EPL dysfunction post wrist fracture

[Heath Edwards]

Hi Steve,

I had a case recently where a patient had EPL dysfunction 2 months post distal radius fracture. Non surgical treatment of the distal radius fracture. The EPL was intact, as were the remaining wrist tendons. I did however notice that the PIN was focally thickened when compared to the opposite side at the wrist and measured 1.1mm. Could at neuropathy of the PIN at the wrist cause an EPL dysfunction?

Cheers
Heath

[Stephen Bird]

Hi Heath,
This is a good question,
EPL dysfunction following a distal radius fracture is most commonly associated with the Listers tubercle being involved in the fracture leaving an abrasive edge for the tendon to pass around. This often leads to tendon rupture over time.
I presume the part of the PIN you have seen swollen is the distal part deep to the compartment 4 tendons.
Swelling of this part of the PIN is associated with dorsal carpus pain, however in my hands I find it a very difficult diagnosis as the distal PIN seems to have a wide variety of sizes when you scan normal volunteers and also the contralateral side. I find this a very difficult ultrasound diagnosis and would be more inclined to be guided by the clinical rather than the sonographic evidence.
I don’t see how EPL function can be linked to the distal PIN as it has already provided the motor function proximal to this level. If it was swollen at the Arcade of Frohse this might make sense. But if this was the case I would expect some clinical weakness of supination, ECU, EDC, EDM and APL function.
What did the muscle belly look like when compared to the other side?

Steve

[Heath Edwards]

Hi Steve

I’ve also seen EPL dysfunction and rupture with long volar plate screws however the EPL was intact with no collagen changes at Listers tubercle.
The swollen PIN is indeed at the level of the wrist deep to compartment 4. I knew that the EPL was innervated by the PIN proximally however at the Arcade of Frohse the PIN was within normal limits. Hence the confusion.
The muscle belly was similar to the other side with no fatty atrophic change.

Is it possible that when the patient fell fracturing the distal radius an impact injury proximally has caused a post traumatic neuritis and the EPL dysfunction is a result? That’s me just speculating

Cheers

Heath

[Stephen Bird]

I guess that is possible indeed,
We have no sonographic evidence, but don’t let imaging get in the way of a good clinical diagnosis.
I wonder if nerve conduction tests can isolate EPL motor innervation?

Steve

[Author]

Posts