These experienced panelists discuss the unique challenges of fabricating orthotics and creating modifications for various types of sports, high heels and Morton’s neuroma.
In regard to sports activities, Ronald Valmassy, DPM, finds that the standard three-quarter length orthotic device, whether it is polypropylene or graphite, typically works quite well with a sports shoe. Dr. Valmassy says the patient also has the flexibility to utilize that same orthotic device in a variety of other shoes.
However, if he chooses to prescribe an orthotic device that patients would utilize only in a specific pair of shoes, such as running shoes, basketball or tennis shoes, Dr. Valmassy typically will ask for a full-length device. He notes the full-length device will still incorporate the same inherent and intrinsic varus or valgus correction with the medial or lateral calcaneal skive. Dr. Valmassy will also ask the lab to add a soft, shock absorbing material to the arch area and throughout the topcover material.
“Clearly, having a full-length orthotic device for sports-related activities allows the device to stay better seated in the shoe without having the patient experience the common complaints of the orthotic device slipping excessively. Additionally, a flat rearfoot post will assist in decreasing lateral instability,” says Dr. Valmassy.
Joseph D’Amico, DPM, prescribes unique sport devices for water sports such as paddleboarding, windsurfing and aqua aerobics. As he notes, the module he uses for all water sport orthoses is ethyl vinyl acetate (EVA) to the sulcus with an AliPlast topcover (AliMed) to the toes with rearfoot posting and forefoot posts extended to the sulcus. When he receives the orthotics, Dr. D’Amico makes a series of 1/8-inch drill holes through the entire shell to allow for water drainage.
“These lightweight, floatable devices not only fit into most aqua footwear but work exceptionally well at improving alignment, function and performance,” notes Dr. D’Amico.
Bicycling is one sport that requires special orthotic consideration, according to Stanley Beekman, DPM. He will make full-length rigid orthoses and add a metatarsal pad and toe crests. Dr. Beekman says the full-length rigid orthosis aids the propulsive phase of the pedal stroke whereas the metatarsal pad and toe crest aid the bottom half of the cycle when the foot is pulling back. As he notes, this allows the foot to pull against the orthosis more effectively. The force then transfers to the plantar portion of the counter, which is more rigid than the superior portion. From the counter, the force transmits to the sole and then the pedal, according to Dr. Beekman.
When fitting orthoses to women’s pumps, Dr. Beekman cites several important keys. First, he says one must make as much room as possible by removing the sock liner and making the orthoses as thin as possible in the areas that contact the shoe. Second, get the orthoses to fit the shape of the shank by casting with the feet in a dangling position and using a flexible material. Third, keep the heel in the shoe by keeping the calcaneus as posterior in the shoe as possible, which one can do by lowering the height of the heel cup. When grinding a heel cup to a lower height, Dr. Beekman says podiatrists will see thickness around the heel cup. Reduce this thickness and the foot will be able to move posteriorly, according to Dr. Beekman.
Dr. Valmassy suggests considering vacuum casting techniques to better capture the unique characteristics of a specific high heeled shank. Other than that, he says utilizing a thin material, either polypropylene or graphite, is essential to this type of device. He says one should cut the device narrowly. In these cases, Dr. Valmassy typically asks for a very shallow heel cup, realizing that he is sacrificing some control. However, he warns that any heel cup depth beyond 2 to 4 mm will compromise the use of the orthotic device in most fashionable shoes. He typically asks for a Holethotic, which has a hole in the heel area to maximize contact of the patient’s foot with the inner sole of the shoe. As Dr. Valmassy explains, a Cobra or serpentine type of orthotic also tends to reduce the overall bulk of the orthotic device itself and leads to a better fit in most instances.
If there is a sagittal plane deficiency, forefoot deformities or symptomatology, Dr. D’Amico employs a device with a calcaneal inclination enhancement of 2 to 4 mm to prevent forefoot calcaneal migration and enhance sagittal plane control. With heel heights over 3 to 4 inches, he says an ultra-thin graphite composite shell with a heel cut-out, intrinsic rearfoot and appropriate forefoot posts is often effective.
Since women in a high heel shoe walk on an inclined plane, Justin Wernick, DPM, says the mechanical objective is to use a modification that levels the heel. That way, he says one can reduce that plantarflexory force on the forefoot. Dr. Wernick also notes that using a sagittal plane post on the heel of the orthoses is very helpful and suggests angling the post so the anterior edge is thicker than the posterior edge. There is no varus or valgus angle in his design.
