Scaphoid fractures account for nearly three-quarters of carpal injuries and result from violent hyperextension of the wrist.
Fracture of the scaphoid:
- should be suspected in any fall on an outstretched hand
- is more common in young adults than in children and the elderly
The scaphoid bridges the proximal and distal rows of carpal bones and is subject to severe loading from forced carpal movement and compression when the wrist is abruptly hyperextended.
Three fractures sites are recognised:
- through the waist:
- the most narrow part of the scaphoid
- most common
- through the proximal pole
- through the tubercle
The condition was once more commonly known as "Chauffeur's fracture" since it often resulted when a car backfired whilst still holding the starting crank handle.
Key points (1):
- the most sensitive clinical sign of scaphoid fracture is anatomical snuffbox tenderness - however this clinical sign has low specificity (ie, a high rate of false positives)
- the first line investigation is a four-view scaphoid radiograph series - however negative radiography does not rule out fracture
- the sensitivity of scaphoid radiographs in the first week after injury is only 80%, meaning that negative radiographs cannot reliably rule out a fracture
- for patients with a clinically suspected scaphoid fracture but normal radiographs
- management is wrist immobilisation and further imaging (preferably MRI)
- scaphoid fractures that are "missed" are:
- more likely to develop a non-union, and
- potentially post-traumatic osteoarthritis of the wrist
Reference:
- Berber O et al.Fractures of the scaphoid. BMJ 2020;369:m1908 doi: 10.1136/bmj.m1908