Table 1.

Summary table of pisiform dislocation.

Etiology	Direct trauma to the bone, secondary to forced hyperextension of the wrist with contraction of flexor carpi ulnaris tendon.
Incidence	Isolated dislocation of pisiform bone is rare. Only a few case reports have been reported in literature. Incidence of pisiform dislocation when associated with other fractures and carpal dislocations is variable.
Gender ratio	Not known. Most of the case reports have been described in males.
Age predilection	Common in young active adults.
Risk factors	Trauma, forced wrist hyperextension.
Treatment	No clear consensus. Various options include closed reduction and immobilization, open reduction with internal fixation, and resection of the pisiform bone. Ligamentoplasty may be performed when there are tears of pisohamate or pisometacarpal ligaments and to stabilize the FCU tendon.
Prognosis	Early treatment has a better prognosis. Missed pisiform dislocations lead to persistent pain, recurrent dislocation, and development of osteoarthritis of the piso-triquetral or piso-hamate joints. Risk of recurrent instability in delayed presentations.
Findings on imaging	Radiographs of wrist - pisiform is seen projected distinctly separate from the triquetrum. CT– can demonstrate pisiform dislocation and other associated fractures/dislocations if present. MRI– demonstrates associated ligamentous or tendon injuries, such as flexor carpi ulnaris tendon tear. MRI can look for associated ulnar or median nerve injuries.