Which scaphoid fracture pattern carries a high risk of nonunion and AVN, often prompting surgical fixation?

• A. Distal pole fractures.
• B. Waist fractures.
• C. Midshaft fractures.
• D. Proximal pole fractures and displaced fractures.

Answer: (D)

The pattern with the highest risk of nonunion and avascular necrosis is fractures of the proximal pole, especially when they are displaced. The scaphoid’s blood supply comes largely from vessels that enter the bone distally and travel toward the proximal pole. When a fracture occurs at the proximal pole or if a fracture is displaced, this retrograde blood flow can be disrupted, leaving the proximal fragment poorly perfused or avascular. That makes healing difficult and raises the risk of both nonunion and AVN. Because stability and blood flow are both compromised in these cases, surgical fixation is often chosen to restore alignment and provide rigid fixation that supports revascularization and healing.

By contrast, distal pole fractures usually preserve most of the blood supply, and waist or midshaft fractures typically retain better perfusion to the proximal fragment, so the risk of AVN is much lower and nonoperative treatment can be successful if the fracture is nondisplaced.