(See also Overview of Fractures.)
The scaphoid is the most commonly injured carpal bone. Scaphoid fractures usually result from wrist hyperextension, typically during a fall on an outstretched hand. They can disrupt the blood supply to the proximal scaphoid. Osteonecrosis is thus a common complication, even when initial care is optimal, and can cause disabling, degenerative arthritis of the wrist.
Symptoms and Signs
The radial side of the wrist is swollen and tender. If patients have these symptoms, scaphoid fracture should be considered. More specific signs include
The anatomic snuffbox is palpated just distal to the radius between the extensor pollicis longus, extensor pollicis brevis, and abductor pollicis longus tendons.
Diagnosis
Initially, plain x-rays (anteroposterior, lateral, and oblique views) are taken but are often normal. In a recent meta-analysis, false-negative rates in most series ranged from 6 to 18% for plain x-rays (1).
If x-rays are normal but a fracture is still suspected, MRI can be done. MRI is being increasingly used to diagnose scaphoid fractures because it is more accurate than CT or bone scanning in the acute setting (1).
If a fracture is suspected clinically and imaging is nondiagnostic, it is treated presumptively as a fracture and a thumb spica splint is applied. The patient should be re-examined 1 week after injury. If the patient is still in pain or if the wrist is tender when examined 1 week after injury, repeat plain x-rays are taken.
Diagnosis reference
-
1. Carpenter CR, Pines JM, Schuur JD, et al: Adult scaphoid fracture. Acad Emerg Med 21 (2):101–121, 2014. doi: 10.1111/acem.12317
Treatment
Key Points
-
Scaphoid fractures usually result from wrist hyperextension, typically during a fall on an outstretched hand.
-
These fractures can disrupt the blood supply to the proximal scaphoid; thus, osteonecrosis is a common, sometimes disabling complication.
-
Take anteroposterior, lateral, and oblique x-rays; if imaging is normal or nondiagnostic but clinical findings suggest a scaphoid fracture, do MRI or immobilize with thumb spica splint and arrange for repeat x-rays in 1 week.
