Current Insights On Custom And Prefabricated Foot Orthoses
Over-the-counter orthoses “have a place,” says Dr. Volpe. He says they can be helpful as trial devices to see if the patient will benefit from mechanical support or control. However, Dr. Volpe notes that a failed effort with an OTC device “surely does not always mean that a custom device, with all of its inherent benefits, will not benefit the patient.” He prefers using a weight-dispersive strapping as a trial or temporary therapy to ascertain whether repositioning the foot will help reduce symptoms. For patients who need soft tissue supplementation or accommodation, he notes that a well-cushioned OTC device can be a good first line of treatment.
Dr. Spencer notes that OTC orthotics are not useful for all patients but patients can greatly benefit from them if they need some control of foot function or may have financial restrictions that prevent them from utilizing prescription orthoses. In the same vein, Dr. Volpe reserves OTC devices as an option for patients when custom devices are cost-prohibitive. He notes that many orthotic labs have “semi-custom” lines that match a cast to a line of prefabricated shells that one can customize somewhat.
“These devices are a nice compromise between OTC and fully custom devices, and serve as a nice bridge in lowering the cost while still providing the patient with a quality device,” says Dr. Volpe. “In addition, the quality of OTC devices offered by some labs has also improved dramatically so they are able to function as controlling devices when indicated.”
Q: In your opinion, what would make a good OTC foot orthotic device?
A: Using a thermoplastic shell as a basis for design is the key for a quality OTC device, according to Dr. Spencer. He recalls seeing less than optimal results with OTC inserts that provide poor motion control to the foot.
“Regrettably, I think many patients who use OTC inserts do so before speaking with a podiatrist and end up with something that does not help them,” notes Dr. Spencer.
If one desires motion control, Dr. Volpe says the material must be moderately non-conforming, maintaining its shape and offering support under loads. Further, he notes that an adequate height to the arch is beneficial and the plantar surface of the device should not rock when one places it in the shoe. In a generic device, Dr. Volpe notes the advantage of a soft tissue supplement at the foot-orthotic interface for comfort.
In cases in which shock absorption or accommodation is the issue, Dr. Volpe prefers to use a laminated device with materials of different densities that work together to optimize outcomes. He prefers having a lower durometer or a more accommodating material closer to the foot-orthotic interface. Dr. Volpe adds that one may layer a higher durometer material beneath it to add some body or support to the device. The top cover should be appropriate for the patient’s activity, according to Dr. Volpe. He suggests nylene or Spenco materials as useful in reducing friction while vinyl is helpful if orthoses have to be cleaned frequently.
“I would also add that one has to be careful sometimes that an OTC device does not distract a patient from the potential benefits of moving on to a custom device over time. If one uses only symptoms to gauge results with an orthosis, a given patient may have a relief of symptoms with an OTC device that may prove to be temporary,” maintains Dr. Volpe.
In some cases, Dr. Volpe says moving the patient to custom-level therapy may be the difference between short-term and long-term benefits. He adds that a superior custom device may also help prevent other compensations and maintain neutral position function of the foot, which may have other lasting benefits for the musculoskeletal position over time.
As Dr. Kimmel advises, there must be some level of customization, whether the device is heat moldable to the patient’s foot or there is the ability to add some degree of posting. If an OTC device were sold with pads so the patient could add an accommodation or post, he feels that would help significantly.