How Current Orthotic Thinking Influences Orthotic Prescription
Which paradigms, teachings and studies influence podiatric physicians who prescribe orthotics? These expert panelists enumerate what factors come into play when they dispense orthoses.
Which of the more current paradigms for foot function have the most influence in your practice?
“Time devoted to evaluating a patient in regard to his or her function as well as the biomechanical problem prior to prescribing the orthotic device will result in greater success with the completed orthotic device,” advises Ronald Valmassy, DPM.
In the same vein, Ray Fritz, DPM, is among the many DPMs who have been influenced by the Root theory and The Biomechanics of the Foot and Ankle, a text he says was his “bible for biomechanics” in podiatry school in the 1980s.
“I think much of this dogma still influences my thinking at times but I have drifted to a more simplistic approach to my orthotic prescription,” adds Dr. Fritz.
Presently, Dr. Fritz is giving more consideration to supporting the medial column and the arch of the foot, pointing out that midfoot function and control affect the rest of the foot. He is no longer exclusively concerned about function but concentrates on the contour, shape and specific individual characteristics of each foot. The individual deficiency or disease process also affects foot function, according to Dr. Fritz.
Lawrence Huppin, DPM, says he evaluates the literature and follows an evidence-based approach to orthotic therapy. He also voices suspicion about emerging “paradigms” for orthotic therapy.
“I’m disturbed by the proliferation of new ‘orthotic paradigms’ that have been propagated by several orthotic labs,” asserts Dr. Huppin. “From my perspective, these new paradigms are simply a marketing ploy designed to increase sales at a particular lab.”
Dr. Huppin elaborates that as one accepts a particular “paradigm,” he or she is required to use the lab that is promoting that new paradigm. Anytime a new treatment of any sort requires the physician to use a particular commercial entity in order to use that treatment, he says this is an indication that the treatment is “more of a sales tool than a legitimate new therapy.” By following an evidence-based approach to orthotic therapy, Dr. Huppin notes one could use any of at least a dozen high quality orthotic labs.
What factors influence your orthotic prescription?
Several studies have influenced Dr. Huppin’s method of prescribing orthoses. He cites a 1999 study by Kogler and colleagues, who demonstrated that valgus forefoot wedging decreases plantar fascial strain while varus forefoot wedging increases strain.1 Based on that study, he is “much more aggressive” in ensuring that the orthotic shell incorporates full valgus correction and will often incorporate a valgus forefoot extension in cases of plantar fasciitis.
Dr. Huppin says another example of incorporating evidence-based medicine into orthotic therapy involves prescribing orthoses for metatarsalgia. In 2000, Chalmers and Busby demonstrated that in patients with rheumatoid arthritis and metatarsalgia, semi-rigid orthoses are a much more effective treatment than soft orthoses.2 Dr. Huppin also cites a study showing that a total contact insert with a metatarsal pad was the most effective way to offload a metatarsal head.3 A 2003 study stated that one should place the highest point of a metatarsal pad between 6 mm and 10 mm behind the point of maximum pressure on the metatarsal head.4
Using this information, his preferred prescription for metatarsalgia is to use a semi-rigid polypropylene orthosis with a minimum cast fill. Dr. Huppin confirms that the orthosis conforms tightly to the arch of the foot. He also uses a wide orthotic plate, a cushioned topcover that he leaves unglued on the front half of the orthosis and a metatarsal pad. He suggests adjusting the metatarsal pad in the office so the highest point sits about 8 mm behind the painful metatarsal head.