TFCC tears and Ulnocarpal Impaction
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Posted by firstname.lastname@example.org, 6/26/04 at 4:03:02 PM.
TRIANGULAR FIBROCARTILAGE COMPLEX (TFCC) and ULNARCARPAL IMPACTION (or IMPINGEMENT) SYNDROME
first described in 1981 by Werner and Palmer as the ligamentous and
cartilaginous structures that suspend the distal radius and ulnar
carpus from the distal ulna. It is the the major ligamentous stabilizer
of the distal radioulnar joint (DRUJ) and the ulnar carpals.
Provides for a continuous gliding surface for
flexion-extension and translational movements of the forearm and for
stable rotational movements of the radiocarpal unit about the ulnar
Suspends the ulnar carpus from the dorsal ulnar face of the radius and
cushions the forces directed through the ulnocarpal axis.
MECHANISMS OF INJURY TO TFCC:
- falls onto pronated hyperextended wrist
- twisting w/ palmar rotation
- forced ulnar deviance, such as batting a baseball, subjects the TFC to heavy loads
- associated with distal radius fractures
- ulnocarpal impaction syndrome (see below)
SYMPTOMS: TFCC injuries cause ulnar-sided wrist
pain, frequently with clicking or crepitus and tenderness between the
ulna and triquetrum.
ULNOCARPAL IMPACTION SYNDROME
is impingement of distal ulna on carpi which may arise from positive
ulnar variance or non union of distal ulnar fracture. It is a common
inciting cause of degenerative tears. (Note: those with positive
ulnar variance can develp TFCC tears, and those with TFCC tears often
demonstrate positive ulnar variance.) Patients with a torn TFCC display
positive ulnar variance (radial shortening) on average 4.6 mm versus
2.5 mm for no tear and dorsal angulation of 24° versus 12° for no tear.
increased ulnar variance leads to loading of the ulnocarpal joint
and resultant lunotriquetral disruption, lunate chondral lesion, and
triangular fibrocartilage complex tears
during marked ulnar deviation, compressive load on TFCC, particularly
w/ positive ulnar variance, may increase
may show flattening, subchondral sclerosis or cysts, and/or lytic
changes in lunate and/or triquetrum with similar changes seen
over the distal ulna
- patients may have positive ulnar variance
- in subtle cases, a pronation grip radiograph may demonstrate ulnar variance
positive ulnar variance and lunotriquetral impaction on this
patient. There are subchondral cysts in the ulnar styloid,
indicating degenerative changes from chronic impaction. Subsequent
contrast injection into the DRUJ has extravasated into the radialcarpal
joint, indicating TFCC tear.
Note in this
patient that the contrast injected into the midcarpal joint has
extravasated into the radialcarpal joint and DRUJ, indicating tear of
patient with ulnar impaction syndrome. Note the degenerative changes
(osteophytes and subchondral cysts) in the distal ulna, scaphoid and
lunate (white arrows), along with positive ulnar variance.