Written by: Joseph Wu, DO; Edited by: Timothy Khowong, MD, MSEd

Background:

Scaphoid fractures are one of the most common fractures of the carpal bones seen in the emergency department. This injury accounts for 10% of all hand fractures, and 70% of carpal bone fractures. Classically, patients present with this injury after a fall on an outstretched hand (FOOSH), which causes an axial load on a radially deviated and hyperextended wrist. We’re all taught to look out for snuffbox tenderness and to obtain x-rays of the wrist to assess for fracture, however, how good is snuffbox tenderness at ruling in, or ruling out scaphoid fractures? Does a negative x-ray rule out scaphoid fractures? Missing a scaphoid fracture can have devastating long term consequences that include avascular necrosis and osteoarthritis. Treatment of the fracture includes immobilizing the wrist with a splint. However, over-immobilizing a patient’s wrist can have unintended consequences including missed work. The goal of this post is to dig deeper into the nuances of scaphoid fractures and how to more accurately diagnose, and not overdiagnose this tricky fracture.

The scaphoid is the largest carpal bone in the proximal carpal row that receives its majority blood supply (proximal 80%) from the dorsal carpal branch of the radial artery via retrograde blood flow and minor blood supply (distal 20%) from the superficial palmar branch of the radial artery. Fractures that disrupt the blood flow have a high risk of avascular necrosis and nonunion due to the retrograde flow.

The most commonly obtained imaging for scaphoid fractures in the emergency department is the x-ray, which has a sensitivity of 70%. MRI, bone scans, and CT confer much higher sensitivities and specificities, however are often time consuming and can be unobtainable from the ED setting. Point of care ultrasound can be used for diagnosis as well, but is operator dependent and is not routinely done in the emergency department.

Classically, we are taught to assess for snuffbox tenderness on physical exam to evaluate for scaphoid fractures. However, the clamp sign and pain with resisted supination appears to have a greater positive likelihood ratio, supporting the diagnosis of a scaphoid fracture. Resisted supination pain and snuffbox tenderness also confer a low negative likelihood ratio for scaphoid fractures, helping to oppose the diagnosis of scaphoid fracture. Hand and wrist injuries are often debilitating and highly litigious, which skews the provider to be more conservative than liberal with placing a thumb spica splint and following up with orthopedics. However, immobilization of the hand is not without its consequences which can include missing work. With the combination of physical exam, x-ray, and possibly POCUS, we can make a more informed decision when it comes to the management of suspected, or not suspected scaphoid fractures.

References:

1. Bäcker HC, Wu CH, Strauch RJ. Systematic Review of Diagnosis of Clinically Suspected Scaphoid Fractures. J Wrist Surg. 2020 Feb;9(1):81-89. doi: 10.1055/s-0039-1693147. Epub 2019 Jul 21. PMID: 32025360; PMCID: PMC7000269.

2. Carpenter CR, Pines JM, Schuur JD, Muir M, Calfee RP, Raja AS. Adult scaphoid fracture. Acad Emerg Med. 2014 Feb;21(2):101-21. doi: 10.1111/acem.12317. PMID: 24673666.