Ulnar Impaction Syndrome

Ulnar Impaction Syndrome is a degenerative wrist condition caused by the ulnar head impacting upon the ulnar-sided carpus and triangular fibrocartilcage complex resulting in degeneration of these structures.

It is also called ulnar abutment, ulnocarpal loading and impingement syndrome

Causes of Ulnar Impaction Syndrome

The syndrome occurs in people with positive ulnar variance which may occur because of

• Distal radius fractures with radial shortening
• Radial head excision
• Essex Lopresti fracture
• Galeazzi fracture
• Excessive repeated loading of the ulnar-carpus in daily activities
• Madelung deformity

Clinical presentation of Ulnar Impaction Syndrome

Ulnar impaction syndrome mostly affects the  commonly presents in middle-aged patients. Patients present with chronic or sub-acute ulnar-sided wrist pain especially on dorsal side of triangular fibrocartilage.

Pain is exacerbated by activity especially firm grip, pronation and ulnar deviation of the wrist. [These movements cause an increase in ulnar variance.]

Ballottement test

WIth wrist positioned in ulnar deviation, dorsal and palmar displacement of the ulna is attempted. The test is considered positive if pain is produced.

Nakamura’s Ulnar Stress Test

With wrist in ulnar deviation and pronation, the wrist is axially loaded, flexed and extended. The test is considered positive if pain is produced.

Fovea test

This test is done to evaluate for TFCC tear or ulnotriquetral ligament tear. The test is performed by palpation of the ulnar wrist between the styloid and flexor carpii ulnaris tendon.

Imaging in Ulnar Impaction Syndrome

Xrays are normal in early disease. A positive ulnar variance may be noted. Degenerative changes in ulnar side of the carpal bones may be noted when the condition advances.

MRI shows signal changes in ulnar side of proximal part of lunate, radial side of proximal part of triquetrum. the changes noted may be

• Subchondral sclerosis
• Bone edema
• Subchondral cyst
• Chondromalacia of distal ulnar cartilage
• Increase in central TFCC signal
• Lunotriquetral ligament tear

Treatment of Ulnar Impaction Syndrome

Treatment of ulnar impaction syndrome varies depending on the amount of ulnar variance, and the severity of pathological changes, the contour of the distal ulnar and the presence of lunotriquetral instability.

Mild cases may be treated with analgesics and local therapy including heat and analgesic gel

Surgical treatment options include

Open Wafer Procedure

Surgical resection of the distal 2–3 mm of the dome of the ulnar head

Ulnar Shortening

Excision of a 2-3mm slice of the ulnar shaft followed by fixation

Arthroscopic Wafer Procedure

Minimally invasive and allows rapid return to normal activities.

Darrach Procedure

Complete or partial ulnar head resection. Done in advanced lesions

Sauve´ – Kapandji procedure

Arthrodesis of the distal radioulnar joint with distal ulnar pseudoarthrosis

Radial Osteotomy

When ulnocarpal impaction occurs following fractures of radius, the procedure can restore normal joint anatomy