Previously, I discussed the fact that several large podiatric labs commonly provide an orthotic fabricated over a prefabricated mold and sell this device to a doctor under the guise of a “custom foot orthoses.”
The solution would be a request from the doctor for the original positive cast from the lab. The original positive cast would show the cast corrections and one could also measure this against the patient’s foot. However, many labs will not provide a return of positive casts. Furthermore, most podiatric physicians are surprised to see that the positive models are carved from automated routers on wood or wax molds, using digital technology.
Yes, the days of hand-corrected plaster models to fabricate custom functional foot orthoses are nearly over. The dramatic shift to automated technology -- using digital scanning of negative casts, computerized “correction” of the negative cast image and fabrication of a corrected positive model using high tech milling machines -- has enabled podiatric laboratories to become more efficient and possibly more accurate in their production of quality custom foot orthoses.
Certainly, digital imaging of cast corrections and utilization of sophisticated computer programs have enabled laboratories to have better control over the subtle nuances of correction and balancing of positive casts for fabrication of foot orthoses. However, this technology can also give rise to short cuts by some unethical labs that pre-program their corrections to match a “library” of positive molds manufactured ahead of time to produce a partially prefabricated device.
You should check with your lab to make sure that you understand its cast correction technique and are comfortable that the lab is performing the modifications according to your specifications. If your lab is using a library system, you should be entitled to a significant price discount in comparison to the cost of true custom orthotic devices.
The vast majority of laboratories manufacturing custom foot orthoses do not take short cuts and consistently provide true custom devices for the practitioner. In fact, the few major labs I know of who have been cheating doctors by substituting a prefabricated orthotic for a custom order do not even manufacture a positive cast model for fabrication of the orthotic. It is entirely appropriate to occasionally check on your lab by requesting a return of the positive model along with the custom orthoses to check for fit and quality. Better yet, I would suggest visiting your lab and inspecting the lab’s cast evaluation and correction techniques. Make sure the device you are ordering is the same as what you would make yourself if you had the time.
Next month: How much do you charge for custom foot orthotics?