"I think they broke my wrist. It hurts all the way up my arm."
Responding reflexively, I said I would get a wrist x-ray. Given the odds, I immediately guessed this might be a Colles fracture. The patient said his wrist hurt all over, but pointed specifically to the distal ulna. That's atypical. Not the distal radius?
We would see when the x-ray was done. Then we would know.
The distal ulnar neck fracture was obvious. The break was close to the distal radioulnar joint (DRUJ). Should I be concerned? I ran through my DRUJ checklist:
Is the ulna snuggled in the sigmoid notch? Check.
Is the radioulnar joint line aligned? Check.
Is the ulnar styloid intact? Check.
One view, however, is not enough to be confident that the ulna is in place. I switched screens to the true lateral.
There was no subluxation or dislocation. The radius and the ulna lined up perfectly. Still, should I be concerned?
In emergency medicine, we talk about the rule of the ring: It is difficult to break a ring in just one place, so consider a second fracture whenever there is a bony ring. This is the truth of Maisonneuve fractures of the leg. In this case, I was already sure that it was not a Galeazzi because the distal radius was intact.
Could I be seeing an Essex-Lopresti injury? The patient did say he hurt all the way up the arm. Maybe that interosseous membrane had been torn to shreds. I ordered imaging for the entire forearm, particularly obsessed with the radial head.
The radiocapitellar line was intact. No dislocation. No Essex-Lopresti. It seemed the patient only had a very distal nightstick fracture. Still, it was worth going through the checklist because DRUJ injuries and Essex-Lopresti injuries could have been missed!
Tip to Remember: Injuries to the distal radioulnar joint can be easily missed. Have a RDUJ checklist, and remember the rule of the ring!