Imaging description

A triangular fibrocartilage (TFC) tear appears as a linear band of increased signal intensity (Figure 33.1). With complete tears the signal extends to the proximal and distal articular surfaces. MR imaging may demonstrate an asymptomatic defect of the TFC (Figure 33.2).

Importance

With increasing age, defects and central communication within the TFC increase in frequency. Non-communicating TFC defects are worthwhile to record specifically because they can be associated more reliably with symptomatic wrists than communicating TFC defects. Non-communicating and communicating defects of the TFC near the ulnar attachment have a more reliable association with symptomatic wrists than do radial communicating defects.

Typical clinical scenario

Patients with a TFC tear present with ulnar-sided pain. The radial-sided communicating TFC defects are commonly seen bilaterally and in asymptomatic wrists.

Differential diagnosis

Differential diagnosis includes TFC tear, asymptomatic defects, and pseudotear.

Teaching point

There are no specific differentiating features on MR imaging separating a traumatically induced tear of the TFC from one caused by degeneration. The appearance of these lesions may also be similar in symptomatic and asymptomatic individuals; therefore, determining the clinical relevance of these lesions and their correlation with patients’ symptoms may be difficult.