Inside Insights On Evidence-Based Orthotic Therapy
Given the increased emphasis on evidence-based medicine, our expert panelists review the impact of literature findings upon their prescription of custom foot orthoses for different pathologies.
Q: Is there evidence in the literature to support the use of functional orthotic devices?
A: The only supporting evidence relative to orthotic treatment of posterior tibial tendon dysfunction (PTTD) are studies of ankle foot orthoses (AFOs), according to Doug Richie Jr., DPM. Regarding PTTD, he says the evidence is “quite impressive” as it reveals that over 50 percent of patients can obtain satisfactory relief of pain and can avoid surgery. These studies cited by Dr. Richie primarily utilize solid AFOs with leather gauntlet restraint closures.
Regarding functional foot orthoses, Dr. Richie says reports in the literature are anecdotal when it comes to rates of success and outcomes of treatment. He notes that overall, the success and specific prescription criteria for orthotic therapy for PTTD “remain open for debate.” Orthopedic literature usually recommends using a University of California Biomechanics Laboratory (UCBL)-type device as the typical orthotic intervention before surgery, says Dr. Richie. He adds that he is not aware of any studies of patients with PTTD using a podiatric functional foot orthosis.
Many labs offer a “PTTD” device that incorporates a deep heel cup, medial and lateral flanges, and a medial heel skive of 4 mm to 6 mm, according to Dr. Richie. Additionally, he notes some labs recommend a “sweet spot” to accommodate a subluxing talonavicular joint.
“These all appear to be valid foot orthosis prescription criteria to control the severe collapsing pes valgus foot,” notes Dr. Richie.
Since PTTD is primarily a transverse plane deformity, Dr. Richie notes a foot orthosis “has little ability to control the foot in this direction.” As he has discovered, transverse plane-internal rotation of the tibia in this pathology drives the talus into severe adduction and an AFO has better leverage to control tibial rotation than a foot orthosis.
“Evidence-based medicine will be the basis for how we treat our patients in the future,” says Larry Huppin, DPM. Given that, he notes significant evidence in the medical literature on using orthotic interventions to treat various pathologies. Dr. Huppin adds that most podiatrists will find they are not currently using the best available evidence in writing orthotic prescriptions. However, he notes there are evidence-based prescription recommendations for conditions including plantar fasciitis, hallux limitus, adult-acquired flatfoot, tibial fasciitis, patellofemoral dysfunction, metatarsalgia, tarsal tunnel syndrome, lateral ankle instability, peroneal tendonitis, posterior tibial tendonitis and sesamoiditis.
Dr. Huppin says in the Department of Applied Biomechanics at the California School of Podiatric Medicine, all the instruction in orthosis prescription writing is based on what the literature indicates is the most effective orthotic prescription for the given pathology.
“Using this pathology-specific orthosis approach to orthotic prescription writing would help most podiatrists improve their clinical outcomes and I would encourage all podiatrists who use orthoses in their practice to ensure they are aware of evidence-based orthotic prescription writing,” says Dr. Huppin. He recommends attendance at the International Conference on Foot Orthotic Therapy and Biomechanics, which is held every December.
Clinical and non-clinical biomechanics studies, conducted in a variety of disciplines, continue to produce results supporting the use of orthotics for many different foot and ankle problems, according to Cherri Choate, DPM. In evaluating these studies, she says one can appreciate the significantly different approaches to orthotic usage and definition.
“I have recently recognized the importance of each of these disciplines and their resultant conclusions as each piece helps us build a more clear evidence-based foundation for orthotic therapy,” says Dr. Choate.
Q: What recent literature has influenced how you write orthotic prescriptions?