9.23 Scaphoid (Carpal Navicular) Fracture

agk’s Library of Common Simple Emergencies

Presentation

The patient (usually 14-40 years old) fell on an outstretched hand, with the wrist held rigid and extended, and now complains of pain, swelling, and decreased range of motion in the wrist, particularly on the radial side. Physical examination discloses no deformity, but pain with motion and palpation and often swelling, especially in the anatomic snuff box (on the radial side of the wrist, between the tendon of the extensor pollicis longus and the tendons of the abductor pollicis longus and extensor pollicis brevis). A good sign is axial loading along the proximal phalanx of the thumb, eliciting pain at the base.

What to do:

• Apply ice and a temporary splint, check for distal sensation and movement and other injuries; and order x rays of the wrist, with special attention to the scaphoid bone and its fat pad.
• Regardless of whether a scaphoid fracture shows on x ray, splint or cast the wrist in extension, with the thumb out in opposition, and immobilized to its interphalangeal joint.
• Explain to the patient the frequent difficulty of visualizing scaphoid fractures on x rays, the frequent difficulty in healing of scaphoid fractures due to variable blood supply, and the resultant necessity of keeping this splint or cast in place for a week.
• Arrange for re-evaluation and further treatment within the next few days.

Discussion

Because fractures of the scaphoid bone are common, because they are often invisible on x ray until weeks later, because the blood supply to the fractured area may be tenuous and non-union or avascular necrosis likely, and because the resultant pain and arthritis may severely limit hand function, it is prudent practice to splint or cast all potential scaphoid fractures with a thumb spica until orthopedic re-evaluation in 1-2 weeks.

References:

• Waeckerle JF: A prospective study identifying the sensitivity of radiographic findings and the efficacy of clinical findings in carpal navicular fractures. Ann Emerg Med 1987;16:733-737.

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