Causes of ECU Tendon Problems

Ulnar tendon pain can have a number of causes, including ECU tendonitis and ECU tendon subluxation.

ECU stands for the extensor carpi ulnaris tendon, one of the major wrist tendons, located on the ulnar side of the wrist, which is the same side as the small finger. The ECU tendon starts on the back of the forearm and crosses the wrist joint directly on the side.

This article discusses the causes, symptoms, and treatment of ECU tendon problems.

Understanding Wrist Tendons

Tendons are fibrous connective tissue (similar to rope) that attaches muscles to bone. There are a total of six tendons that run through your forearm and control movement in your hands, wrists, and fingers.

The ECU tendon travels along the back forearm, through a groove in the ulna (forearm bone), and attaches to the base of the hand bones. It works with two other tendons to straighten the wrist and move the wrist in the direction of the pinky rather than the thumb.

ECU Tendonitis

ECU tendonitis is the result of inflammation of the ECU tendon. This condition is most common in nonathletes and generally occurs without an obvious cause. Sometimes people with ECU tendonitis have symptoms that occur following a traumatic injury, such as a wrist fracture.

Symptoms

ECU tendonitis symptoms may include:

• Tenderness directly over the ECU tendon
• Swelling or fullness of the tendon sheath
• Crepitus (a grating sound or sensation) with movement of the wrist
• Pain with resisted ulnar deviation (pointing the wrist to the pinky side)

Diagnosis

Tests are generally performed to evaluate for other sources of wrist pain. X-rays would be normal for most patients with tendonitis. Magnetic resonance imaging (MRI) might show some fluid around the tendon.

Sometimes your healthcare provider will perform a test by injecting a numbing medication (lidocaine) around the tendon to see if the pain resolves.

Treatment

Typical treatments include rest, ice application, anti-inflammatory medications, and the use of a wrist splint. If symptoms persist after these treatments, a cortisone injection may be helpful.

Seldom is a surgical procedure needed to treat ECU tendonitis, but if symptoms persist despite appropriate management, surgical debridement of the tendon can be considered.

ECU Snapping or Subluxation

Normally, the ECU tendon runs within a smooth sheath along a groove on the side of the wrist joint. It's held in this position by a ligament. Snapping ECU syndrome is a condition in which the ECU tendon slides in and out of its groove on the side of the wrist.

Snapping ECU is more likely to occur in sporting activities, such as golf and tennis, and generally follows a traumatic injury, such as a wrist fracture. The injury can cause damage to the tendon sheath and allows the tendon to slide out of its normal position. If the ECU tendon is not held in place, it may "snap" over the bone as the wrist is rotated.

Symptoms

Typical ECU subluxation symptoms include:

• Painful snapping of the wrist with twisting movements
• Tendon snapping out of its groove with turning the hand to a palm-up position
• Tendon snaps back into place when the hand is turned palm down

Diagnosis

Subluxation of the ECU tendon may be visible to your healthcare provider when doing the physical examination. Touching and moving the joint may also identify the injury.

Sometimes MRI or ultrasound imaging is used to determine the full extent of the injury to the sheath.

Treatment

Initial treatment involves splinting or casting the wrist with the tendon in its proper position to immobilize the tendon and allow the sheath to heal. 

If immobilizing isn't effective, surgical reconstruction of the tendon sheath may be required to get the tendon placed in its proper position and then placed in a cast to allow it to heal.

Summary

Two causes of ulna tendon pain are ECU tendonitis and ECU tendon subluxation. These conditions are usually treated with rest, icing, and immobilizing the wrist and tendon. If those treatments don't work, a cortisone injection (for tendonitis) or surgery may be considered.

A Word From Verywell

If you are experiencing pain in your wrist that doesn't go away, talk to a healthcare provider who can help you determine the cause of the pain and recommend the best treatment options for you.