Hand CASE 6
CASE 6
A 21-year-old male was involved in an altercation. During the course of this altercation, he struck a hard object after missing his opponent. He immediately developed pain over the ulnar side of his hand and was seen in the emergency room. X-rays are shown (Fig. 4–5A and B).
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Figure 4–5 A–B
The most likely diagnosis is:
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Fracture of the fifth metacarpal shaft
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Fracture of the fifth metacarpal neck
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Dislocation of the fifth CMC joint
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None of the above
Discussion
The correct answer is (B). This patient has sustained a fifth metacarpal neck fracture. This fracture is also known as a “boxer’s fracture.” It usually occurs from impact of the ulnar side of the hand against a hard object, leading to a sudden flexion force on the fifth metacarpal neck and distal shaft that results in a fracture of the fifth metacarpal in the very distal shaft or in the neck, with dorsal angulation of the apex. Most commonly, the patient does not have malrotation but tends to have an angulatory deformity.
A decision is made to treat the patient. Which of the following factors affect the treatment of this patient?
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Measurement of the angulation at the fracture site
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Presence of an open wound
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Presence of malrotation
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All of the above
Discussion
The correct answer is (D). Association of an open wound over a fracture dictates that the fracture should be considered an open fracture unless proven otherwise. Fractures that are open should be addressed expeditiously and emergently with irrigation and debridement of the open wound. Repair of the lacerated structures, if any, and treatment of the fracture (either with closed reduction and percutaneous pin fixation or with open reduction/internal fixation depending on the location, nature of fracture, and degree of comminution) should then be addressed. Should the injury be closed, then the degree of angulation and the presence of malrotation are essential features in decision-making. If the patient presents with malrotation, which is extremely uncommon, the fracture needs to be reduced and either pinned percutaneously or fixed internally in an open manner irrespective of the degree of angulation. In terms of angulation, these fractures are best measured on a true lateral view. A line is drawn along the axis of the distal fragment, and a line is also drawn along the axis of the proximal fragment. The angle formed by these two lines depicts the angulation at the fracture site. Any angulation in excess of 30 to 40 degrees necessitates manipulative reduction followed by either splinting or percutaneous pin fixation. A common error is to measure the angulation in an oblique view, which usually gives an erroneous impression, with magnification of the angulation leading to unnecessary manipulations.
North American literature suggests that angulation in excess of 30 to 40 degrees should be manipulated closed. This is done utilizing the Jahss maneuver in which the fracture site is anesthetized with the instillation of a hematoma block, the metacarpophalangeal joint is flexed, and pressure is applied on the metacarpal head through the proximal phalanx so as to extend the metacarpal head and align it with the metacarpal shaft. The patient’s hand is then immobilized in an ulnar gutter splint, holding the finger in the correct position with the MP joint flexed 80 to 90 degrees and the IP joints straight. This is called the intrinsic plus position, and the splint usually extends onto the distal part of the forearm. Angulations of less than 30 degrees do not need manipulation and can simply be splinted and followed with radiographs on a weekly basis.
The most common complication encountered after such an injury is:
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Avascular necrosis of the metacarpal head
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Instability of metacarpophalangeal joint
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Malrotation
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Angulation apex dorsal at the fracture site
Discussion
The correct answer is (D). In most circumstances, these fractures unite in the position in which they presented in if no treatment had been carried out. This is usually an apex dorsal deformity, and in rare circumstances, patients may complain of a palmar prominence of the metacarpal head, especially during power gripping activities. Despite this angulation, most patients have very satisfactory clinical outcomes with essentially full range of motion. During the recovery period, it is not uncommon for patients to have difficulty achieving complete extension of the metacarpophalangeal joint, which does resolve with the passage of time. However, angulations which are excessive may be associated with a pseudo-claw deformity.
Objectives: Did you learn...?
Identify the radiographic features of a Boxers fracture? Describe complications of this injury?