For patients with a suspected fracture in the wrist but negative initial X-rays, which is a critical reason for a thumb spica splint?

• A. To prevent wrist swelling
• B. To immobilize the hand for better healing
• C. To prevent avascular necrosis
• D. To reduce pain immediately

Answer: (C)

In the context of a suspected wrist fracture, especially regarding the scaphoid bone, the application of a thumb spica splint serves several important purposes. One of the critical reasons is to prevent avascular necrosis.

The scaphoid bone has a unique blood supply that can be compromised if there is a fracture, especially at the proximal pole, which is the part of the bone that is most prone to avascular necrosis due to insufficient blood flow. When a fracture goes unrecognized in initial X-rays, immobilizing the wrist and thumb with a spica splint can help stabilize the fracture and maintain an optimal position for healing, thereby guarding against the risk of avascular necrosis.

This protective immobilization is crucial, particularly in scenarios where the scaphoid fracture may not be evident on initial imaging, as prompt and appropriate treatment minimizes the risk of complications that can arise from delayed treatment of such fractures.