A Closer Look At Orthotic Technologies And Modifications

Guest Clinical Editor: Lawrence Huppin, DPM
   Q: What materials and equipment do you keep in the office for orthotic modifications?    A: In his office, Dr. Kirby uses 1/8- and 1/4-inch of adhesive felt, 1/4-inch of Korex and neoprene insole material for foot orthosis modifications. Drs. Kirby and Volpe use grinders, barge cement and several sizes of metatarsal pads. In addition, Dr. Volpe keeps a heat gun, some top covers and soft tissue supplements, basic add-ons and metatarsal pads in his office.    Dr. Huppin uses 1/8-inch of soft ethylene vinyl acetate (EVA), a long-lasting cover material which he says is easy to work with, conforms to the deepest heel cups and cuts cleanly to provide a professional look to the orthosis. He also uses the FumeBuster fume filtration system (Purex), which he says vacuums fumes into a charcoal filter, eliminating barge odors.    Q: When writing an orthotic prescription, what are the most important concepts to consider to achieve the best clinical outcomes?    A: Dr. Huppin says the most important factor is the patient’s presenting pathology. First, one should determine the etiology of the pathology and base the orthotic prescription on those findings. For example, if the patient has plantar fasciitis, Dr. Huppin says the goal with functional orthotic therapy is decreasing tension in the plantar fascia. Plantar fascial tension increases when the foot lengthens, whether it is due to an everted heel or an everted forefoot, according to Dr. Huppin. If the plantar fasciitis appears to be caused by an everted heel, Dr. Huppin says he might use a deep heel cup and a medial skive. If it is due to an everted forefoot, he may prescribe a reverse Morton’s extension.    Likewise, Dr. Kirby emphasizes the importance of tailoring orthotics to individual foot types, taking into account differing structure and function.     “Far too many podiatrists are lazy in their orthosis prescribing habits. They basically order the same orthosis design for each patient, somehow expecting that the arch support they are creating for their patient will ‘magically’ have an effect on their patient’s foot so his or her symptoms will improve,” says Dr. Kirby.    Dr. Volpe initially performs a static biomechanical evaluation and follows this with a dynamic gait assessment. After making a diagnosis, he suggests DPMs should weigh the diagnosis, the existence of biomechanical and other comorbidities, consider what they want the orthotic to accomplish, and then write a prescription that will best meet that patient’s goals. Dr. Volpe emphasizes considering the patient’s shoe gear as well.    Q: What is the role of computerized foot pressure analysis systems in prescribing foot orthoses?    A: Dr. Huppin cautions DPMs to take a critical look at pressure analysis products and carefully evaluate the claims of the companies that sell them. He says pressure analysis can play a vital role in prescribing orthotics. Systems like the F-Scan (Tekscan) provide information on pressure distribution and force/time curves that can help an experienced practitioner write orthotic prescriptions and adjust orthoses, according to Dr. Huppin.    Dr. Kirby cites the best pressure analysis devices as the F-Scan, RSscan (RSscan) and Emed (Novel) systems. He says each system has advantages and disadvantages as far as sensor accuracy, software for computer analysis, ease of setup and price. Although he does not use those particular systems, he has followed technological advances in the pressure analysis area and believes those devices improve every year. Dr. Kirby says those who use such products can utilize the devices’ objective data to enhance their outcomes with orthotics.    Dr. Volpe concurs. He notes a computerized pressure and gait analysis can provide objective information about pathological structure and function, and also clarify the goal in prescribing a particular patient’s orthosis. Computerized systems offer another advantage since they permit the testing of patients after prescribing therapy to determine if the desired changes or goals are really occurring, notes Dr. Volpe. Otherwise, practitioners tend to depend on the subjective reduction of symptoms to determine the efficacy of therapy.     “While this is perhaps the first and foremost goal in this era of outcomes medicine, it is valuable to be able to document objectively that desired changes are occurring,” comments Dr. Volpe.

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