I had a ProLab client call complaining that he had a patient that was feeling that their orthotic device is too hard. He wanted to know if he could possibly make a softer orthotic for this patient. It should be noted that the patient weighs 310 pounds.
Patients who are obese are, of course, putting significant pressure onto their feet and when wearing orthosis there is significant force between the orthosis and the foot. Much more so than on an average weight patient. This means that these patients have more potential to feel the arch of the orthosis as being too high or too hard.
Unfortunately if you make a softer orthosis for such a patient, the devices likely to collapse under the foot very quickly and not provide adequate support to relieve the patient’s symptoms.
A better idea is simply to make a wider orthosis. A wider orthosis will spread force across the larger surface area, so the patient is much less likely to feel the device as being too hard or too high.
For obese patients, I recommend using at least a wide orthosis and in many cases using a medial flange. A wide device will extend to the medial aspect of the foot and a medial flange will wrap around the medial arch. Both of these will help redistribute force better than a standard width orthosis and are almost always more comfortable for these patients.
Also, these wider devices allow you to use a more rigid orthosis that is likely to provide the patient adequate support.