Ulnar Collateral Ligament (UCL) Injury

What is the UCL?
The UCL is a key ligament on the inner side of the elbow that stabilizes it during throwing and overhead motions.
What is This Condition?
A UCL injury occurs when the ligament is stretched or torn. It is especially common in throwing athletes such as baseball pitchers.
What are the Symptoms?
Pain on the inner side of the elbow during throwing
A “pop” or sudden pain at the time of injury in some cases
Loss of throwing velocity or control
Weakness or instability when the elbow is stressed
Swelling or bruising after an acute tear
What Causes It?
Repetitive overhead throwing, especially with poor mechanics or overuse
Sudden injury from a forceful throw or collision
Chronic stress from sports like baseball, javelin, or gymnastics
How is It Diagnosed?
Exam: tenderness along the inner elbow, pain with valgus stress testing
MRI (with or without contrast): shows ligament damage
Ultrasound: sometimes used dynamically during stress testing
How is It Treated?
Non-surgical:
Rest, activity modification, and anti-inflammatories
Physical therapy to strengthen the forearm, shoulder, and core
Pitching mechanics evaluation for athletes
Surgical:
UCL reconstruction (“Tommy John surgery”): ligament is replaced with a tendon graft
UCL repair with internal brace: an option for certain types of tears, especially in younger athletes
Learn more from AAOS (OrthoInfo):
https://orthoinfo.aaos.org/en/diseases--conditions/ulnar-collateral-ligament-ucl-injury/
