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Hi All,
Have a patient at the moment that is stumping me. Healthy and Active but slightly overweight male in his 40's. Works as a sonographer which has been handy in this instance. Experiences a burning aching pain medial to his 1st metatarsal after 500m- 1km of brisk walking pace. He can work a full day doing the rounds in the hospital or shopping in town with no discomfort. Pain only occurs when walking in a straight line and reasonably quickly. Pain has been around for many years (5+) and has limited his activity. On examination ..the area of abductor hallucis muscle belly is larger than his asymptomatic side, and on ultrasound it shows hypertrophy and significant vascularisation. His gait reveals a vertical calcaneal position however significant midfoot instability and MTJ collapse more so on the symptomatic side. There is no tib post issue on testing and u/s. He has rigid 3/4 orthoses which provide significant structure and stability to his midfoot however this has only had moderate success. Abductor hallucis flexes as well as abducts the first ray but wondering if this is a gait related issue or something I maybe missing? Any help would be super :craig:

 

Could be a peroneus longus problem? As it functions to stabilize the first ray during gait.

When this doesn't happen (forcefully enough) the abductor hallucis could be compensating for this?

It's easy to test the strength of the peroneus longus. And you could also check for 4th and 5th ray mobility, and cuboid mobility because not enough ROM in those joints can hinder the peroneus from working properly

 

Some questions:
?? gait reveals a vertical calcaneal position however significant midfoot instability and MTJ collapse more so on the symptomatic side. Is this another way of saying late stance phase or just after heel off pronation of STJ and/ or internal leg rotation?


?? Abductor hallucis flexes as well as abducts the first ray ??
Do you mean entire ray or just toe.


Late stance phase pronation can be caused by moments from ground reaction force, or moments from muscular action. Often, with a laterally deviated STJ axis the peroneal muscles will create a large pronation moment around heel off and this will cause "instability". A valgus forefoot wedge can decrease the need for peroneal activation and can decrease medial forefoot load.

Eric

 

I would want to rule out entrapment of the medial plantar nerve at the level of the porta pedis caused by the hypertrophic abductor hallucis muscle. See if you can reproduce the pain by having the patient stand and turning his body in one direction to maximally pronate the symptomatic foot Then press deep within the Porta Pedis and see if you can elicit tenderness. Do same test but with foot in a supinated position to open up the space within the Porta Pedis.

Sounds like he has late midstance pronation which together with his hypertrophic abductor is causing compression within his Porta Pedis. I would expect him to have symptoms during work.
Perhaps the brisk walking is increasing the external pronation moment enough to cause symptoms.

You may want to consider ordering nerve conduction velocity tests as well.

Steven