Pertinent Roundtable Insights On Indications For Orthotic Management

Guest Clinical Editor: Ronald Valmassy, DPM

A: For Dr. Burns, posterior tibial tendon dysfunction (PTTD) is the most challenging condition to treat as it is a loss of the primary decelerator of pronation that typically occurs in a badly pronated foot. He says the condition almost always requires foot and leg support. Dr. Burns adds that acute cases require immobilization. In some instances of PTTD, he says a lace ankle brace over a custom orthosis may be helpful during rehabilitation. Then the patient can use the laced ankle brace for increased demand as recovery continues, according to Dr. Burns. He notes that a Richie Brace can be helpful for these patients.
Tarsal tunnel syndrome is the most challenging condition to treat with orthotic devices, according to Dr. Blake, who says the plantar nerve sensitivity makes arch support very painful. In these cases, he notes the foot that needs good support to prevent heel valgus cannot tolerate that support. Dr. Blake cites tape as a good option for many of these patients since even soft orthotics can be intolerable.
Dr. Kirby says dorsiflexion stress injuries to the lateral midfoot are challenging. He calls these injuries lateral dorsal midfoot interosseous compression syndrome (lateral DMICS) wherein the dorsal aspects of the lateral midfoot joints, such as the fourth and fifth metatarsal-cuboid joints, are painful with ambulation. The cause of these injuries is an excessive dorsiflexion moment on the lateral column joints. Dr. Kirby says this is caused by either an over-supinated foot or a foot that is at the end range of pronation of the subtalar joint. Yet there is still increased ground reaction force on the lateral metatarsals, according to Dr. Kirby.
He says these injuries are much harder to treat with orthoses since most orthosis designs tend to supinate and not pronate the foot. Dr. Kirby notes that orthotic modifications for lateral DMICS include a lateral heel skive, an everted balancing position, increased medial expansion plaster and valgus forefoot extensions. With these modifications, Dr. Kirby says one can try and evert the rearfoot, and reduce the dorsiflexion moments on the lateral column during weightbearing activities.
Another challenging case for Dr. Burns is central metatarsal overload without specific plantar plate insufficiency. In these cases, it may be difficult to pinpoint the etiology of the pain so the treatment may be less targeted. He notes the importance of exactly fitting the orthotic shell to the plantar aspect of the forefoot.
Dr. Burns adds that he often has the shell molded directly to the positive cast with only some expansion for the heel cup. Then he uses extrinsic forefoot posts, if necessary, for balancing.
An accommodating forefoot extension like Plastizote can permit dynamic molding of the extension to the forefoot, according to Dr. Burns. He says this provides some cresting and support of the toes, and helps to further reduce pressure under the metatarsophalangeal joints (MPJs). In such situations, Dr. Burns prefers using Spenco type topcovers to reduce the shear forces. He notes that a heel raise may help accommodate for equinus, either in the ankle or forefoot.

Q: What is the role of the functional foot orthosis in the management of bunion deformities?

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