A scaphoid fracture is a type of wrist fracture, typically arises as a result of a fall onto an outstretched hand (FOOSH). This results in axial compression of the scaphoid, with the wrist hyperextended, and radially deviated. This can also occur during contact sports such as football, or during a road traffic accident due to the patient holding the steering wheel. It is important to examine for scaphoid fractures in anyone presenting with an acutely painful wrist for medico-legal reasons.

Recognising scaphoid fractures is particularly important given the unusual blood supply of the scaphoid bone. Around 80% of the blood supply is derived from the dorsal carpal branch (branch of the radial artery), in a retrograde manner. Interruption of the blood supply risks

avascular necrosis of the scaphoid, with this most commonly complicating proximal injuries.

Causes

• Falling onto an outstretched hand (FOOSH)
• Contact sports: The peak incidence during the autumn is thought to correlate with the start of football and rugby activities at school.

Patients typically present with:

• Pain along the radial aspect of the wrist, at the base of the thumb
• Loss of grip / pinch strength

Signs:

• 1. Point of maximal tenderness over the anatomical snuffbox
  • This is a highly sensitive (around 90-95%), but poorly specific test (<40%) in isolation
• 2. Wrist joint effusion
  • Hyperacute injuries (<4hrs old), and delayed presentations (>4days old) may not present with joint effusions.
• 3. Pain elicited by telescoping of the thumb (pain on longitudinal compression)
• 4. Tenderness of the scaphoid tubercle (on the volar aspect of the wrist)
• 5. Pain on ulnar deviation of the wrist

Clinical examination has a high diagnostic probability (sensitivity 100%; specificity 74%) when [1], [3], and [4] are positive on examination.

Investigations:

• Plain film radiographs should be requested of the wrist in the anterior-posterior view, and lateral view
  • 'Scaphoid views': posterioranterior (PA), lateral, oblique (with wrist pronated at 45º) and Ziter view (PA view with the wrist in ulnar deviation and beam angulated at 20º)
  • The sensitivity in the first week of injury is only 80%
• A CT scan is superior to plain film radiographs, and may be requested in the context of ongoing clinical suspicion, planning operative management, or to determine the extent of fracture union during follow-up.
• MRI is considered the definite investigation to confirm or exclude a diagnosis
  • NICE guidance from 2016 suggested the MRI should be considered the first-line imaging following clinical examination. However, this is still not common practice in the UK
  • however, MRI is much more commonly used second-line when radiographs are inconclusive