Case of the Week – Triangular Fibrocartilage Complex Tears

Dr Tom Entwisle

 Anatomy

The triangular fibrocartilage complex (TFCC) is located in the ulnocarpal articulation. Functions include stabilising the distal radioulnar and ulnocarpal joints; shock absorption (it bears approximately 20% of the axial load at the wrist); and increasing range of motion by extending the articular surface of the radius.  It is composed of the triangular fibrocartilage articular disc (TFC), volar and dorsal radioulnar ligaments, the meniscus homologue (MH), volar ulnolunate and ulnotriquetral (vUT) ligaments, the ulnar collateral ligament (UCL) and the extensor carpi ulnaris tendon sheath.

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Pathology

Palmer (1) devised a classification system for TFCC tears based on the mechanism, location and the involved structures, and this has been used to guide treatment. cotwClass I lesions are traumatic injuries and subclassified according to the site of injury. Class II lesions are degenerative injuries and are sub-classified based on the degree of involvement of the adjacent structures.

Clinical

The TFCC has a rich blood supply peripherally which allows tears in these regions to heal and be repaired. The central articular disc is essentially avascular and thus has a limited ability to heal and thus debridement is the mainstay of treatment.

Cases

Select coronal PD fatsat images of the ulnar side of the wrist demonstrating a variety of tears of the TFCC.

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Left – small vertical (top) and oblique (bottom) radial sided tears (Palmer ID).

Centre left – small (top) and large (bottom) central TFC disc tears (Palmer IA).

Centre right – horizontal tears of the TFC disc (Palmer IA).

Right – foveal (top) and ulnar styloid (bottom) tears (Palmer IB).

References

  1. Palmer AK. Triangular fibrocartilage complex lesions: a classification. The Journal of hand surgery. 1989;14(4):594-606.