A complete dislocation of the thumb metacarpal Multiple dislocations of a single finger are rare. We report a patient with complete dislocation of the thumb metacarpal, a condition not reported previously. A 9 year follow-up shows the patient to have a normal-appearing, strong, and painless hand.

J. Russell Moore, M.D., Charles A. Webb, Jr., M.D., and R. C. Thompson, M.D., Baltimore, Md.

Dislocation of both interphalangeal joints of a finger has been described in several reports. 1-4 In this case a complete dislocation of the thumb metacarpal is presented. Our review of the literature suggests this to be a unique injury. Case history A 31-year-old, right-handed stevedore fell down a flight of stairs while intoxicated and injured his right hand, wrist, and elbow. He was unable to recall the event. From the Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, Md. Received for publication May 18, 1978. Reprint requests: J. Russell Moore, M.D., Department of Orthopaedic Surgery, The Johns Hopkins Hospital, Baltimore, MD 21205.

On examination in the emergency room the right hand and thenar eminence were swollen and tender. The right elbow was dislocated posteriorly. Neurological status and vascular status were normal. Radiographs (Figs. I and 2) showed a dorsal dislocation of the metacarpophalangeal joint of the thumb with volar plate disruption proximal to the sesamoids. There was a dislocation without fracture of the carpometacarpal joint. In the operating room an axillary block was administered and the elbow dislocation was easily reduced. The carpometacarpal joint was easily reduced but was unstable. After an attempt at closed reduction of the metacarpophalangeal joint, the joint was exposed through an oblique volar incision. The metacarpal head apparently had buttonholed through the thenar muscle mass and spontaneously reduced when the muscle bellies and flexor pollicis longus tendon were retracted. The tom radial collateral ligament was repaired and the carpometacarpal joint was stabilized with two Kirschner

Fig. 1. Anteroposterior and oblique radiographs obtained on initial visit. Note the unusual foreshortened appearance of the thumb metacarpal. Also, the sesamoids remained attached to the proximal phalanx, indicating disruption of the proximal volar plate. 0363-5023/78/060547+03$00.30/0

© 1978 American

Society for Surgery of the Hand

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Fig. 3. Intraoperative radiograph demonstrating reduction of the metacarpophalangeal joints and stabilization of the carpometacarpal joint with two Kirschner wires. Fig. 2. A radiograph at right angles shows that two dislocations have occurred in the same digit.

wires, as described by Wagner. 5 The metacarpophalangeal joint was immobilized in slight flexion for 4 weeks, as recommended by Bunnell,6 and the carpometacarpal joint was held in position for 6 weeks (Fig. 3). A 9 year follow-up showed the patient to be asymptomatic with a strong, painless grip and a powerful pinch. Metacarpophalangeal flexion ranged from 0° to 45° in both hands. There was no instability of the carpometacarpal joint. The patient had equal motion in this joint in both hands (Fig. 4). The right elbow lacked 10° of full extension.

Discussion Dislocation of the thumb metacarpophalangeal joint is five times more frequent than that of any other metacarpophalangeal joint. 7 The classic mechanism for dorsal dislocation is forced hyperextension. 8 In this case a radial collateral ligament tear and a volar plate disruption accompanied the dislocation. The interposed

volar plate and flexor pollicis longus tendon prevented closed reduction. Dislocation without fracture of the carpometacarpal joint is uncommon. 9 A longitudinally directed force with the carpometacarpal joint in slight flexion usually is responsible for this dislocation. In this patient it is surmised that the dislocations occurred in a sequential fashion from distal to proximal. The anteroposterior and oblique projections (Fig. I) might suggest a condition other than traumatic dislocation and the need for radiographs from other angles is stressed (Fig. 2). A double dislocation of the thumb metacarpal is presented. There were no symptoms or disability in this patient 9 years following reduction. REFERENCES 1. Ikpeme JO: Dislocations of both interphalangeal joints of one finger injury. Br J Accident Surg 9:71-3, 1977

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Fig. 4. Nine years after injury the patient has symmetrical range of motion and a painless, powerful grip and pinch. 2. Nathan F, Schlein P: Multiple dislocations of a single finger. Hand 5:52-4, 1973 3. Bartels M: Traumatische Luxationen. Arch Klin Chir 16:654, 1874 4. Freitag P, Hirasuna SM, Milgram JW: Double dislocation of the finger: A rare occurrence. Physician Sportsmed Oct 1977, pp 83-4 5. Wagner CJ: In Crenshaw AH, Editor: Campbell's operative orthopaedics, ed 5, St Louis, 1976, The C. V. Mosby Co, pp 193-4

6. Bunnell S: Surgery of the hand, Philadelphia, 1956, J B Lippincott Co, p 609 7. MacLaughlin HL: Complex' 'locked" dislocations of the metacarpophalangeal joints. J Trauma 5:683-8, 1965 8. Eaton RG: Joint injuries of the hand, Springfield, Ill, 1971, Charles C Thomas, Publisher, p 57 9. Eaton RG: Joint injuries of the hand, Springfield, Ill, 1971 Charles C Thomas, Publisher, p 66

A complete dislocation of the thumb metacarpal.

A complete dislocation of the thumb metacarpal Multiple dislocations of a single finger are rare. We report a patient with complete dislocation of the...
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