Ulnar Carpal Impaction

What is Ulnar Carpal Impaction?

The wrist is a complex joint made up of 8 carpal bones aligned in two rows, with four bones present in each row. The carpal bones are further connected to 5 metacarpal bones that form the palm of the hand. Each small bone forms a joint with the bone next to it. Thus, the wrist joint is made up of many small joints. The two bones of the forearm, the radius, and ulna, also form a joint with the first row of carpal bones.

Ulnar carpal impaction, also referred to as ulnar impaction syndrome or ulnar abutment or ulnocarpal loading, is a common cause of ulnar sided wrist pain. It is a degenerative condition in which the ulnar head impacts the ulnar-sided carpus and the triangular fibrocartilage complex (TFCC).

Symptoms of Ulnar Carpal Impaction

Symptoms include:

• Chronic or subacute ulnar-sided wrist pain 
• Swelling of the wrist
• Limitation of wrist movement
• Limitation of forearm movement

Causes of Ulnar Carpal Impaction

Causes include:

• Previous fracture
• Congenital anatomic variant
• Premature closure of the distal radius growth plate 
• History of radial head resection
• Repeated loading of the ulnar sided-carpus in daily activity

Diagnosis of Ulnar Carpal Impaction

Ulnar carpal impaction is diagnosed with the help of an X-ray and physical examination. An MRI may also be helpful. These tests can assist your doctor in determining the involved or injured structures in the wrist.

Treatment for Ulnar Carpal Impaction

Treatment is aimed at removing the mechanical impaction of the ulna with the triangular fibrocartilage complex and ulnar carpal bones. Nonsurgical options include rest, application of ice and anti-inflammatory medications. 

The surgical options may include the following procedures:

• The wafer procedure can be performed either as an open procedure or arthroscopically. The wafer procedure involves surgical resection of the distal 2-3 mm of the ulnar head.
• Ulnar shortening involves performing an osteotomy in the ulnar shaft and removing a small section of bone to shorten the overall length of the bone. The bone is then stabilized with a plate and screws.
• A Darrach procedure involves complete or partial ulnar head resection which is performed in advanced cases.
• Sauve Kapandji procedure involves arthrodesis of the distal radioulnar joint with distal ulnar pseudoarthrosis.

Prevention of Ulnar Carpal Impaction

You can learn to use certain techniques to avoid wrist problems. Stretching your muscles before starting any exercise or sports activity significantly reduces your risk. Also, remember to stretch the muscles slowly and hold the stretch for some time instead of making many rapid stretches. Warm-up every time before you stretch. Participate in a conditioning program to keep your muscles flexible and strong. Use protective gear that is appropriate for the sports activity you are involved in. Also use of a functional brace to keep the wrist stable may be helpful.