Wrist & Hand: Scaphoid fractures

Question 1

what is the most commonly fractured carpus?

Answer 1

scaphoid

Question 2

how is the scaphoid bone divided?

Answer 2

3 parts:
proximal pole
waist
distal pole

Question 3

branches of which artery supply the scaphoid bone?

Answer 3

radial artery - dorsal branch of the radial artery

Question 4

where does the dorsal branch of the radial artery enter the scaphoid bone and what is the clinical significance of this?

Answer 4

distal pole and travels in a retrograde fashion towards the proximal pole. fractures can compromise the blood supply leading to avascular necrosis (AVN)

Question 5

fractures where on the scaphoid bone are at higher risk of AVN?

Answer 5

the more proximal the fracture the higher the likelihood AVN

Question 6

common mechanism of injury for scaphoid fracture

Answer 6

trauma

Question 7

clinical features of scaphoid fractures

Answer 7

sudden wrist pain 
may be bruising 
tenderness in flood of anatomical snuffbox 
pain on palpating scaphoid tubercle 
pain on telescoping of the thumb

Question 8

what is another differential for pain on telescoping of the thumb?

Answer 8

osteoarthritis of the 1st metacarpal base

Question 9

DDx for scaphoid fractures

Answer 9

distal radius fracture
alternative carpal bone fracture
fracture of base of 1st metacarpal 
ulnar collateral ligament injury 
wrist sprain 
De Quervains tenosynovitis

Question 10

what investigations are done for a ?scaphoid fracture?

Answer 10

plain radiograph - scaphoid series - AP, lateral and oblique views

Question 11

is a fracture always detected on initial radiographs?

Answer 11

no - especially when they are undisplaced
if there is sufficient clinical suspicion patient should have wrist immobilised in a thumb splint and repeat plain radiographs in 10-14 days

Question 12

what is done when the repeat imaging is negative but clinical findings are still in keeping with scaphoid fracture?

Answer 12

MRI scan of the wrist - definitive investigation

interim treatment is as for a fracture

Question 13

how are undisplaced scaphoid fractures managed?

Answer 13

strict immobilisation in plaster with spica thumb splint
Undisplaced fractures of proximal pole have high risk of AVN and surgical treatment may be advocated - particularly if dominant hand of working-age patient

Question 14

how are displaced fractures managed?

Answer 14

fixed operatively

percutaneous variable-pitched screw placed across the fracture site to compress it

Question 15

complications of scaphoid fractures

Answer 15

AVN - 30% of cases - especially proximal

non-union - failing to heal properly most commonly due to poor blood supply

Question 16

what happens to scaphoid fractures which are undiagnosed of inappropriately managed?

Answer 16

common

managed with internal fixation and bone grafts