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What is Ulnar Carpal Instability?

Ulnar Carpal Instability is a condition in which the normal mechanics of the wrist are disrupted due to misalignment of the three bones on the pinky side of the wrist (the ulna, lunate and triquetrum) due to a ligament injury.

Falling on an outstretched hand with a twisting motion causes this injury to the many ligaments on the medial side of the wrist. If a patient has an accident where they have hurt their wrist, it is important to seek medical attention by a specialized surgeon who can accurately diagnose and treat conditions like ulnar carpal instability before it becomes more serious.

Signs and Symptoms of Ulnar Carpal Instability

Ulnar Carpal Instability manifests itself in chronic pain, stiffness, weakness and a possible clicking noise in the ulnar aspect of the wrist.

This instability is due to ruptured or weakened ligaments and can occur between the carpus and the ulna, possibly including the triquetrohamate joint or the lunate-triquetral joint.

Some of the most commonly reported symptoms of ulnar carpal instability include:

  • Bony misalignment that may or may not be painful
  • Wrist not performing correctly/giving away
  • Clicking sound or pain when the wrist is moved ulnarly from flexion to extension with axial load

Causes of Ulnar Carpal Instability

Carpal instability occurs when the carpal bones are out of position or easily moved from their normal resting position. This may be a result of chronic ligament weakening from arthritis or ligament injury from a fall, causing misalignment of the carpal bones and ulna. Collision sports, BMX, and skateboarding (full pipes more than street courses) are often implicated as causes for this injury.

Common causes and coexisting injuries with ulnar carpal instability include:

Injuries Associated with Ulnar Carpal Instability

Carpal instability can be the result of acute trauma and is often associated with other fractures to the hand and wrist area. These injuries commonly occur in the younger population as a result of more frequent falls and impacts.

There are two types of ulnar carpal instability, each requiring a proper diagnosis to try to prevent further injury from occurring.

  • Dynamic instability: Dynamic instability is an incomplete injury where the wrist maintains normal alignment at rest but subluxates under an applied load.
  • Static Instability: Static Instability occurs in complete injury to the structure with abnormal intercarpal alignment.

Additionally, this injury is associated with other fractures and injuries to the hand and wrist. These include:

  • Midcarpal instability
  • Ulnar lunate-triquetral ligament tear
  • Ulnar styloid fracture
  • Lunotriquetral instability
  • Distal radioulnar joint injury
  • ECU subsheath tear
  • Extensor carpi ulnaris tendinopathy

Treatment Options for Ulnar Carpal Instability

Treatment is specific to the nature of carpal instability. Mild cases can be treated by rest, immobilization and anti-inflammatory medication, while severe cases may arthroscopically assisted reconstructive surgery.

Conservative Treatments

Most injuries of this type benefit from rest, immobilization and rehab. A corticosteroid injection may also prove beneficial in providing immediate pain relief.

Surgical Treatments

Surgical intervention may be required to repair or reconstruct damaged ligaments. This process may be done with direct repair, ligament or tendon grafts. Thermal shrinkage and arthroscopy may be options.

Arthroscopic surgery is a common surgery used to treat carpal instability. This involves a small incision to allow for a lens and lighting system so your specialized hand surgeon may view the joint to further delineate the damage for the repair process.

Prognosis for Ulnar Carpal Instability

In most cases, patients with this condition will undergo a period of immobilization or activity modification. From there, treatment will be continued through hand therapy rehabilitation with and without surgery.

Patients should begin physical therapy to try to restore as much mobility and range of motion as possible in order to limit joint stiffness.

If You Believe You Have UCI, Contact HandSport Surgery Institute

Please contact us to schedule an appointment with our talented team. People experiencing ulnar carpal instability should be evaluated to try and prevent further injury and mobility issues.

If you have been injured, it’s important to be evaluated by a highly skilled professional. Call Drs. Mark and Jason Pruzansky at 212-249-8700 to schedule an appointment, obtain an accurate diagnosis, and start to restore comfort to your hand.

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