Key Pointers On Increasing Orthotic Arch Height

I had a colleague call asking if there was any way to increase arch height on an orthosis. There are a couple of options but first, let us discuss arch height for a moment. A number of studies indicate that orthoses that conform closely to the arch of the foot are likely to be more effective at treating many of the most common complaints (including plantar fasciitis, metatarsalgia and hallux limitus) that we treat with foot orthoses.^1-3

In order for an orthosis to conform close to the arch of the foot, several things must happen in the casting, prescribing and manufacturing of the orthosis.

• Cast with the first ray plantarflexed.

• Prescribe a minimum cast fill with 2 or 3 degrees of inversion.

• Use an orthotic lab that does not overfill the medial arch.

When the above occurs and you receive the orthosis back from the lab, the device should conform close to the arch of the foot when the foot is in neutral position with the first ray plantarflexed. You can see this in the picture above at left. Compare that to the gapping that you see in the picture below on the right.

Now, back to my colleague’s question: what if the orthosis doesn’t conform close enough to the arch? By the way, in this situation, the orthosis is gapping from the arch because the doctor prescribed a standard fill orthosis with no inversion.

Here are two methods to increase arch height.

• Add a varus wedge to the orthosis. Adding a varus wedge to the heel post will invert the orthosis and act to increase the relative height of the orthotic arch.

• Add an arch pad under the topcover.

References

1. Kogler GF, Solomonidis SE, Paul JP. Biomechanics of longitudinal arch support mechanisms in foot orthoses and their effect on plantar aponeurosis strain. Clin Biomech. 1996; 11(5):243-252.

2. Mueller MJ, Lott DJ, Hastings M. Efficacy and mechanism of orthotic devices to unload metatarsal heads in people with diabetes and a history of plantar ulcers. Phys Ther. 2006; 86(6):833-42.

3. Roukis TS, Scherer PR, Anderson CF. Position of the first ray and motion of the first metatarsophalangeal joint. J Am Podiatr Med Assoc. 1996; 86(11):538-46.

Editor’s note: This blog was first published at https://prolaborthotics.com/Blog/tabid/90/EntryID/314/Default.aspx and has been adapted with permission from Lawrence Huppin, DPM, and ProLab Orthotics. For more information, visit www.prolaborthotics.com .