대한정형외과학회지：제 42 권제5 호 2007 J Korean Orthop Assoc 2007; 42: 688-691

Acute Isolated Pisiform Dislocation - A Case Report -

Oh Soo Kwon, M.D., Seong Pil Choi, M.D., and Ho Yeon Won, M.D. Department of Orthopaedic Surgery, Daejeon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea

급성 단독 두상골 탈구 -증례 보고- 권오수ㆍ최성필ㆍ원호연 가톨릭대학교 의과대학 대전성모병원 정형외과

There are few reports of an isolated dislocation of the pisiform. An isolated dislocation of the pisiform without other injuries involving the carpal bones is particularly uncommon. This type of injury can be neglected in the acute period. We report a case of an isolated dislocation of the pisiform without a carpal bone injury in a young man treated primarily with a closed reduction, pinning and immobilization. Key Words: Pisiform, Dislocation

Isolated dislocation of pisiform is rarely reported in the literature. Isolated dislocation of pisiform without other injuries involving carpal bones are especially uncommon. This type of injury could be neglected in acute period. We report a case of an isolated dislocation of the pisiform without carpal bone injuries.

CASE REPORT A 20-year-old man suffered an injury to his left hand after falling down stairs. The radiographs revealed an isolated dislocation of the pisiform and associated injuries including an ipsilateral distal clavicle fracture and a contralateral intraarticular fracture of the metacarpal base of the thumb. Fig. 1. Plain radiograph of the left wrist shows a dislocation of Although the precise mechanism of injury was the pisiform with displacement.

통신저자 ：권 오 수 Address reprint requests to 대전광역시 중구 대흥동 520-2 Oh Soo Kwon, M.D. 대전성모병원 정형외과 Daejeon St. Mary's Hospital, 520-2, Daeheung-dong, Jung-gu, Daejeon TEL: 042-220-9867,9530ㆍFAX: 042-221-0429 301-732, Korea E-mail: [email protected] Tel: +82.42-220-9867, 9530, Fax: +82.42-221-0429 E-mail: [email protected]

688 Acute Isolated Pisiform Dislocation 689

Fig. 2. Three dimensional reconstructed computed tomography shows the displacement of the pisiform viewing from the radius.

Fig. 4. Radiographs of the left wrist at the immediate postoper- ative period shows a well reduced pisifom fixed with Kirschner wire into the triquetrum.

Fig. 3. Axial view of computed tomography reveals widening of the pisotriquetral joint.

