Scaphoid Fracture
The Scaphoid is the most commonly fractured carpal bone (60-70%). It is notorious for non-union and avascular necrosis (AVN) due to its unique retrograde blood supply.
1. Clinical Features
- Pain: Tenderness in the Anatomical Snuffbox.
- Mechanism: FOOSH (Fall On Outstretched Hand).
- X-ray: Often negative initially. If suspected, treat as a fracture and repeat X-ray in 2 weeks, or get an MRI/CT.
2. The Blood Supply Problem
Blood enters the scaphoid from the distal end and flows proximally. Therefore:
- Distal Pole fractures: Heal well.
- Waist fractures: Moderate risk.
- Proximal Pole fractures: Very high risk of AVN (Avascular Necrosis) as they lose blood supply.
3. Management
- Conservative: Scaphoid Cast (Glass holding position) for 8-12 weeks.
- Surgical: Herbert Screw fixation (headless screw that is buried inside the bone).
25 Practice MCQs
Q1. The most common site of scaphoid fracture is:
Answer: A). The middle part of the bone.
Q2. Tenderness in the "Anatomical Snuffbox" suggests:
Answer: B). Classic clinical sign.
Q3. Why is the proximal pole prone to Avascular Necrosis (AVN)?
Answer: A). A fracture at the waist cuts off blood to the proximal part.
Q4. If X-rays are normal but clinical suspicion is high, you should:
Answer: A). Occult fractures become visible as bone resorbs at the fracture line.
Q5. The specialized screw used for scaphoid fixation is:
Answer: B). It can be buried in the cartilage without protruding.
Q6. "Glass holding position" refers to:
Answer: A). Wrist extended, thumb abducted (like holding a glass).
Q7. Non-union of the scaphoid can lead to:
Answer: A). A pattern of progressive arthritis.
Q8. The scaphoid links which two carpal rows?
Answer: A). Hence it is subjected to high shear forces.
Q9. Healing time for scaphoid fractures is typically:
Answer: B). Due to poor blood supply and intra-articular nature.
Q10. Preiser's Disease is:
Answer: A). Rare condition (Kienbock's is Lunate AVN).
Q11. The floor of the Anatomical Snuffbox is formed by:
Answer: A). Tenderness here hits the scaphoid directly.
Q12. CT scan is preferred over MRI for:
Answer: A). MRI is better for early occult fracture or AVN (blood supply).
Q13. Russe bone grafting is used for:
Answer: A). Inlay graft technique.
Q14. Which view is specific for Scaphoid?
Answer: A). Elongates the scaphoid profile.
Q15. Scaphoid fracture is rare in:
Answer: A). Children break the distal radius physis; Elderly break the distal radius metaphysis (Colles). Scaphoid is for young adults.
Q16. Terry Thomas sign indicates:
Answer: A). Ligament injury often associated with wrist trauma.
Q17. Humpback deformity is:
Answer: A). Leads to carpal instability (DISI).
Q18. Pulsed Electromagnetic Field (PEMF) therapy is used for:
Answer: A). Adjunct for non-unions.
Q19. Percutaneous fixation is possible for:
Answer: A). Allows faster rehab than casting.
Q20. The tubercle of scaphoid is palpable:
Answer: A). Important landmark.
Q21. Which artery supplies the scaphoid?
Answer: A). Dorsal carpal branch.
Q22. Proximal row carpectomy (removing proximal row) is a salvage for:
Answer: A). Maintains some motion compared to fusion.
Q23. Watson's Test (Scaphoid Shift Test) checks for:
Answer: A). Provocative test causing a "clunk".
Q24. Immobilization should include the thumb (Spica)?
Answer: A). Evidence is mixed, but most surgeons use a Thumb Spica cast.
Q25. Return to contact sports is allowed:
Answer: A). Risk of re-fracture is high.
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