Definition
- Abnormal translation of the distal ulna relative to the sigmoid notch of the radius
- Classified by direction as dorsal or volar, by timing as acute or chronic
Anatomy
- Sigmoid notch is shallow, so stability depends mainly on soft tissues
- Dorsal and palmar radioulnar ligaments have superficial and deep limbs
- Deep limbs (ligamentum subcruentum) insert into the ulnar fovea
- TFCC, ECU subsheath, pronator quadratus and interosseous membrane are secondary stabilisers
Aetiology
- Fall on outstretched hand with forced rotation
- Distal radius fractures with ulnar styloid base fracture
- Galeazzi and Essex-Lopresti injuries
- Malunion of the distal radius
Classification
Palmer (TFCC tears)
| Class | Description |
|---|---|
| 1 | Traumatic |
| 2 | Degenerative |
Original publication Palmer AK. Triangular fibrocartilage complex lesions: a classification. J Hand Surg Am. 1989;14(4):594-606.
Clinical Features
- Ulnar sided wrist pain and clicking with rotation
- Prominent ulnar head in dorsal instability
- Piano key sign
- Ballottement test compared with the other side
- Ulnar fovea sign suggests foveal TFCC disruption
Investigations
- True lateral radiograph of the wrist
- Bilateral CT in pronation, neutral and supination
- MRI or MR arthrogram for TFCC tears
- Arthroscopy with the hook test for foveal detachment
Management
Acute
- Reduce and immobilise in the stable position in an above elbow cast
- Fix large ulnar styloid base fractures
- Repair foveal TFCC detachment open or arthroscopically
- Correct associated radius fractures or malunion first
Chronic
- Adams and Berger anatomic radioulnar ligament reconstruction with palmaris longus graft
- Corrective osteotomy for malunion
- Sauvé-Kapandji or ulnar head replacement for associated arthritis
Complications
- Recurrent instability
- Loss of forearm rotation
- DRUJ arthritis
- Dorsal sensory branch of ulnar nerve injury
Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.