Ulnar Grinding Test| Triangular Fibrocartilage Complex (TFCC)

The triangular fibrocartilage complex, abbreviated as TFCC consists of the articular disc, the meniscus homologue, the dorsal and palmar radioulnar ligaments, the ulnolunate and ulnotriquetral ligaments and the extensor carpi ulnaris tendon sheath.

As a center of forearm rotation, the TFCC plays a key role in stabilization, rotation, translation, loading transmission to the wrist and acts as an essential pivot point. Due to its anatomical location as well as its involvement in the key functions of rotation and load bearing, it is highly prone to injuries and attritional wear.

Schmauss et al. (2016) have examined the ulnar grinding test regarding its clinical accuracy. The authors found a sensitivity of 90% and a specificity of 20%. Results varied slightly depending on the Palmer classification. The Palmar classification divides TFCC lesions into traumatic and degenerative origin and into location and kind of lesion.

Due to the poor specificity of this test, the diagnostic value of this test is rather weak. Interestingly, MRI imaging did not perform better and reached a comparably high level of sensitivity and poor specificity in this study.

The ulna grinding test is conducted with the patient’s forearm fixed and the wrist held in dorsiflexion. Then, an axial load is applied, while the wrist is rotated and deviated in ulnar direction.

This test is positive in the case that pain and crepitations are reproduced.

21 OF THE MOST USEFUL ORTHOPAEDIC TESTS IN CLINICAL PRACTICE

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Other orthopedic tests for the triangular fibrocartilage complex are:

• TFCC Compression Test
• Fovea Sign

Other common tests for injuries at the wrist are:

• Watson / Scaphoid Shift Test for Scapholunate Instability
• Distal Radioulnar Joint / DRUJ Test
• Lunotriquetal Ballottement / Shuck Test 

Schmauss, D., Pöhlmann, S., Lohmeyer, J. A., Germann, G., Bickert, B., & Megerle, K. (2016). Clinical tests and magnetic resonance imaging have limited diagnostic value for triangular fibrocartilaginous complex lesions. Archives of orthopaedic and trauma surgery, 136(6), 873-880.

Rekant, M. (2019). Injuries to the Triangular Fibrocartilage Complex. In Sports Injuries of the Hand and Wrist (pp. 235-253). Springer, Cham.