Orthoses and cold toes

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Dear all

Do you think or have you ever had the situation that the pressure applied to the plantar medial arch by the orthosis was sufficient to occlude the plantar arteries?

I have a male customer a fit 66 year old who had a severly painful metatarsalgia which was a combination of plantar interdigital neuritis and 2nd MPJ capsulitis. I made a full contact EVA device with met bar and 2nd MPJ cut out. The result was total resolution of pain for which the customer was very pleased and he feels that the orthoses are very comfortable. However he did note that when he wore the orthosis his toes became very cold. The shoes were loose enough and did not appear tight on the dorsal aspect. Evaluation of the circulation status seemed fine and no other medical history admitted.

Never had this complication with orthoses before, Any ideas?

Dave

 

Do the toes actually become cold or does he just perceive them as feeling cold?

 

Good question, don't know but his toes didn't feel particularly cold on examination but then if it were vascular occlusion they may not take long to warm up once the shoes are off. So short of somehow measuring the skin temperature inshoe it might be difficult to determine.

Cheers Dave

 

I have no idea if this is the reason and I taking a stab in the dark and do not even know if such a thing is even possible --- but what about something autonomic following resolution of the neuro problems???? ....

 

Ok I'm listening, How would that work and what could do about it? Are you talking some imbalance between para and sympathetic system due to removal of intense pain stimuli? Walk me through your thoughts!


Dave

 

Dave:

I have seen this once before. It could be possible that your "met bar" is occluding one or a few of the plantar arteries and/or compressing the plantar nerves. I would suggest removing or reducing the thickness of the met bar to see if this resolves the feeling of "cold toes" to troubleshoot this relatively infrequent orthosis problem.

If removing the "met bar" resolves the cold toes, but increases the metatarsal head pain, then it is just a matter of mechanically redistributing the orthosis reaction forces proximal to the metatarsal heads in such a fashion that the higher pressure areas are eliminated. I have often solved this type of problem by the addition of a slight (3 mm) heel lift or neoprene/EVA/korex under the rearfoot post of the orthosis.

Often times, if there is an equinus deformity, or if the patient is in a shoe with a low heel height differential, the addition of a slight heel lift under the orthosis will reduce the anterior edge pressure from the orthosis by decreasing the tension force within the Achilles tendon. Also, be aware of the heel height differential of the shoe and the durometer/thickness of the forefoot portion of the midsole of the shoe since this may also significantly affect the ground reaction forces plantar to the metatarsal heads.

Please let us know how this works.:drinks

 

Kevin

Yeah, that makes sense, the met bar thickness causes an extra dosiflexion moment about the ankle and so increases GRF plantar to the distal mets.
He's back for review in a couple of weeks so I'll let you know.

Dave

 

By the way, Dave, Happy Easter!!:drinks

 

If there is sufficient change to GRF/ORF to modify neural pressure mechanically, then there is likely sufficient (force) to modify extra-vascular pressure at the plantar met / perforating arteries...

I have observed this cause-effect several times this year with met dome/bar application & modification during PPT / Neuroma / Bursitis Mx.

Physically cold digits ; particularly 2nd/3rd. Not painful, just noticed.
Modify/increase pitch @ HO and reduce dome thickness and/or location dome ant border has achieved significant improvement.

Maybe the assumption of proximal dome pressure providing a mechanical benefit to met heads has a common, albeit lesser symptom of partial plantar vascular occlusion in some anatomies. On that note, how much continuing digital discomfort in FF 'pathology' cases may be directly associated with vascular I wonder? :morning:

How about Raynaud's-type predispositions/cases... any significant direct mechanical contribution? Has anyone tried managing Raynauds symptoms with change to GRF's at the FF?