TFCC Assessment

Look for and report:

• Defects in the TFC itself
• Tears of the two main ulnar attachments
• Tears of the volar and dorsal ulnotriquetral ligaments
• Lunotriquetral ligament tear

The TFCC is attached on the radial side to the most distal ulnar part of the radius. The attachment is not to bone but to a thin layer of articular cartilage. The signal change that occurs at this attachment should not be misinterpreted as a tear.

On the ulnar side, the attachment of the TFC is more complex. The principal attachment is to the base of the ulnar styloid through a loose ligamentous attachment interspaced with fibre adipose tissue.

There are ulnolunate and ulnotriquetral ligaments on the volar aspect of the TFC. These lie deep to the ulnar nerve.

Perforations of the TFC occur with increasing age, particularly are common over the age of 40. Clinical correlation thus important. In symptomatic patients, arthographic studies have demonstrated similar findings in the contralateral asymptomatic wrist.

Imaging

Tears of the TFC may be partial or complete. If partial may involve the proximal (most commonly) or distal articular surfaces. May be on the radial or ulnar sides.

Much needs to be clarified about the clinical significance of these injuries. Currently thought that ulnar sided injuries are more important than radial and proximal partial tears are more common, and possibly more clinically significant, than distal partial tears.

Partial tears of the distal surface of the TFC will not be detected by distal radio ulnar joint injection and partial tears of the proximal surface will not be detected by the more commonly performed radio carpal injection. Injection of both compartments may also be required to demonstrate the (rare) unidirectional tear.