Ulnocarpal Abutment Syndrome With Triquetrum Degeneration

We present the case of a 47-year-old patient with a congenital positive ulnar variance and elucidate its effects on nearby structures in relation to ulnocarpal abutment syndrome (UAS). While magnetic resonance imaging (MRI) helped to identify soft tissue changes in the wrist, the use of an arthrogram, in this case, allowed for a more comprehensive and detailed analysis of the ligaments and soft tissues. Image findings included a complex degenerative tear of the disc of the triangular fibrocartilage (TFCC), a degenerated triquetrum, and partial tears of the scapholunate and lunotriquetral ligaments. Mild dorsal angulation of the lunate was noted, representing dorsal intercalated segmental instability (DISI), suggesting scapholunate ligament injury. Palmar classification was utilized to classify the extent of the TFCC injury as Type IIE. This case shines a light on the presentation of UAS in a patient that was not the usual demographic affected by this pathology, as well as their UAS affecting the triquetrum rather than the more commonly associated lunate.