Populations and Risk Factors
- Individuals sustaining FOOSH (fall on outstretched hand) injuries, particularly with impact on the thenar eminence
- Athletes in contact sports, skateboarding, cycling, snowboarding
- Young adults (peak incidence ages 15-30)
- Frequently misdiagnosed as a "simple wrist sprain" — this is the most dangerous misdiagnosis because delayed treatment increases AVN risk
- Proximal pole fractures have the highest AVN risk (blood supply enters distally)
Causes and Pathophysiology
- Mechanism: FOOSH transmits impact force from the capitate through the scaphoid to the radius. The scaphoid bridges the proximal and distal carpal rows and bears the brunt of axial loading
- Precarious blood supply: Blood enters the scaphoid primarily through the distal pole and flows proximally via intraosseous vessels. Proximal pole fractures disrupt this supply, creating high AVN and nonunion risk
- Radiographic invisibility: Undisplaced fractures may not appear on standard radiographs for up to two weeks — MRI or bone scan is needed for early detection. Persistent snuffbox tenderness must be treated as fracture until proven otherwise
- Displaced fractures disrupt blood flow entirely, accelerating AVN and secondary degenerative joint disease (scaphoid nonunion advanced collapse — SNAC wrist)
Signs and Symptoms
- Deep pain at the lateral (radial) wrist and exquisite tenderness in the anatomical snuffbox
- "Clamp sign": patient instinctively grasps the scaphoid between thumb and index finger to splint the injury
- Pain and limitation with wrist extension
- Pain with resisted supination or axial loading of the thumb (scaphoid compression test)
- Swelling localized to the radial aspect of the wrist distal to the radial styloid
- Red flags: Persistent snuffbox pain after FOOSH must be treated as fracture until imaging rules it out — even if initial X-rays are negative; refer for MRI or bone scan if pain persists beyond 10-14 days
CMTO Exam Relevance
- CMTO Appendix category A1 (MSK conditions)
- Essential tests: snuffbox tenderness (nearly 100% sensitivity), scaphoid compression test, Watson (shift) test
- Persistent snuffbox pain after trauma must be treated as fracture until imaging rules it out
- Proximal pole fractures carry the highest AVN risk due to the retrograde blood supply pattern
- Immobilization is typically 12+ weeks (longer than most fractures) because of slow healing from poor blood supply
Massage Therapy Considerations
- Acute phase: Locally contraindicated until clinical union is achieved (typically 12+ weeks)
- During casting: Massage shoulder and neck for compensatory tension from cast carriage
- Post-immobilization: Restore joint pliability, stretch adhesions, address disuse atrophy in forearm flexors, extensors, and thenar muscles
- Focus: Stretch wrist flexors and transverse carpal ligament to restore the transverse arch of the hand. Restore accessory glide of the scaphoid on the radius
- Differential awareness: Distinguish from De Quervain tenosynovitis (Finkelstein positive, snuffbox tenderness may overlap) and radiocarpal instability
Key Takeaways
- The scaphoid is the most commonly fractured carpal bone (70% of carpal fractures), typically from FOOSH, with high AVN risk due to precarious retrograde blood supply
- Persistent snuffbox pain after trauma must be treated as fracture until imaging rules it out. Fractures are often invisible on X-ray for up to two weeks
- Locally contraindicated until clinical union (typically 12+ weeks). During casting, massage shoulder and neck for compensatory tension
- Post-immobilization: restore joint pliability, stretch adhesions, and restore the transverse arch of the hand
- Anatomical snuffbox tenderness has nearly 100% sensitivity for scaphoid fracture