Purpose Tear of the triangular fibrocartilage complex (TFCC) and nonunion of the ulnar styloid are common lesions resulting from upper extremity injuries such as distal radius fractures. Whereas ulnar styloid fractures are a common feature of the distal radius fracture pattern, symptomatic nonunions of the ulnar styloid are found in a minority of these injuries. The purposes of this study were to confirm the association of symptomatic ulnar styloid nonunions and TFCC tears, and to report intra-articular findings and clinical outcomes for the concurrent arthroscopic management of TFCC tears and open excision of ulnar styloid nonunions in a consecutive series of patients. Methods We retrospectively reviewed the medical records of 8 consecutive patients who underwent open excision of an ipsilateral ulnar styloid nonunion fragment and concurrent diagnostic arthroscopy. The diagnosis of TFCC tear was made by magnetic resonance imaging preoperatively in only 5 of 8 patients. We assessed outcomes with the Disabilities of the Arm, Shoulder, and Hand questionnaire and the visual analog scale. Results Arthroscopic findings demonstrated full-thickness chondral injury on the dorsum of the triquetrum with a tear of the dorsal radiolunotriquetral ligament and avulsion of the ulnar margin of the TFCC from the extensor carpi ulnaris subsheath. The clinical outcome scores showed statistically significant improvement (p<.05) from the preoperative baseline, with a mean Disabilities of the Arm, Shoulder, and Hand score of 3.69 (SD, 9.68) and a mean visual analog scale pain score of 1.0 (SD, 0.83) postoperatively. Conclusions Symptomatic ulnar styloid nonunions can be associated with TFCC tears, and diagnostic arthroscopy should be considered in all patients who are candidates for open excision of an ulnar styloid nonunion. Concurrent arthroscopic TFCC repair and open excision of the ulnar styloid fragment is an effective surgical approach for this combined injury pattern.