Extensor Carpi Ulnaris Instability

ExitCare ImageInjury to the extensor carpi ulnaris (ECU) tendon of the wrist may result in ECU instability. In this condition, the ECU is displaced from its normal spot on the little finger side (ulnar side) of the back of the wrist. The ECU tendon attaches the ECU muscle to the bone. The ECU straightens and rotates (abducts) the wrist. The ECU is important for gripping and pulling. Normally, the ECU tendon slides in a grove over the forearm, on the little finger side. A ligament-like structure (retinaculum) holds it in place. Damage to the retinaculum causes the ECU tendon to slip in and out of the groove (sublux) or to completely come out of the groove (dislocate).


  • Painful "snapping" feeling over the back of the wrist, on the little finger side. Usually, when turning the palm up or down.

  • Inflammation or bruising at the injury site (uncommon).

  • Often, few or no symptoms.


  • This is often an overuse injury. It is caused by repetitive and excessive turning of the palm upward. Also, forceful turning up of the palm, sometimes while bending toward the little finger, may be a cause.

  • Birth defect (congenital abnormality), such as shallow or malformed groove for the tendons.


  • Sports that cause repeated, forceful turning up of the palm (i.e. tennis, golf, rodeo riding, weightlifting, football).

  • Previous wrist injury or restraint.

  • Poor wrist strength and flexibility.


  • Warm up and stretch properly before activity.

  • Maintain physical fitness:

  • Hand, wrist, and forearm strength.

  • Flexibility and endurance.

  • Cardiovascular fitness.

  • When playing high risk sports, protect the wrist with supportive devices (wrapped elastic bandages, tape, braces).

  • Full recovery must be complete, before returning to practice or competition.


Some people may have no symptoms or limitations and do not need treatment. However, if ECU instability causes chronic pain and impairment, full recovery can be expected with proper treatment. Surgery may be needed to stop partial dislocations (subluxations). Returning to sports may take 6 to 9 months.


  • Chronic pain, impairment, and recurring full or partial dislocation.

  • Tearing of the tendon, due to friction wear from recurring full or partial dislocation.

  • Wrist weakness.

  • Prolonged impairment.


Treatment first involves the use of ice and medicine, to reduce pain and inflammation. Also, raising the injured wrist to a level above the heart helps. A brace, splint, or taping may be advised to reduce pain during activity. If non-surgical treatment does not work, surgery is often advised, to repair the retinaculum, tendon lining (tendon sheath), tendon, or to replace the tendon (reconstruction), if the tendon is torn. After restraint (with or without surgery), stretching and strengthening exercises are needed. Exercises may be performed at home or with a therapist.


  • If pain medicine is needed, nonsteroidal anti-inflammatory medicines (aspirin and ibuprofen), or other minor pain relievers (acetaminophen), are often advised.

  • Do not take pain medicine for 7 days before surgery.

  • Prescription pain relievers are usually prescribed only after surgery. Use only as directed and only as much as needed.


Cold treatment (icing) relieves pain and reduces inflammation. Cold treatment should be applied for 10 to 15 minutes every 2 to 3 hours, and immediately after activity that aggravates your symptoms. Use ice packs or an ice massage.


  • Pain, tenderness, or swelling gets worse, despite treatment.

  • You experience pain, numbness, or coldness. Blue, gray, or dark color appears in the fingernails.

  • Any of the following occur after surgery:

  • Signs of infection: fever, increased pain, swelling, redness, drainage of fluids, or bleeding in the affected area.

  • New, unexplained symptoms develop. (Drugs used in treatment may produce side effects.)