Fig. 5. Radiographs taken 24 months after surgery shows a well unclear, he recalled suffering a direct blow to the reduced position of the pisiform. volar aspect of the wrist. A physical examination revealed tenderness over (computed tomography) showed no other injuries to the hypothenar eminence. The wrist motion was the bone and wrist but a displaced pisiform. restricted by pain and swelling. He did not have An arthroscopic examination of the wrist joint any history of ligament laxity. The neurovascular was performed under general anesthesia but did examination of ulnar artery and nerve was normal. not show any other intraarticular lesions. A closed The radiographs of the left wrist showed an reduction of the pisiform was attempted under a isolated dislocation of the pisiform towards the C-arm image intensifier. Direct pressure was ulnar with a separation of the pisotriquetral joint applied to relocate the bone with a slightly dorsi- in the palmar-dorsal supine position as well as a flexed position. However, stable reduction was not shift toward the dorsal in the lateral view. 3D CT maintained. Therefore, the pisiform was reduced 690 Oh Soo Kwon, Seong Pil Choi, Ho Yeon Won into its position and fixed to the triquetrum using dorsiflexion of the wrist joint with strong traction one Kirschner wire percutaneously. The wrist was by the FCU tendon. The pisotriquetral joint appe- immobilized with a long arm plaster splint in 25o ared to be wide on the radiographs and CT. of dorsiflexion for 3 weeks. The splint and kirsch- Treatment includes immobilization after a closed ner wire were removed 3 weeks later, at which time reduction, an open reduction with internal fixation physiotherapy and active exercise were initiated. and a resection of the pisiform4,5,9). Nonsurgical Eight weeks after surgery, the radiographs revea- treatment has been initially attempted in acute led the pisiform to have relocated to the correct cases3,8,10). Sharara et al10) recommended a closed position. At the 24 months follow-up, the patient reduction and immobilization. Kubiak3) suggested was clinically well without any pain or limitation that simple immobilization is justified in cases with of motion, and full recovery of his grip strength. isolated dislocation. There were some differences regarding the position of the wrist in immobiliz- DISCUSSION ation1,4,7,10). Ishizuki et al1) noted that a dislocation The pisiform bone lies in the proximal row of the and reduction of the pisiform is dependent on the carpal bones and articulates dorsally with the wrist position. Minami et al5) reported a redisloc- triquetrum. Because the pisiform has a flat arti- ation 3 months after immobilization in 20o palmar cular surface, it relies mainly on its many soft flexion of the wrist and the neutral position of tissue attachments for stability6), such as FCU forearm. Sharara et al10) suggested the forearm to (Flexor carpi ulnaris) tendon, ulnar pisotriquetral be in a full pronation position to maintain the FCU ligament, pisometacarapal and pisohamate liga- in the relaxed state. This allows the pisiform to ment being primary stabilizers of pisotriquetral stabilize in a normal orientation and prevent joint3,6). The pisotriquetral joint is tightly constr- redislocation. It is believed that in this case, stable ained by both the transverse carpal ligament and relocation was obtained in the slight extension ulnar collateral ligament. Because of the insertion position of the wrist in addition to percutaneous of all these structures, the pisiform is an important fixation to the triquetrum. stabilizing structure of the wrist and also acts as An open reduction and internal fixation of the a lever to provide extra stability when the wrist is pisiform might be employed in combined carpal flexed6). Immerman2) suggested two possible me- injurues5,9). Most authors favor an excision of the chanisms that may cause a dislocation of the dislocated pisiform bone either initially or second- pisiform: direct external force or traction by the arily in cases of persistent pain or recurrent FCU tendon. It appears that the latter mechanism dislocation because of rapid rehabilitation and occurs more often e.g. a fall on the hand with the recovery to normal function1,2,5). Ishizuki et al1) wrist in the dorsiflexed position at the moment of performed a resection of the pisiform 5 months impact or increase tension on the ligaments after the initial conservative treatment. Minami et attached to the pisiform while lifting heavy al5) inevitably resected the pisiform in the case of objects1). The normal force of this tendon tends to a redislocation followed by an open reduction and pull the pisiform proximally and medially, and internal fixation. Some authors suggested a pri- diagnostic radiography confirms that the bone to mary excision of the pisiform in acute disloc- be dislocated in this direction. In our case, the ation4,7). Therefore, a surgical resection is recom- dislocation appeared to be secondary to acute mended if recurrent dislocations occur or the Acute Isolated Pisiform Dislocation 691 disability remains after conservative treatment. An 4. McCarron RF, Coleman W: Dislocation of the pisiform isolated dislocation of the pisiform can be neglected treated by primary resection. A case report. Clin Orthop Relat in cases associated with multiple injuries in the Res, 241: 231-233, 1989. upper extremities. A high index of suspicion is 5. Minami M, Yamazaki J, Ishii S: Isolated dislocation of the required to identify this type of injury in traumatic pisiform: a case report and review of the literature. J Hand patients. It is believed that our technique is an Surg Am, 9: 125-127, 1984. effective and reliable method for treating a 6. Moojen TM, Snel JG, Ritt MJ, Venema HW, den Heeten dislocated pisiform. GJ, Bos KE: Pisiform kinematics in vivo. J Hand Surg Am, 26: 901-907, 2001. REFERENCES 7. Muñiz AE: Unusual wrist pain: pisiform dislocation and 1. Ishizuki M, Nakagawa T, Itoh S, Furuya K: Positional fracture. Am J Emerg Med, 17: 78-79, 1999. dislocation of the pisiform. J Hand Surg Am, 16: 533-535, 8. Sundaram M, Shively R, Patel B, Tayob A: Isolated 1991. dislocation of the pisiform. Br J Radiol, 53: 911-912, 1980. 2. Immermann EW: Dislocation of the pisiform. J Bone Joint 9. Schädel-Höpfner M, Böhringer G, Junge A: Dislocation Surg Am, 30: 489-492, 1948. of the pisiform bone after severe crush injury to the hand. 3. Kubiak R, Slongo T, Tschäppeler H: Isolated dislocation Scand J Plast Reconstr Surg Hand Surg, 37: 252-255, 2003. of the pisifrom: an unusal injury during a cartwheel maneuver. 10. Sharara KH, Farrar M: Isolated dislocation of the pisiform J Trauma, 51: 788-789, 2001. bone. J Hand Surg Br, 18: 195-196, 1993.

= 국문초록 =

단독 두상골 탈구는 매우 드문 병변으로서 문헌보고를 찾기 쉽지 않다. 대부분의 경우 동측 수근골 및 관절 또는 전완부와 완관절에 심한 손상을 동반하므로 처음 손상의 발생시에 간과되기 쉽다. 따라서 진단과 치료에 관심과 주의를 기울여야 할 것으로 생각된다. 상지 다발성 손상과 동반된 두상골 탈구에서 도수 정복과 경피적 고정술을 시행한 1예를 보고하고자 한다. 핵심 단어: 두상골, 탈구