Displaced Flap Tears of the Triangular Fibrocartilage Complex: Frequency, Flap Location, and the "Comma" Sign on Wrist MRI.

The purposes of this study were to estimate the frequency of displaced triangular fibrocartilage complex (TFCC) tears and to describe their MRI characteristics. The total of 3411 wrist MRI examinations assessed showed 20 displaced TFCC tears in 17 patients (frequency, 0.5%). These flaps were characteristically connected to the TFCC via a pedicle ("comma" sign) in 19 of 20 cases and displaced into the distal radioulnar joint also in 19 of 20 cases. Management implications were considered.