Most Common Mechanism for Scaphoid Fracture
The most common mechanism for a scaphoid fracture is a fall onto an outstretched hand with the wrist in extreme dorsiflexion. 1, 2
Mechanism of Injury
- Scaphoid fractures typically occur when a force is applied to the palmar aspect of the wrist while it is in extreme dorsiflexion, most commonly during a fall onto an outstretched hand 1
- This mechanism creates a combination of forces that makes the scaphoid bone particularly susceptible to fracture 1
- The scaphoid is the most commonly fractured carpal bone, representing approximately 11% of all upper extremity fractures 3
Epidemiology and Occurrence
- Scaphoid fractures show a bimodal distribution, with higher rates in younger (<18 years) and older (>65 years) populations 4
- In younger, more active patients, these fractures commonly occur during sports activities or vehicular accidents 4
- In older, less active patients, fractures typically result from falling onto an outstretched hand from ground level 4
- In children, scaphoid fractures are relatively rare, representing only 0.34% of all pediatric fractures and 0.45% of upper limb fractures in children 5
Clinical Presentation and Diagnosis
- Patients with scaphoid fractures typically present with pain and tenderness in the anatomic snuffbox following a fall on an outstretched hand 3
- Initial evaluation should include standard wrist radiographs with a dedicated "scaphoid view" 6
- If initial radiographs are negative but clinical suspicion remains high, the American College of Radiology recommends proceeding directly to MRI without IV contrast 6
- MRI without IV contrast has the highest sensitivity (94.2%) and specificity (97.7%) for diagnosing scaphoid fractures 6
Fracture Characteristics and Complications
- Most scaphoid fractures in children involve the distal third of the bone and are typically undisplaced 5
- Displaced fractures (>1 mm) have a significantly higher risk of complications, with a 55% incidence of nonunion and 50% rate of avascular necrosis 7
- The anatomical location, configuration, and vascular supply of the scaphoid predispose it to complications following fracture 2
- Displaced fractures that heal spontaneously often require prolonged immobilization and are associated with a greater incidence of painful malunion 7
Treatment Considerations
- Non-displaced fractures are typically treated with cast immobilization 3
- Operative treatment should be considered for displaced fractures or non-displaced fractures in young active patients, using internal fixation with cannulated screws 3
- Early detection and appropriate treatment are crucial for favorable outcomes in scaphoid fractures 3
- CT imaging is particularly useful for pre-operative planning to determine fracture location and fragment displacement 3