Ulnar Collateral Ligament (UCL) Injuries

An ulnar collateral ligament (UCL) injury is an inner elbow injury. It’s most commonly an overuse injury and most famously known for being a baseball pitcher’s injury. If you have a UCL injury you will feel pain and tenderness at your elbow. Treatments include rest, ice, medications and physical therapy. Tommy John Surgery uses a tendon as a replacement for the UCL.


An ulnar collateral ligament injury labeled inside a baseball player's elbow.
Repepetitive motions like overhand throwing stresses the UCL and can lead to an injury.

What is the ulnar collateral ligament (UCL)?

Your ulnar collateral ligament (UCL) is a strong band of tissue on the inner side of your elbow. It keeps your elbow joint stable during the act of throwing or overhead arm movements.

Stress on your UCL from repetitive overhead movement or a fall on your outstretched arm can irritate and inflame, stretch, partially tear or completely tear your UCL. Ligament damage leads to pain, looseness in your elbow joint and loss of function.

The UCL is the most common ligament injured from repetitive overhand throwing. It’s probably best known as the ligament most often injured in baseball pitchers.


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How does the ulnar collateral ligament work with the bones of the elbow joint?

Your elbow joint is where the ends of three bones meet — your two lower arm bones (ulna and radius) and your upper arm bone (humerus). The joint is a combination of a hinge and pivot joint. The hinge allows your arm to bend and straighten and the pivot allows your lower arm to twist and rotate.

The UCL is located on the inside of your elbow — on your pinky side. It’s made of three bands of tissue that connect your humerus to your ulna. There’s a front (anterior) band, a back (posterior) band and a diagonal (transverse) band. The anterior band is the most important for keeping your elbow stable.

How are ulnar collateral ligament (UCL) injuries classified?

There are three grades of UCL sprain injuries:

  • Grade 1: The ligament is stretched but not torn.
  • Grade 2: The ligament is stretched and might be partially torn.
  • Grade 3: The ligament is completely torn.

Symptoms and Causes

What are the symptoms of an ulnar collateral ligament injury?

Mild to moderate symptoms include:

  • Pain and tenderness on the inner side of your elbow during or after a session of overhead arm activity.
  • Pain with a fast forward movement of your arm.
  • Weak or unstable feeling at your elbow.
  • Weak or clumsy hand grip.
  • Loss of ability to throw as fast or hard.

Symptoms of a torn ligament include:

  • Feeling a sudden pop along the inside of your elbow.
  • Severe pain.
  • Loss of ability to throw.
  • Tingling and numbness in your pinky and ring fingers. This means your ulnar nerve is also pinched or injured.

What causes an ulnar collateral ligament (UCL) injury?

Overuse and trauma are the two main injuries that affect your ulnar collateral ligament (UCL).

Overuse, wear and tear injuries

Most cases of UCL damage are from overuse. Repetitive motion, like overhand throwing, stresses the ligament. Months or even years of continued strenuous use cause your UCL to stretch, become irritated and the tissue breaks down from small microtears. Your elbow joint becomes loose (“unstable”). Your UCL may become strained and inflamed, partially or completely torn, or one end of the ligament may pull away from the bone.

Traumatic injuries

Traumatic injuries to your UCL involve a blow or hit to your elbow. They are not overuse injuries. A fall with a landing on your outstretched arm “to break your fall” is one example. This can result in an elbow dislocation or fracture that can injure your UCL.


Do I lose all ability to use my arm if I have an ulnar collateral ligament (UCL) injury?

Typically even a UCL tear may not affect your daily living activities, like carrying a bag, lifting items or other non-throwing activities. However, you may not be able to take part in activities that require throwing or repetitive, strenuous overhead arm movements.

Diagnosis and Tests

How is an ulnar collateral ligament (UCL) injury diagnosed?

Your healthcare provider (usually an orthopaedic specialist or a sports medicine specialist) will review your medical and athletic history and perform a physical exam. During the exam, they’ll check your range of motion, elbow strength, elbow stability, arm muscle mass and appearance and may examine your shoulder. They’ll also ask you where you feel pain.

Tests your provider may order include:

  • Valgus stress test. This is a physical test in which your provider places their fingers on your UCL after raising your lower arm 30 degrees. They then gently push your elbow inward toward your body while pulling your lower arm outward. A positive test is a feeling of looseness at the elbow joint and pain.
  • Computed tomography (CT) and X-rays. These imaging tests show pictures of your bones, stress fractures and other bone issues that may contribute to your elbow pain and limited motion. They don’t directly show soft tissue like the UCL.
  • Magnetic resonance imaging (MRI) scan. This imaging test shows injuries to soft tissues such as tendons and ligaments. It can also show small fractures not picked up on X-rays.
  • Arthrogram. This is an MRI plus an injection of dye into your elbow joint to make hard-to-detect problems easier to see.

Management and Treatment

How is an ulnar collateral ligament (UCL) injury treated?

Treatment depends on the severity of your ulnar collateral ligament (UCL) injury and how much you want to use your arm for strenuous overhead movements or throwing activities. If you have a minor UCL tear, it may heal on its own. You may find relief from pain and discomfort from nonsurgical treatments.

