A 46-year-old male was referred to our clinic for persistent ulnar-sided wrist pain 9 weeks after sustaining a traumatic injury while playing volleyball. The patient unsuccessfully underwent nonoperative management for a suspected injury to the triangular fibrocartilage complex. After magnetic resonance imaging revealed a lesion of the distal ulna, he was treated with diagnostic wrist arthroscopy and Bowers hemiresection. The diagnosis of osteonecrosis was confirmed through histology. While traumatic osteonecrosis of the carpal bones has been described, no previous literature was found on traumatic osteonecrosis of the distal ulna. Treatment with diagnostic wrist arthroscopy and Bowers hemiresection resulted in an excellent outcome at 12 months after surgery.