Overview
what it is and why it mattersThe ulnar collateral ligament (UCL) is the main ligament on the inner side of your elbow. Its job is to stop your elbow from bending sideways toward your body when load is applied. That sounds simple, but during the cocking phase of a baseball pitch, the inner elbow takes one of the highest forces measured in any sport, and the UCL is what keeps it together. UCL injuries run from minor sprains all the way to a complete tear. It is the defining injury of baseball pitchers, but javelin throwers, quarterbacks, and wrestlers see it too.
Diagnosis
exam first, imaging secondDiagnosis starts with the story and the exam: pain on the inner side of the elbow when throwing, a noticeable drop in velocity, and a focused physical exam of the elbow. An MRI with contrast injected into the joint (MRI arthrography) shows partial or complete UCL tears. Nerve-conduction studies are added when we want to rule out a pinched nerve as a cause, either carpal tunnel at the wrist or cubital tunnel at the elbow.
Treatment Path
how care progresses1
Rest and Activity Modification
For minor sprains, the first move is a complete throwing break for several weeks. Once the pain has settled, return to throwing follows a structured interval program: short toss before long toss, flat ground before mound work, building gradually.
2
Physical Therapy
PT focuses on three pieces: strengthening the forearm muscles that share the load with the UCL, stretching the back of the shoulder (which gets tight in throwers and shifts stress onto the elbow), and cleaning up throwing mechanics so the same forces do not keep loading the same ligament.
3
PRP Injection
An injection of platelet-rich plasma (PRP), concentrated growth factors drawn from your own blood, placed precisely at a partial UCL tear is sometimes considered after rest, activity changes, and physical therapy. The evidence in partial UCL tears is limited and mixed, and for some pitchers PRP with structured rehab may delay or avoid surgery. It is not covered by insurance (self-pay).
Surgical Options
if non-operative care isn't enoughFor competitive throwers with a complete UCL tear, or partial tears that have not responded to rehab and PRP, the answer is UCL reconstruction, popularly known as Tommy John surgery. The torn ligament is rebuilt with a tendon graft (often taken from your own forearm or hamstring) and woven through small bone tunnels at the elbow.
Frequently Asked
questions we hear in clinicWhat does the UCL actually do?
The ulnar collateral ligament is the main ligament on the inner side of the elbow. Its job is to stop the elbow from bending sideways toward the body when load is applied. During the cocking phase of a baseball pitch, the inner elbow takes one of the highest forces measured in any sport, and the UCL is what keeps it together.
Is this only a baseball injury?
No. It is the defining injury of baseball pitchers, but javelin throwers, quarterbacks, and wrestlers see it too.
How serious is a UCL injury?
UCL injuries run from minor sprains all the way to a complete tear. For minor sprains, the first move is a complete throwing break; for competitive throwers with a complete tear, the answer is reconstruction.
What is Tommy John surgery?
Tommy John surgery is the popular name for UCL reconstruction. The torn ligament is rebuilt with a tendon graft, often taken from your own forearm or hamstring, and woven through small bone tunnels at the elbow.
Will I need surgery?
Reconstruction is for competitive throwers with a complete UCL tear, or for partial tears that have not responded to rehab and PRP. Minor sprains are treated first with a complete throwing break, physical therapy, and a structured return-to-throwing program.
When can I throw again?
For minor sprains, the first move is a complete throwing break for several weeks. Once the pain has settled, return to throwing follows a structured interval program: short toss before long toss, flat ground before mound work, building gradually.
What about PRP?
PRP (platelet-rich plasma) is concentrated growth factors drawn from your own blood, placed precisely at a partial UCL tear. It is sometimes considered after rest, activity changes, and physical therapy. The evidence in partial UCL tears is limited and mixed, and for some pitchers PRP with structured rehab may delay or avoid surgery. It is not covered by insurance (self-pay).
Providers Who Treat UCL Injury
sports-medicine team
Further Reading
authoritative sourcesExternal patient-education references and related OSI pages for additional background: