The radiograph and CT scan demonstrate a comminuted pisiform fracture. Incongruity and/or arthritis at the pisotriquetrial joint can cause ulnar-sided wrist pain. Studies show a pisiformectomy is a reliable way to relieve this pain and doesn’t impair wrist function. Lam et al in a study of 20 patients who underwent pisiformectomy for pisotriquetral joint dysfunction reported 15 with complete relief and 5 with mild discomfort at a mean follow-up of 65 months. They reported "no significant differences in grip strength and wrist movement, static strength and dynamic power" when compared to the unaffected wrist.
Pierre A, Le Nen D, Hu W, Dubrana F, Saraux A, Chaise F. Treatment of piso-triquetral pain by excision of the pisiform: report of fifteen cases. Chir Main. 2003 Feb;22(1):37-42.
PMID:12723308 (Link to Abstract)
Lam KS, Woodbridge S, Burke FD. Wrist function after excision of the pisiform. J Hand Surg Br. 2003 Feb;28(1):69-72.
PMID:12531672 (Link to Abstract)