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Ortho - Hand > Wrist Trauma - Scaphoid Fracture > Flashcards

Wrist Trauma - Scaphoid Fracture Flashcards

1
Q

What is the most commonly fractured carpal bone?

A

The Scaphoid

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2
Q

What is the incidence of scaphoid fractures in wrist injuries?

A

Scaphoid fractures account for 15% of acute wrist injuries

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3
Q

What is the incidence of scaphoid fractures in relation to their location on the scaphoid?

A
  • waist = 65%
  • proximal third = 25%
  • distal pole = 10%
    • this is the most common location of fracture in kids due to location of the ossification centre
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4
Q

What is the most common mechanism of injury in scaphoid fractures?

A

The most common mechanism of injury in scaphoid fractures is axial load across wrsit that is hyper-extended and radially deviated.

  • this is most commonly in sports
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5
Q

What is the associated condition with scaphoid fractures?

A

SNAC wrist (Scaphoid Nonunion Advanced Collapse)

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6
Q

What is the prognosis with Scaphoid fractures, in respect to AVN rates?

A
  • Incidence of AVN with location:
    • proximal 5th = 100% AVN
    • proximal 3rd = 33%
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7
Q

What percentage of the scaphoid is articular cartilage?

A

>75%

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8
Q

What is the blood supply to the scaphoid?

A
  • The major supply to the scaphoid:
    • dorsal carpal branch (branch of the radial artery)
    • enters the scaphoid in a non articular ridge along the dorsal surface and supplies 80% of the scaphoid via retrograde blood flow
  • The minor supply to the scaphoid:
    • superficial palmar arch (branch of the volar radial artery)
    • enters the distal tubercle and supplies 20% of the scaphoid
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9
Q

What is the motion of the scaphoid with movement of the wrist?

A
  • both intrinsic and extrinsic ligaments attach and surround the scaphoid
  • the scaphoid flexes with wrist flexion and radial deviation
  • the scaphoid extends with wrist extension and ulnar deviation
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10
Q

What are 3 physical exam findings with scaphoid injury?

A
  1. anatomic snuffbox tenderness
    1. see snuff box picture. Radial border of EPB and ulnar border of EPL tendon.
  2. scaphoid tubercle tenderness volarly
    1. See photo.
  3. pain with resisted pronation
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11
Q

What are the recommended radiographs of the scaphoid, and what do you do if they are negative?

A
  • AP & LAT
  • Scaphoid View
    • wrist in 30deg extension and 20deg of ulnar deviation
  • 45 deg pronation view
  • If films are negative and there is a strong clinical suspicion for fracture, you should immobilize and repeat radiographs in 14-21 days.
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12
Q

What are the indications for non operative management of scaphoid fractures?

A
  • Stable, nondisplaced fracture (majority)
  • In patients that have normal xrays, but high index of clinical suspicion. Immobilize for 12-21 days, then reassess.
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13
Q

When do you start immobilization of scaphoid fractures?

A

Start early - non union rates increase with delay to immobilization, of >4 weeks after injury.

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14
Q

What type and length of casting should be applied in scaphoid fractures?

A
  • long arm spica vs short arm casting is contraversial with no definitive consensus to date
  • duration of casting depends on location of fracture
    • distal-waist - 3 months
    • mid-waist - 4 months
    • proximal third - 5 months
    • athletes should not return to play until imaging shows a healed fracture
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15
Q

What technique can assist with delayed unions of scaphoid fractures?

A

You can augment with pulsed elctromagnetic field (studies show benefit in delayed union)

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16
Q

What is the union rate of scaphoid fractures?

A

Fractures with <1mm displacement have 90% union rate

17
Q

What are the indications for operative fixation of scaphoid fractures?

A
  1. unstable scaphoid fractures
  2. to allow fast time to union, faster return to work/sport (similar total cost when compared to casting)
18
Q

What are 8 indications that a scaphoid fracture is unstable?

A
  1. proximal pole fractures
  2. displacement >1mm
  3. 15deg humpback deformity
  4. radiolunate angle >15deg (DISI)
  5. intrascaphoid angle >35deg
  6. scaphoid fractures associated with perilunate dislocation
  7. comminuted fractures
  8. unstable vertical or oblique fractures
19
Q

What is the indication for the dorsal approach to fixation of the scaphoid, and list one specific consideration that must be undertaken in this approach.

A
  • indicated in proximal pole fractures
  • care must be taken to preserve the blood supply when entering the dorsal ridge by limiting exposure to the proximal half of the scaphoid.
20
Q

What is a major risk with percutaneous screw fixation of scaphoid fractures?

A

screw penetration of subchondral bone

21
Q

What is the indication of the volar approach in scaphoid fracture fixation, what exposure does it allow, and what is it’s interval?

A
  • indcated in waist and distal pole fractures and fractures with humpback flexion deformities
  • allows exposure over the entire scaphoid
  • uses the interval between the FCR and radial artery
22
Q

Other than the volar and dorsal approaches to the scaphoid, what else has been described?

A

arthroscopic assisted approach

23
Q

What is the described fixation of scaphoid fractures?

A

rigidity is optimized by long screw placed down the central axis of the scaphoid

24
Q

What should be performed if there is evidence of impaction osteoarthritis between the radial styloid and the scaphoid?

A

Radial styloidectomy

25
Q

What are 3 treatment options for scaphoid nonunions?

A
  1. inlay (Russe) bone graft
  2. interposition (Fisk) bone graft
  3. vascular bone graft from radius
26
Q

What is the indication to use an inlay graft for scaphoid fracture fixation?

A
  • nonunion where there is minimal and there is no adjacent carpal collapse or excessive deformity (humpback scaphoid)
27
Q

What is the union rate of scaphoid non union fractures treated with inlay bone graft?

A

92% union rate

28
Q

What is the indication and technique for interposition (Fisk) bone graft in scaphoid fractures?

A
  • Scaphoid non union where there is adjacent carpal collapse and excessive flexion deformity (humpback scaphoid).
  • an opening wedge graft that is designed to restore scaphoid length and angulation
29
Q

What is the union rate of interposition graft in scaphoid non union fractures?

A

72-95% union

30
Q

What is the indication and technique for vascular bone graft in scaphoid fractures?

A
  • good option for people with AVN of the proximal pole confirmed on MRI (gaining popularity)
  • 1-2 intercompartemental supraretinacular artery (branch of radial artery) is harvested to provid vascularized graft from the dorsal aspect of the distal radius

Ortho - Hand (2 decks)

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