Which fracture is associated with a high risk of avascular necrosis?

• A. Scaphoid fracture
• B. Colles fracture
• C. Smith fracture
• D. Bennett fracture

Answer: (A)

Fractures can cause avascular necrosis when they disrupt the blood supply to the bone. The scaphoid has a unique arterial pattern: blood mainly enters from vessels at the distal pole and travels proximally in a retrograde fashion. If the scaphoid is fractured, especially in the proximal third, the proximal fragment can lose its blood supply. Without adequate perfusion, the proximal scaphoid tissue can die, leading to avascular necrosis and poor healing or nonunion. This makes scaphoid fractures particularly prone to AVN compared with other common wrist fractures, where blood flow to the bone is less likely to be interrupted.