Scaphoid Fractures- Hand Surgeon Perspective

1. General Overview & Epidemiology

The scaphoid is the most commonly fractured carpal bone, accounting for approximately 60–70% of all carpal fractures and 11% of all hand fractures.

Demographics: Most prevalent in young, active males  (2 :1 male : female) (ages 15–30). It is rare in children and the elderly, where the distal radius is more likely to break first.

Mechanism: Typically a fall on an outstretched hand (FOOSH) with the wrist in extension (>90°) and radial deviation.

 2. Relevant Anatomy

• The scaphoid's anatomy is its destiny. It is a boat-shaped bone that bridges the proximal and distal carpal rows. Complex 3-dimensional structure described as resembling a boat, skiff, and twisted peanut oriented obliquely from extremity's long-axis (implications for advanced imaging techniques) largest bone in proximal carpal row .

• > 75% of scaphoid bone is covered by articular cartilage

• articulates with radius, lunate, trapezium, trapezoid, and capitate

·       Anatomic location

         percentage of fractures by scaphoid anatomic location

• waist -65%

• proximal third - 25%

• distal third - 10%

  • Historically the distal pole is most common location in pediatrics due to ossification sequence, however more recently waist fractures have become most common 

• Blood Supply: Crucially, the blood supply is retrograde. The branches of the radial artery enter the bone at the distal pole or waist and travel back to the proximal pole.

• Vulnerability: Because of this retrograde flow, fractures at the "waist" or "proximal pole" often cut off the blood supply to the proximal fragment, leading to a high risk of Avascular Necrosis (AVN).
  

 3. Clinical Presentation & Physical Examination

Clinical Complaints:

• Dorsoradial wrist pain.

• Weakness in grip and pinch.

• The "sprained wrist" that doesn't get better.

Physical Examination Findings:

1. Anatomical Snuffbox Tenderness: High sensitivity (90%) but lower specificity.

2. Scaphoid Tubercle Tenderness: Palpated on the volar aspect of the wrist.

3. Thumb Axial Compression Test: Pain when pressure is applied along the long axis of the thumb.

4. Watson Shift Test: May be positive if associated ligamentous injury is present.

4. Radiological Findings

·       Initial X-rays can be negative in up to 20 -30 % of cases. repeat radiographs in 14-21 days

• Standard Series: PA, Lateral, Oblique (semi-pronated (45°)) , and the Scaphoid View (PA with 30° ulnar deviation and extension).

• Bone scan: Occult fractures in acute setting . Specificity of 98%, and sensitivity of 100%, PPV 85% to 93% when done at 72 hours

• MRI: The Gold Standard for diagnosing occult fractures (those not visible on X-ray) and assessing the vascularity of the proximal pole. approach 100% for occult fractures

• CT Scan: Best for assessing fracture displacement, angulation (humpback deformity), and union status during follow-up.

5. Classification Systems

·       The most widely used is the Herbert Classification, which focuses on stability:

• Mayo Mayo classification (based on location of fracture line) 

• Russe Classification (based on fracture pattern)

6. Treatment Strategies

Non-Surgical Treatment

• Indications: Nondisplaced (distal pole or waist) stable fractures.

• Management: Long-arm or short-arm Thumb Spica Cast. The inclusion of the thumb and the duration (typically 6–12 weeks) remain debated, but immobilization is key. scaphoid fractures with <1mm displacement have union rate of 90%

Surgical Treatment

• Indications: Displaced fractures (>1mm), proximal pole fractures (due to AVN risk), unstable patterns, or athletes requiring early return to play.

• Methods:

            Percutaneous Screw Fixation: Minimally invasive using a headless compression screw (e.g., Herbert screw).

      Open Reduction Internal Fixation (ORIF): Necessary for displaced fractures or those requiring bone grafting.

• indications

  • significantly displaced fracture patterns

  • 15° scaphoid humpback deformity

  • radiolunate angle > 15° (DISI)

  • intrascaphoid angle of > 35°

  • scaphoid fractures associated with perilunate dislocation

  • comminuted fractures

  • unstable vertical or oblique fractures

• outcomes

  • accuracy of reduction correlated with rate of union

7. Prognosis and Complications

Prognosis: Good for distal fractures; becomes more guarded as the fracture moves proximally.

Complications:

·       Non-union: Failure to heal, often leading to SLAC Wrist (Scaphoid Lunate Advanced Collapse). 5-10% following immobilization, higher rates for proximal pole fractures. Treatment isvascularized or nonvascularized bone grafting procedures

·       Avascular Necrosis (AVN): Especially common in the proximal pole (Preiser’s disease). 13-50% of all scaphoid fractures

·       Malunion: Often manifests as a "humpback deformity," which alters wrist biomechanics.

·       Subchondral bone penetration with arthrosis due to prominent hardware

·       SNAC wrist (scaphoid nonunion advanced collapse) 

8. Key Points (Summary)

• Suspect it in everyone: If there is snuffbox tenderness after a fall, treat it as a fracture until proven otherwise (the "suspected scaphoid" protocol).

• Proximal = Problem: The more proximal the fracture, the higher the risk of AVN and non-union.

• Vascularity is King: MRI is your best friend for evaluating the health of the bone.

• Follow-up is mandatory: Do not dismiss a patient with a "normal" initial X-ray if clinical suspicion remains high.

Literature & References

1. Rockwood and Green's Fractures in Adults: Detailed section on carpal kinematics and retrograde blood supply.

2. Greene's Operative Hand Surgery: Comprehensive guide on surgical approaches and bone grafting techniques for non-union.

3. Herbert TJ, Fisher WE. Management of the fractured scaphoid using a new type of compression screw. J Bone Joint Surg Br. 1984.

4. Boyer MI, et al. Occult scaphoid fractures. J Hand Surg Am. 2002. (Discusses the role of early MRI).