Ulnar Carpal Impaction
What Is Ulnar Carpal Impaction?
The wrist is a complex joint made up of eight small carpal bones that connect to the five metacarpal bones of the hand. These bones form multiple small joints, allowing intricate wrist movements.
The radius forms the main joint with the wrist bones. The ulna is separated from the wrist bones by a cartilage-and-ligament structure called the TFCC, which helps stabilize and cushion the ulnar side of the wrist.
Ulnar carpal impaction, also called ulnar impaction syndrome, occurs when the ulnar head repeatedly presses against the carpal bones and the triangular fibrocartilage complex (TFCC).
Over time, this pressure can wear down cartilage and joint surfaces, leading to pain and degeneration. This condition is commonly seen in individuals with positive ulnar variance, where the ulna is slightly longer than the radius, increasing stress on the ulnar side of the wrist.
Symptoms of Ulnar Carpal Impaction
Patients often notice pain on the ulnar side of the wrist (the pinky-finger side) which may be constant or occur only during activity. Swelling and tenderness over the TFCC are common. Some patients experience a clicking or popping sensation when moving the wrist.
Pain is usually worse with gripping, lifting, or twisting motions, and rotation of the forearm (pronation or supination) may feel restricted. In more advanced cases, patients may feel instability or difficulty performing daily tasks.
Causes of Ulnar Carpal Impaction
The most common cause is positive ulnar variance, where the ulna extends further than the radius. Previous fractures of the distal radius, degenerative changes in the TFCC, or repeated loading of the ulnar side during sports, work, or manual labor can also contribute.
Rarely, prior surgeries such as radial head resection or premature growth plate closure may alter wrist mechanics and increase risk. Over time, these factors can lead to degeneration of the TFCC and ulnar carpal bones.
Diagnosis of Ulnar Carpal Impaction
Doctors diagnose ulnar carpal impaction through a physical exam and imaging studies. Tests like the ulnar impaction test help identify pain during wrist movement. X-rays can measure ulnar variance and detect bone alignment or degenerative changes.
MRI provides detailed images of the TFCC, cartilage, and ligaments. In some cases, diagnostic injections are used to confirm the source of pain and may provide temporary relief.
Treatment Options
Non-surgical treatment often relieves symptoms. Patients may rest the wrist, avoid aggravating activities, apply ice, take anti-inflammatory medication, and use wrist braces or orthoses. Physical therapy strengthens forearm and wrist muscles, especially the extensor carpi ulnaris, to reduce stress on the ulnar side.
Surgery is considered when symptoms persist. Options include the wafer procedure, where a small portion of the distal ulnar head is removed; ulnar shortening osteotomy, which shortens the distal ulna to reduce pressure; if there is significant arthritis/instability at the distal radioulnar joint (DRUJ), salvage procedures such as Darrach (often older/low-demand) or Sauvé–Kapandji (selected cases) may be considered.
The choice depends on age, activity level, and severity of degeneration.
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Prevention and When to Seek Care
You can’t always prevent it (especially if anatomy contributes), but you can reduce flare-ups with conditioning, technique changes, pacing, and avoiding painful overload.
Persistent ulnar-sided wrist pain, clicking, or instability should prompt evaluation by a hand and wrist specialist. Early diagnosis and treatment can prevent further damage, relieve pain, and restore wrist function.
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