한정형외과학회지：제 42 권 제 5 호 2007

J KoreanOrthop Assoc 2007; 42: 688-691

688

통신저자：권 오 수대전광역시 중구 대흥동 520-2대전성모병원 정형외과TEL: 042-220-9867,9530ㆍFAX: 042-221-0429E-mail: oskn@catholic.ac.kr

Address reprint requests toOh Soo Kwon, M.D.Daejeon St. Mary's Hospital, 520-2, Daeheung-dong, Jung-gu, Daejeon 301-732, KoreaTel: +82.42-220-9867, 9530, Fax: +82.42-221-0429E-mail: oskn@catholic.ac.kr

Fig. 1. Plain radiograph of the left wrist shows a dislocation of the pisiform with displacement.

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

가톨릭 학교 의과 학 성모병원 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.

Although the precise mechanism of injury was

Acute Isolated Pisiform Dislocation 689

Fig. 5. Radiographs taken 24 months after surgery shows a wellreduced position of the pisiform.

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

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

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

unclear, he recalled suffering a direct blow to the

volar aspect of the wrist.

A physical examination revealed tenderness over

the hypothenar eminence. The wrist motion was

restricted by pain and swelling. He did not have

any history of ligament laxity. The neurovascular

examination of ulnar artery and nerve was normal.

The radiographs of the left wrist showed an

isolated dislocation of the pisiform towards the

ulnar with a separation of the pisotriquetral joint

in the palmar-dorsal supine position as well as a

shift toward the dorsal in the lateral view. 3D CT

(computed tomography) showed no other injuries to

the bone and wrist but a displaced pisiform.

An arthroscopic examination of the wrist joint

was performed under general anesthesia but did

not show any other intraarticular lesions. A closed

reduction of the pisiform was attempted under a

C-arm image intensifier. Direct pressure was

applied to relocate the bone with a slightly dorsi-

flexed position. However, stable reduction was not

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

one Kirschner wire percutaneously. The wrist was

immobilized with a long arm plaster splint in 25o

of dorsiflexion for 3 weeks. The splint and kirsch-

ner wire were removed 3 weeks later, at which time

physiotherapy and active exercise were initiated.

Eight weeks after surgery, the radiographs revea-

led the pisiform to have relocated to the correct

position. At the 24 months follow-up, the patient

was clinically well without any pain or limitation

of motion, and full recovery of his grip strength.

DISCUSSION The pisiform bone lies in the proximal row of the

carpal bones and articulates dorsally with the

triquetrum. Because the pisiform has a flat arti-

cular surface, it relies mainly on its many soft

tissue attachments for stability6), such as FCU

(Flexor carpi ulnaris) tendon, ulnar pisotriquetral

ligament, pisometacarapal and pisohamate liga-

ment being primary stabilizers of pisotriquetral

joint3,6). The pisotriquetral joint is tightly constr-

ained by both the transverse carpal ligament and

ulnar collateral ligament. Because of the insertion

of all these structures, the pisiform is an important

stabilizing structure of the wrist and also acts as

a lever to provide extra stability when the wrist is

flexed6). Immerman2) suggested two possible me-

chanisms that may cause a dislocation of the

pisiform: direct external force or traction by the

FCU tendon. It appears that the latter mechanism

occurs more often e.g. a fall on the hand with the

wrist in the dorsiflexed position at the moment of

impact or increase tension on the ligaments

attached to the pisiform while lifting heavy

objects1). The normal force of this tendon tends to

pull the pisiform proximally and medially, and

diagnostic radiography confirms that the bone to

be dislocated in this direction. In our case, the

dislocation appeared to be secondary to acute

dorsiflexion of the wrist joint with strong traction

by the FCU tendon. The pisotriquetral joint appe-

ared to be wide on the radiographs and CT.

Treatment includes immobilization after a closed

reduction, an open reduction with internal fixation

and a resection of the pisiform4,5,9). Nonsurgical

treatment has been initially attempted in acute

cases3,8,10). Sharara et al10) recommended a closed

reduction and immobilization. Kubiak3) suggested

that simple immobilization is justified in cases with

isolated dislocation. There were some differences

regarding the position of the wrist in immobiliz-

ation1,4,7,10). Ishizuki et al1) noted that a dislocation

and reduction of the pisiform is dependent on the

wrist position. Minami et al5) reported a redisloc-

ation 3 months after immobilization in 20o palmar

flexion of the wrist and the neutral position of

forearm. Sharara et al10) suggested the forearm to

be in a full pronation position to maintain the FCU

in the relaxed state. This allows the pisiform to

stabilize in a normal orientation and prevent

redislocation. It is believed that in this case, stable

relocation was obtained in the slight extension

position of the wrist in addition to percutaneous

fixation to the triquetrum.

An open reduction and internal fixation of the

pisiform might be employed in combined carpal

injurues5,9). Most authors favor an excision of the

dislocated pisiform bone either initially or second-

arily in cases of persistent pain or recurrent

dislocation because of rapid rehabilitation and

recovery to normal function1,2,5). Ishizuki et al1)

performed a resection of the pisiform 5 months

after the initial conservative treatment. Minami et

al5) inevitably resected the pisiform in the case of

a redislocation followed by an open reduction and

internal fixation. Some authors suggested a pri-

mary excision of the pisiform in acute disloc-

ation4,7). Therefore, a surgical resection is recom-

mended if recurrent dislocations occur or the

Acute Isolated Pisiform Dislocation 691

disability remains after conservative treatment. An

isolated dislocation of the pisiform can be neglected

in cases associated with multiple injuries in the

upper extremities. A high index of suspicion is

required to identify this type of injury in traumatic

patients. It is believed that our technique is an

effective and reliable method for treating a

dislocated pisiform.

REFERENCES 1. Ishizuki M, Nakagawa T, Itoh S, Furuya K: Positional

dislocation of the pisiform. J Hand Surg Am, 16: 533-535,

1991.

2. Immermann EW: Dislocation of the pisiform. J Bone Joint

Surg Am, 30: 489-492, 1948.

3. Kubiak R, Slongo T, Tschäppeler H: Isolated dislocation

of the pisifrom: an unusal injury during a cartwheel maneuver.

J Trauma, 51: 788-789, 2001.

4. McCarron RF, Coleman W: Dislocation of the pisiform

treated by primary resection. A case report. Clin Orthop Relat

Res, 241: 231-233, 1989.

5. Minami M, Yamazaki J, Ishii S: Isolated dislocation of the

pisiform: a case report and review of the literature. J Hand

Surg Am, 9: 125-127, 1984.

6. Moojen TM, Snel JG, Ritt MJ, Venema HW, den Heeten

GJ, Bos KE: Pisiform kinematics in vivo. J Hand Surg Am,

26: 901-907, 2001.

7. Muñiz AE: Unusual wrist pain: pisiform dislocation and

fracture. Am J Emerg Med, 17: 78-79, 1999.

8. Sundaram M, Shively R, Patel B, Tayob A: Isolated

dislocation of the pisiform. Br J Radiol, 53: 911-912, 1980.

9. Schädel-Höpfner M, Böhringer G, Junge A: Dislocation

of the pisiform bone after severe crush injury to the hand.

Scand J Plast Reconstr Surg Hand Surg, 37: 252-255, 2003.

10. Sharara KH, Farrar M: Isolated dislocation of the pisiform

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