Removing the pisiform bone from the wrist is called a pisiformectomy. A recent study of 21 patients with pisiformectomy reported good results. Everyone got relief from their pain.
All but one person could use the wrist for any activity without pain. The one patient with pain reported problems only with strenuous wrist motion.
Everyone had wrist motion on the pisiformectomy side equal to wrist motion on the unoperated side. Wrist function didn't seem to be hampered by removing the bone.