Dr. Wernick also notes that casting the foot in the type of shoe to be worn will give a much more reliable impression of the foot as it functions in that shoe. The arch height will increase as the heel height increases so he says fabricating the shell with this built-in arch height helps the foot resist sliding forward. Additionally, Dr. Wernick notes that leveling the heel and filling the arch of the foot will reduce the load on the metatarsal heads.
For high heels, Dr. Valmassy feels the most important consideration is realizing that the correction of the orthotic device decreases significantly as the shoe becomes more stylized and the heel becomes higher.
“Certainly, there are a few considerations to make that will allow some degree of comfort and stability that clearly goes well beyond any type of over-the-counter support,” notes Dr. Valmassy.
Heel height and type are among the factors that dictate the prescription of foot orthoses for women’s fashion footwear, according to Dr. D’Amico. He employs intrinsic rearfoot posting in most fashion footwear not so much because of its reduced effectiveness in higher heel heights but because it stabilizes the rearfoot in the shoe itself. Dr. D’Amico cites the Slimthotic (Langer), a subortholene shell with a cutout central heel region and extrinsic rearfoot post, as an example.
Dr. D’Amico has found metatarsal pads, neuroma plugs and digital crests to be helpful modifications for Morton’s neuroma. In his experience, the metatarsal pad works well to rest on the longitudinal arch and spread the central metatarsal.
Dr. Beekman has found that using a metatarsal pad and a 1/8-inch Korex extension under the fifth metatarsal head is effective. He notes an additional adjunct is manipulation of the fourth metatarsocuboid joint.
Dr. Wernick finds most patients with neuroma have a ligamentous lax foot type in which there is a large range of motion in the joints of the foot, especially in the transverse plane of the midtarsal joint. He notes this results in a relative abduction of the forefoot relative to the rearfoot. In this situation, Dr. Wernick says there is more movement of the medial column of the foot than in the lateral column, resulting in shearing of the nerve, particularly between the third and fourth metatarsals.
As Dr. Wernick notes, the object in orthotic design is to control motion in the subtalar joint while stabilizing the lateral column with an arch both under the calcaneocuboid joint as well as the medial side. One can achieve this by modifying the positive impression with the removal of plaster under the calcaneocuboid joint area. Dr. Wernick cites the importance of resisting flattening of the lateral arch. He also notes that since most shoes, particularly women’s shoes, have a last that has the longest part of the shoe at the third toe, there is a lateral compression force.
In regard to orthotic modifications for a neuroma, Dr. Valmassy says in some cases the use of a forefoot extension that leads to the sulcus is helpful in providing some additional shock absorption and cushioning in the forefoot. He also notes that utilizing a pad in the interspace to separate the metatarsals in a gentle fashion will sometimes reduce the compression on the neuroma or the neuritis. Dr. Wernick usually asks patients to be quite cautious in regard to the shoes they utilize as a more flexible forefoot will tend to increase pressure to the neuroma site whereas a stiffer soled shoe will clearly increase the overall correction of the orthotic device.
The crest pad improves performance of the digits, thereby lessening the retrograde irritation that occurs with pathomechanically induced over activity, according to Dr. D’Amico. He notes that the orthotic device itself must realign the osseous and soft tissue structures, and promote normal function in order for any modification to achieve its full potential.
Dr. Beekman is a Diplomate of the American Board of Podiatric Surgery and the American Board of Podiatric Medicine. He is also a Fellow of the American Academy of Podiatric Sports Medicine.
Dr. Valmassy is a Past Professor and Past Chairman of the Department of Podiatric Biomechanics at the California College of Podiatric Medicine. He is a staff podiatrist at the Center for Sports Medicine at St. Francis Memorial Hospital in San Francisco.
Dr. Wernick is a Professor in the Department of Orthopedic Sciences at the New York College Of Podiatric Medicine. He is also a Diplomate of the American Board of Podiatric Orthopedics and the Medical Director of Eneslow Comfort Shoes and Langer, Inc.
Dr. D’Amico is a Professor and Past Chairman in the Division of Orthopedics at the New York College of Podiatric Medicine. He is a Diplomate of the American Board of Podiatric Medicine, and a Fellow of the American Academy of Foot and Ankle Pediatrics. Dr. D’Amico is in private practice in New York City.
For further reading, see “A Closer Look At Orthotic Solutions For Women’s Dress Shoes” in the December 2009 issue of Podiatry Today, “Inside Insights On Orthotic Modifications For Sports” in the October 2004 issue or “A Guide To Orthotic Treatment For Metatarsalgia” in the April 2012 issue.