing in the UCL.

[20] Surgical treatment may help restore the ability to perform the overhand throwing motions most commonly associated with UCL injuries.

The rehab program should include proprioceptive exercises to stimulate mechanoreceptors as well as arm strengthening, emphasizing proximal scapular stabilization.

[24] Post-operative treatment is related to the restoration of normal scapulohumeral rhythm, which begins with establishing trunk stability, elbow range of motion and strength as well as balance exercises.

In order to combat the rumors, physicians were motivated to educate the public that Tommy John surgeries are only for those who have severe UCL injuries.

[26] According to the International Classification of Diseases, 9th Revision, Clinical Modification, ICD-9-CM, in 2008 the U.S. listed the diagnosis code for UCL injury as 841.1: Sprain ulnar collateral ligament.