Nonsurgical UCL injury treatments include:

  • Rest.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Advil®, Motrin®) and naproxen (Aleve®). Ask your provider about a prescription-strength NSAID if you need it.
  • Ice. Apply ice to your elbow daily to reduce pain and swelling.
  • Physical therapy. Begin physical therapy to strengthen the muscles around your elbow.
  • Injections of platelet-rich plasma (PRP). A small amount of your own blood is withdrawn and your platelets are separated from other blood components. The platelets are injected into the area of your injury. Injections of PRP may be helpful in those with a partial UCL tear.

Surgical treatments include:

  • UCL direct repair. If a single traumatic event caused your UCL ligament to pull off the bone, it may be possible to reattach it.
  • UCL reconstruction (Tommy John Surgery). If you have an unstable or torn UCL and nonsurgical treatments don’t provide pain relief or if you’re an athlete and want to continue throwing or engage in other strenuous overhead arm movements, your provider will recommend UCL reconstruction.

With this surgery, your surgeon takes a tendon from another area of your body or a donor. The tendon is attached to the ulna and humerus to act as the new UCL. The remaining parts of the original UCL may be attached to the new graft to strengthen it.

The goal of surgery is to restore elbow stability and range of motion, improve elbow strength and relieve pain.

Why is UCL reconstruction called Tommy John Surgery?

It’s named after the first person to undergo the procedure. Tommy John was a major league baseball pitcher who tore his UCL ligament in 1974. He sat out a season but is the first pitcher to have the surgery and successfully return to baseball.

What tendons are most commonly used as grafts for UCL reconstruction?

Grafts are typically taken from one of these tendons:

  • Hamstring tendon.
  • Palmaris longus tendon from your forearm.
  • Big toe extensor tendon.

What are the complications of UCL reconstruction surgery?

Some complications are like those you’d have with any surgery, such as the risk of infection or issues related to anesthesia.

Other complications specific to UCL reconstruction include:

  • Stretching or rupture of the new graft. In this case, a second surgery with a new graft can be done.
  • Ulnar nerve irritation. Your ulnar nerve passes around your elbow joint. Your surgeon may need to move it in front of your elbow joint to prevent further irritation.


How can I reduce my risk of an ulnar collateral ligament (UCL) injury?

Proper conditioning, proper elbow movement technique and rest when you feel elbow discomfort can help prevent ulnar collateral ligament injury.

In athletes, a pitch count limit and required rest can help protect against injury. Also, proper conditioning, stretching and strength training and proper throwing technique (avoid sidearm throwing) can help reduce the chance of UCL injury.

Outlook / Prognosis

How long does recovery take after an ulnar collateral ligament (UCL) injury?

Without surgery:

Recovery can take several weeks to several months if you have a UCL tear. Your recovery length depends on how much range of motion you wish to regain.

With UCL reconstruction:

Recovery can take nine months to a year or longer. You’ll wear a hinged brace to slowly increase your range of motion. If you plan to return to rigorous throwing activities, you’ll need a personalized physical therapy and pain management program to strengthen your elbow and improve your range of motion and function.

Living With

How can I help my student-athlete avoid overuse injuries such as ulnar collateral ligament injury?

Some tips to help reduce overuse injuries include:

  • Get a preseason physical to identify health issues that could lead to overuse injuries.
  • Learn proper throwing mechanics. Set specific pitch limits per outing.
  • Participate in a year-round physical conditioning program. Such a program will include stretching and strengthening exercises.
  • Always perform warm-up and cool-down exercises before and after athletic activities.
  • Never play or practice if injured or in pain.
  • Avoid playing the same sport all year long. Encourage your student-athlete teenager to take a season off to rest muscle groups, tendons and ligaments from constant use.

What is Little Leaguer’s elbow?

This is a condition that affects the elbow of teens. It’s an injury to the growth plates. The growth plate is on the ends of the bones that form the elbow joint. Because your teen’s bones are still growing, the growth plate is not as strong as other areas of the bone and the ligaments or tendons. Throwing puts more pressure on the weakest area — the growth plate. Repetitive throwing forces can damage tissue and bones in young athletes. If your teen pitcher says they have pain in their elbow, get it looked at by your healthcare provider, orthopaedic specialist or sports medicine specialist.

A note from Cleveland Clinic

Ulnar collateral ligament injury is an inner elbow injury. It’s mainly an overuse injury and is most famously known as a baseball pitcher’s arm injury. However, this injury can happen to anyone who repeatedly uses strenuous overhead arm movements. Symptoms include pain and tenderness at your elbow. Some might feel a sudden pop at the inner elbow. If you’re not an athlete or using repetitive overhead arm movements, your elbow might heal with simple treatments such as rest, ice, medications and physical therapy. Tommy John surgery uses a tendon from another body area or a donor as a replacement ligament. You and your healthcare provider will decide which treatments are best for you based on how severe your injury is and how much you need to use strenuous overhead arm motions.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 04/10/2022.

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