Diagnosis of scaphoid fractures. Are plain radiographs reliable?

Clinical Scenario

It’s a busy wednesday morning in ED. 

A 18 yo guy presents with the right hand upraised and dressed. 

In the other hand he has a bundle of X ray.   

“About ten days ago, it was a Saturday night, I was with my new girl-friend. Hitting a punch bag as hard as possible I felt pain to my right wrist. My doctor ordered wrist X ray. It’s not broken, he says, but I’m very afraid, when I move the wrist  it pains me so much”.

On clinical examination there is snuff box tenderness, the axial loading maneuvre on the thumb is positive (see previous post). 

The emergency phisician takes an accurately look at the X rays. They are of high quality, the study had 4 views of the scaphoid, there’s no evidence of irregularity of cortex, the scaphoid fat pad seems normal.

“Repeat X-ray” orders the doctor….

Conclusion 

Pretest probability of scaphoid fracture, in a  guy with tipical history and snuff box tenderness (see the previous post) with initial negative X-Ray, is about 25% . 

The fat pad sign has a poor value (if you don’t know it click here), on the other hand a 10-14 day follow up X rays is a good idea but is not sufficiently accurate, post test probability doesn’t change even if a second X ray resultes negative.  

And now? Bone scan, US, CT or RMN?

To be continued……

   

Bibliography 

CR Carpenter

Adult scaphoid fracture

Acad Emerg med 2014 21:102-121 

CA Germann

Risk management and avoiding legal pitfalls in the emergency treatment of high-risk orthopedic Injuries

Emerg Med Clin N Am 2010 28: 969-996 

Ciro Paolillo