Which of the following scaphoid fracture patterns has the highest nonunion/AVN risk and often requires surgical fixation?

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

Answer: (C)

The problem hinges on how scaphoid blood supply affects healing after a fracture. Blood reaches the scaphoid mostly from distal to proximal, so a fracture can cut off its own blood flow, with the impact depending on where the break is and whether the piece is displaced.

Fractures at the proximal pole are most vulnerable because they rely on retrograde blood flow, so disruption here greatly increases the risk of avascular necrosis. If the fracture is displaced, the disruption of vascular channels is even more pronounced, markedly raising nonunion and AVN risk. Because of this, these patterns often require surgical fixation to realign the bone, stabilize the fragment, and optimize blood supply for healing.

In contrast, distal pole fractures have better residual blood supply and lower AVN risk, waist fractures, while common, also heal reasonably but carry some nonunion risk depending on displacement, and non-displaced fractures generally heal well with casting.

So, the pattern with the highest risk of nonunion and AVN, and that often needs surgical fixation, is the proximal pole fracture when displaced.