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I have a patient with mid to distal 5th MT pain. She brought with her orthotics prescribed 5 years ago for plantar fasciitis. Three months earlier developed 5th MT pain and recently broke the orthotic shell. I'm struggling with her mechanics.

At first glance I see a plantarflexed 1st Ray;valgus forefoot, but when thats taken out of the equation, the lateral forefoot looks varus. She has little STJ eversion motion (less on the affected side). Could her inability to fully compensate at the STJ for a rigid forefoot varus component have caused a plantarflexed first ray? If thats the case...any thoughts on orthotic posting.

Thanks

C. Tull, DPM

 

How much "lateral arch" does the old device have? what is it made of? and to what extent is/are the lesser rays dorsiflexed or plantarflexed in neutral weight bearing and in late stance/propulsion?.....does she have any available range of motion in the sagital plane through the mid foot?

 

Old device looks like subortholen (made by orthotist). Can't answer about the "lateral arch". Lesser mets have about 4 degrees plantarflexion and very little dorsiflexion capability. When attempts made to dorsiflex the lesser mets the entire rearfoot moved (everted slightly) then limited any further dorsiflexion. Rearfoot was slightly everted through mid stance and propulsion. Limited answers to your questions...sorry. Do lesser mets plantarflexed through mid-stance/propulsion? Don't know how to assess this.

 

Obviously my input has limited relevance...but it sounds like you've got a really rigid foot type with altered joint axes and less than typical ranges of motion in sagital plane.
What chance of some mobilization of all these midfoot articulations to see which way they can move....when and if they can move?
I have sometimes used a large-ish lateral column/cuboid support under this kind of foot to try and mobilize a little more range and dynamic function...which should help get absorption of plantar forces to be a little more dynamic/better. You are surfing a line of intolerance as the flip side of course....not a fast process.
Good luck
Phill

 

I like Phill's response--try to mobilize the midtarsal joints to see how much range of motion is actually available. If the joints don't respond to mobilization therapy then you could try an EVA forefoot extension that has an excavation below the 1st MPJ and a varus grind under the 2nd through 5th MPJ's. While I am not a fan of extrinsic forefoot varus posting (as it tends to increase tension on the medial slip of the plantar fascia) I have had success using this type of extension in a foot that is not responding to joint mobilizations. Hope that helps.

Bob

 

Thanks for the input......

 

Could it be lateral column overload from a rearfoot varus. Additionally, any forefoot valgus correction in the device will increase lateral forefoot load. Another way to look at it, the device may be trying to evert the foot farther than it can go in terms of range of motion of the MTJ and STJ. I usually have patients stand and attempt to evert their feet. Some people have range of motion to do this others do not. It is important to look at when you design the orhtotic. An intrinsic forefoot valgus post will curve away from the distal 5th met shaft when the orthosis is held against the foot in the casting position. This curvature lifts the middle of the shaft higher off of the ground when the patient is standing on it. This can be the cause of 5th met overload, if the patient does not have range of motion available.

Eric

 

And yet I believe there is plantar force measuring evidence to suggest that with some feet a lateral forefoot wedge will actually help the medial side of the foot load up better.
Regards Phill