Key Insights On Orthotic Fabrication And Replacement

Author(s): 
Guest Clinical Editor: David Levine, DPM, CPed

These expert panelists expound on replacing orthoses, determining which type of orthoses to fabricate and what types of shoes patients should wear with orthoses.

Q:

How can you tell when it is time to replace orthotic devices and do you rely on objective or subjective measures?

A:

David Levine, DPM, CPed, notes the question of replacement frequently arises even when a patient presents for a non-orthotic related visit. If the patient is not experiencing any new symptoms or having any problems with the existing devices, he sees no need to replace them. He and the other panelists note that if the symptoms are increasing in type, frequency or severity, that might be an indication that it is time to fabricate new devices.

   However, when a more detailed examination is necessary, Dr. Levine advises considering certain factors, one of which is how well the devices conform to each foot. For functional types of devices, with the foot in subtalar neutral, Dr. Levine says the orthotic should fit the contour of the foot intimately with no gapping between the orthotic device and the foot. However, he does note this is not objective criteria.

   Dr. Levine says another factor for replacement is how well the orthotic conforms to the positive cast as this helps determine whether a change in the shape of the material has occurred. He notes that with softer accommodative material, wear is more visible. In many cases, Dr. Levine says it may be more cost-effective for patients to refurbish existing devices. He notes that DPMs tell patients that orthotic devices typically last from three to five years but during that time, material can wear and feet can change.

   One should replace orthotic devices if there has been a change in foot morphology, material deformation or an inability of the current devices to maintain optimum alignment or function, according to Joseph D’Amico, DPM. He says improvements in arch morphology are common with the continued use of prescription foot orthoses. Dr. D’Amico adds that one can confirm this by placing the device against the foot in a non-weightbearing subtalar joint neutral position and noting whether the device contours to the foot as well as it did when one first dispensed the device. If there is a gap on the medial border, Dr. D’Amico says upon weightbearing, the foot will have to collapse down to the orthotic before it can begin to function. This may occur anywhere from six months to two years after initial dispensing, according to Dr. D’Amico. He says one should also examine patients while they are weightbearing in the neutral position in the devices.

   When it comes to replacing orthotics, Lee Firestone, DPM, generally recommends replacing orthotics if they are greater than seven to 10 years old. However, he notes this timeframe changes if the integrity of the shell is compromised or if there has been significant structural change to the patient’s foot from trauma, surgery and even pregnancy. Dr. Firestone will not hesitate to replace the orthotic if the patient complains that the orthotics are no longer supportive. In addition, he will recondition an old orthotic for up to 10 years as long as the patient is happy with the orthotics and he or she remains asymptomatic.

   “The bottom line is that there is a range of time that orthotic devices will last,” says Dr. Levine. “It is not as if they go bad all of a sudden so it may be worthwhile to modify, refurbish and work with existing devices prior to remaking unless they are beyond repair.”

   In general, Dr. D’Amico says one should biomechanically reassess the individual every two years to see if the original device prescription agrees with the current examination findings. If there is still doubt as to whether the orthoses are functioning satisfactorily, he notes a computer assisted gait analysis may document the effectiveness of the devices.

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