Triangular fibrocartilage complex tears.

Abstract

The main structural component of TFCC is triangular fibrocartilage (TFC) proper which originates from the ulnar border of the sigmoid notch and attaches to the fovea and the styloid process of the ulna. Other main structures of TFCC include dorsal and palmar capsules, meniscus homologue, ulnar collateral ligament (UCL), dorsal and palmar distal radioulnar ligaments (triangular ligament named by Nakamura and his associates2), ulnocarpal ligaments (ulnolunate and ulnotriquetral ligaments) and tendon floor of the extensor carpi ulnaris tendon. TFC proper consists of two layers, superficial and deep layers. Both originate from the sigmoid notch of the radius where a great portion of the deep layer attaches to the fovea of the ulna, and the most superficial layer attaches to the meniscus homologue and ulnar styloid process. Recent functional anatomic and biomechanical studies have revealed that the deep layer of the TFCC mainly contributes to the dynamic stability of the distal radioulnar joint (DRUJ).36 This fact is also used as an explanation of the reason for not having a big influence on the stability of DRUJ, since 40–60% of distal radius fractures associate with tip fracture of the ulnar styloid process.711 Nakamura and his associates have reported functional anatomies of the TFCC by meticulous anatomical and biomechanical studies.24 They have reported that TFCC is presenting a hammock-like structure and ulnar side of the TFCC is merged to meniscus homologue and UCL (Fig. 1). When pulling the ulnar side of the TFCC, the so-called pulling up of the string supporting a hammock, the entire TFCC has tension (Fig. 2). By performing an ulnar shortening osteotomy, the whole TFCC becomes tense, and it is assumed that the stability of the DRUJ is acquired, and this serves as a reason for the usefulness of performing ulnar shortening osteotomy for DRUJ instability. Moreover, as described before, they have named the triangular ligament which combines the dorsal and palmar distal radioulnar ligaments, and inserts to the fovea of the ulna and gives