Enlarged 5th met/cuneiform

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Dear All,

I have seen many patients who have an enlarged 5th met/cuneiform . On the brother and sister (11 and 13 years) pair I am treating presently, they both have significant lower extremity discomfort, medial long arch strain, anterior knee pain, and plantar heel pain. They are active in a variety of sports, can play with pain which is never disabling but pain is a constant presence during and after sports. They have normal ROM, even at the true ankle joint which I would have expected to be tight. There is significant eversion of the calcaneous( Valgus) and medial long arch flattening on both these kids.

The question I have is this: is there a direct relationship between a prominent 5th met/cuneiform and a form of functional equinus? I seem to do better in controlling these types of feet,and reducing their sympstoms (adult or pediatric) when I put in between a 3 and 5mm heel raise. I believe the heel raise serves to reduce the 'pivoting' abductory stress on the 5th met/cuneiform.

Sincerely,
Freeman

 

Freeman:

The 5th metatarsal is two metatarsals away from the most lateral cuneiform. Where exactly on the foot, then, are you referring to??

 

Kevin

Despite this anatomical error...I suspect Freeman is pointing out an prominent styloid process in conjunction with a met adductus +/- midfoot breach/rockerbottom foot exacerbated by posterior calf equinus. The 5th MT-cuboid articulation can ? never be prominent per se as it is masked laterally by the 5th MT tuberosity. Unless there is SEVERE osteophytic growth around the articulation, which I don't think I have ever observed becoming a surface landmark.

In the words of an Australian cultural (sic) ambassador; "Please explain?"

 

Cuboid, cuboid, forgive me, I meant cuboid!!! (I feel like I have been severly admonished, over the internet!...and rightly so) I revert back to many years ago when I considered the cuboid a cuneiform for both the the 4th and 5th because they didn't really have ones of their own.

Yes it is a prominent styloid process and on examining the slipper casts, they do have a bit of a rocker bottom at the styloid process. I do appreciate that the cuboid would not weightbear unless there is significant articular destruction and such is not the case .

My question is :why (mechanically) are these prominent? Also, may I post a photo on this forum for better explanation?

Wait till I ask about plasterflexed metamucil heads!
I am so embarrassed.
Freeman

 

Freeman,

No need to be embarrassed, we all make mistakes.

The styloid process of the 5th metatarsal will tend to be more prominent in feet that have a high degree of metatarsus adductus deformity. This is due to the convex lateral border that will occur in these feet due to the metatarsus adductus deformity and increased adduction angulation of the 5th metatarsal which makes the styloid process of the 5th metatarsal more prominent in these feet.

When a metatarsus adductus deformity occurs in association with a pronated rearfoot, this is commonly called a "skewfoot" or "Z-foot" deformity" since the calcaneus is more abducted away from the talus (which is relatively adducted) and the forefoot is adducted. I suspect that this is the type of foot that your patients have. You may attach photos via the "additional options" section and "manage attachments" option below the "reply to thread" section of the Podiatry Arena posting area (i.e. just below the area where I am writing this posting to you).

Most feet with flatter than normal medial arch height that also have pronation-related symptoms will respond favorably to a heel lift since the increased sagittal plane declination of the plantar foot will theoretically reduce the medial arch flattening moment (i.e. reduce the rearfoot plantarflexion moment and forefoot dorsiflexion moment) by reducing the tensile force in the Achilles tendon during the latter half of stance phase of gait. I have discussed this concept today already in my posting on Achilles tendon and plantar fascial tension. http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=1445

I don't know of any biomechanical relationship between a "functional equinus" and a prominent styloid process of the 5th metatarsal otherwise.

Hope this helps.

 

Thank you Kevin!

Whereas neither of ther 2 patients have any restriction in the true ankle dorsiflexion, but exhibit these enlarged styloids, and seemed to do well with a 3-5 mm heel raise, I call them functional equinus (right or wrong) Their overall posture, is very good so I do not have reason to suspect their pelvis is out of whack causing posterior shortening.

Thanlks you for your detailed explanation.

Sincerely
Freeman