I recently spoke with a doctor who noted on one of his prescription forms that he wanted an orthosis to “control servere pes planus” and yet prescribed a “narrow” orthosis. By definition, a narrow device is one that is ground lateral to the first met bisection.
A narrow orthosis has less area against the foot available to apply a supinatory torque medial to the axis of the subtalar joint. Thus, a narrow device is contraindicated in situations where you require control over a very pronated foot (one with a medially deviated subtalar joint axis).
On speaking to the doctor, he stated that he had prescribed a narrow orthosis because the patient had a narrow foot.
You can find more detail on orthoses for pes planus elsewhere on the website – just use the search feature. The point of this blog é is to remind everyone that when prescribing orthotic width, remember that the width is RELATIVE TO THE FOOT.
Here is a good way to think about orthotic width:
- Normal width: Bisects 1st metatarsal shaft
- Narrow width: To lateral aspect of 1st metatarsal shaft
- Wide width: To medial aspect of 1st metatarsal shaft
- Medial Flange: Wraps medially around the medial arch.
So, the width of the foot does not matter. If you need more control, order a wider orthosis. A wide orthosis will not be wider than the foot, regardless of the width of the foot.
ProLab takes a scientific approach with our orthoses by integrating evidence-based medicine into orthotic therapy. Our team of Medical Consultants regularly evaluates the medical literature pertaining to orthotic therapy and biomechanics. ProLab clients are encouraged to contact a medical consultant whenever they have questions about an orthotic prescription.
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