A patient presents with wrist pain after a fall. X-rays are negative. You palpate the snuffbox and there is mild tenderness. One dominant current practice is to apply a thumb spica splint in all such cases but you suspect this causes too many patients to be immobilized. Can the physical examination help?
There actually have been a large number of studies on this, with one study reviewing 18 separate clinical signs and keeping 7.(Steenvorde 2006) For the sake of consistency though, the examination of this bone for a fracture can be thought of in the same way we examine any other bone for a fracture.
First, have the patient point to the area of maximal pain. Are they pointing at the scaphoid?
Second, remember that this bone has multiple sides. Don’t just palpate the snuffbox. You can feel the scaphoid tubercle on the volar side at the base of the thumb metacarpal. Palpation is 87% sensitive and 57% specific for a fracture, which generates a better likelihood ratio than snuffbox tenderness, which is only 40% specific.(Steenvorde 2006)
Because this bone is superficial, feel for any swelling. If you find snuffbox swelling with a “fall on outstretched hand” mechanism, fracture is the only pathology that plausibly accounts for the finding, if it is isolated. Swelling is found in 61% of scaphoid fractures.
Finally, stress testing can be helpful in the fracture examination. Axial compression, resisted supination, and ulnar deviation can all be signs of a fracture if they isolate pain to the area of the scaphoid. False positive will occur with other injuries so we are not just looking for pain, but localizing scaphoid pain.
Take Home Points:
-Have the patient point to the maximally painful area
-Palpate the scaphoid tubercle in addition to the snuffbox for suspected scaphoid fractures
-Check for swelling in the snuffbox
-Provide axial, supination, and ulnar deviation stress tests