[Fractures of the Triquetrum - a Frequent Cause of Post-Traumatic Ulnar-Sided Wrist Pain]

Fractures of the triquetrum are the second most common carpal fractures after scaphoid fractures and represent a frequent cause of post-traumatic ulnar-sided wrist pain. Dorsal shear fractures account for approximately 93% of all triquetral fractures and are therefore by far the most common fracture type. Two pathomechanisms have been proposed: avulsion by the dorsal ligamentous attachments to the triquetrum and impaction of the dorsal cortex by a prominent ulnar styloid. The dorsal shear/ avulsion fracture is commonly associate with a localized tenderness to palpation over the dorsal aspect of the triquetrum. The diagnosis is confirmed by a lateral wrist X-ray, and, if necessary, also by CT. Treatment is for purely osseous lesions as well as for osteoligamentous avulsion fractures conservative with immobilization in a short-arm cast for 3 weeks. Residual symptoms may persist for several months and are not uncommon. Fractures of the triquetral body are considerably much less frequent and may occur as part of more complex carpal injuries, such as perilunate fracture-dislocations. In these cases, CT is recommended in addition to standard radiographs to accurately define the fracture pattern. Palmar cortical fractures may represent an avulsion injury of the strong palmar portion of the lunotriquetral (LT) ligament. Consecutively, the diagnostic work-up should include magnetic resonance imaging (MRI) in addition to standard radiographs of the wrist. Wrist arthroscopy is the gold standard to confirm an associated LT ligament rupture, followed consecutively by a transfixation of the LT joint.