Triangular Fibrocartilage Complex (TFCC) Degeneration/Tears
A TFCC injury typical presents with ulnar sided wrist pain and can result in a distal radioulnar joint (DRUJ) injury. 1 The triangular fibrocartilage complex (TFCC) is a fibrocartilaginous structure located on the ulnar side of the wrist. It has 4 attachments to the ulnar: 2 inserting at the styloid and 2 inserting at the fovea. 1
The TFCC is comprised of (see Figures 1 and 2): 2
(DRUJ – Distal Radial Ulnar Joint, DL – Dorsal ligament, ECU – Extensor Carpi Ulnaris tendon, LT – Lister’s Tubercle, Lu – Lunate, LR – Lunate Recess/Articular fossa, PL – Palmar ligament Ra – Radius, Sc-scaphoid, SR – Scaphoid Recess/Articular fossa, Sy – styloid, # triangular fibrocartilage complex disc, Tq- Triquetrum, Ul – Ulna, * – Ulnarlunate ligament, @ – Ulnartriquetral ligament)
TFCC injuries are classified by the mechanism of injury and include: Palmer Class 1 (an acute tear) and Palmer Class 2 (chronic degenerative changes). 3
The TFCC is stressed during axial loading, ulnar deviation, and extremes of forearm rotation or wrist extension. 1, 2A single traumatic event and/or a repetitive strain with the aforementioned mechanism can lead to degeneration. This can occur with a fall on an outsretched hand, repetitive loads, such as in pushups or from riding a bike with wrist in extension.
Ulnocarpal impaction syndrome
Lunotriquetral ligament tears
Distal radioulnar joint (DRUJ) subluxation
Guyon’s canal/Ulnar canal syndrome
Hook of hamate fracture
ECU subluxation/snapping tendon
Ulnar Styloid Fracture
Inspection: Prominent ulnar dorsal deviation may indicate a DRUJ injury. 1
Palpation: Fovea sign: pain on palpation between the ulnar styloid, flexor carpiulnaris (FCU), volar aspect of the ulnar head, and pisiform. A positive fovea sign has a sensitivity of 95.2% and a specificity of 86.5%.10 for a TFCC injury. 4
Range of Motion: May be normal or limited to ulnar deviation, supination, and/or pronation.
XRay: DRUJ visualized with widening on the AP, and dorsal or volar displacement on the lateral. Look for ulnar variance, a positive ulnar variance can lead to ulnar impaction syndrome and TFCC tears and degeneration.
US: Can be used with limited effect to visualize hyperaemia, or occasionally tears. Dependent on operator performing the scan.6
CT: Can help confirm DRUJ injury.
MRI plus/minus arthrography: Most accurate in diagnosing TFCC injuries.
Management:1, 2, 7
Surgical management is indicated for TFCC tears with associated fractures or instability.
Class 1A tears (most common): perforation of central TFCC disc with no instability
Dr. David Lawrence (PR ND June 16, 2014)