Scaphoid Fractures

Carley Vuillermin, MBBS, MPH, FRACS

Scaphoid fractures are often difficult acutely to diagnose due to less severe than expected signs and symptoms. Even in children and adolescents, up to 25% present late with an established nonunion. An accurate diagnosis and treatment to achieve union is imperative to lessen long-term risk of arthritis.

Scaphoid fractures of the distal pole can predominately be treated nonoperatively; proximal pole fractures are essentially treated with fixation; and ORIF of waist fractures is dependent on degree of displacement as discussed below. The more proximal the facture, the higher the risk of avascular necrosis and nonunion from injury.

Scaphoid Waist Fractures

Equipment

Radiolucent hand table
Fluoroscopy
AO headless cannulated screws 2.4 and 3.0 mm (other differential compression screws may also be utilized; this technique will describe one particular device)
- Select a partially threaded screw ensuring no screw threads cross the fracture site (Figure 14-1)
  
  Figure 14-1 ▪ Photograph of headless cannulated scaphoid screw.
Open hand surgery instruments including osteotomes and saw for bone graft harvest uncommonly needed in acute fractures (more common in the nonunion situation)
C-wires (0.35, 0.45, 0.62)
Power drill

Positioning

Supine with arm extended on radiolucent table
Nonsterile tourniquet
Fluoroscopy entering from feet parallel to patient, perpendicular to arm
Regional anesthetic block common

Surgical Approach

Open surgery can be either by volar (retrograde screw) or dorsal (antegrade screw). We will describe volar approach for ORIF and dorsal approach for percutaneous fixation. Either can be used for open or percutaneous reduction and fixation, so take the information here and do what is best for your patient in terms of volar versus dorsal approach and percutaneous versus open reduction and fixation.

Volar approach gives direct view of fracture alignment and reduction and allows assessment of potential volar comminution (may require volar bone grafting). Necessary for percutaneous reduction and fixation in the nonligamentously lax patient (often large, muscular, athletic male).

Open exposure (percutaneous technique will be only distally based part of incision)

Curvilinear incision based at volar radial wrist crease; longitudinal over flexor carpi radialis (FCR) sheath; extending along the radial proximal base of thenars (Figure 14-2).
Dissect through FCR tendon sheath superficial and deep layers (Figure 14-3).
- FCR sheath protects adjacent radial artery.
Extend dissection distally adjacent to thenar origin volar and abductor pollicus longus tendon dorsally exposing radioscaphoid and scaphotrapezial trapezoid (STT) joint capsule.
Open wrist capsule obliquely along radial edge of scaphoid.
Preserve radioscapholunate (RSC) ligament when possible (most acute fractures).
- Usually at the level of a waist fracture.
- If the RSC ligament needs to be partially divided, it should be repaired in closure.
Inspect fracture site; evacuate hematoma.
Open distal STT joint horizontally.
Preserve as much tissue attaching to the tubercle as possible.
Identify proximal pole scaphoid.

Figure 14-2 ▪ Outline of volar approach to scaphoid along flexor carpi radialis (FCR) sheath between radial artery (RA) and palmaris longus (PL) with curvilinear extension along base of thenars.

Figure 14-3 ▪ Deeper dissection with flexor carpi radialis (FCR) tendon and volar branch of radial artery in vessel loops.
Place freer elevator into radioscaphoid joint to elevate scaphoid for reduction and cannulated smooth pin placement (Figure 14-4).
- Avoid using the threaded pin as you do not have the same tactile feedback as smooth wire when reaching the far cortex.
With direct inspection and fluoroscopy, reduce fracture.

Technique

Reduction

Smooth cannulated guide pin is placed into distal pole of scaphoid for planned center:center (1:1) position within the scaphoid (Figure 14-5).
- A small corner of proximal radial trapezium may need to be ronguered or osteotomed away to achieve ideal guide pin position.

Guide pin as joystick aids in anatomic reduction fracture.

Utilizing a 14 g Angiocath to guide the wire can also act as a joystick in the distal fragment (Figure 14-6).
Visualize the fracture reduction.
Extending the wrist over a bolster can correct flexion.
Advance the wire into proximal pole in sequence with imaging (Figure 14-7).

Occasionally a 1.6 mm guide pin placed into the lunate in a neutral alignment can correct the proximal fragment if the fracture is collapsing into DISI deformity.

A mini-open technique on the subcutaneous border of the radius should be utilized to protect the superficial radial nerve.