A Closer Look At Orthotics For Pediatric Conditions

Author(s): 
Guest Clinical Editor: Eric Feit, DPM

   While one must take special considerations into account while prescribing orthotics for children, different pediatric conditions also warrant special care. Following up on the previous discussion of pediatric orthotics (see “Expert Insights On Prescribing Pediatric Orthotics,” page 24, February issue), our expert panelists discuss key orthotic pearls in treating metatarsus adductus, abnormal femoral torsion and flatfoot in the pediatric population.    Q: Are orthotics helpful for a rigid metatarsus adductus foot type?    A: Richard Jay, DPM, Alona Kashanian, DPM, and Ronald Valmassy, DPM, agree that orthotics can be useful in treating patients with rigid metatarsus adductus. Dr. Kashanian says an orthotic can reduce stress on the lateral column when one utilizes a rearfoot post that is extended laterally but is not beveled laterally. She adds that a forefoot varus post helps support a structurally elevated first ray.    While Dr. Jay believes that orthotics are indicated in patients with rigid deformities, he notes that children may complain of discomfort at the base of the fifth metatarsal laterally. Accordingly, he says it is imperative to use an insert that does not have any high phalange against the fifth metatarsal base. Dr. Jay notes it is usually indicated to cut out the lateral area to allow exposure of the styloid process of the fifth metatarsal.    When patients have rigid metatarsus adductus, Dr. Valmassy says correcting the abnormal foot function with orthotics will reduce secondary symptoms often associated with the deformity. For many children who have a metatarsus adductus with a forefoot valgus deformity, he notes correcting the valgus deformity will not only cause the foot to function in a more stable manner but may also reduce the overall adducted appearance of the foot in gait.    However, Russell Volpe, DPM, says orthotics will not help a rigid metatarsus adductus. He says these children “will have a great deal of difficulty tolerating attempted correction with orthoses.” For these patients, Dr. Volpe says one would use orthotics more to accommodate prominences and deal with issues of symptoms on ambulation.    Q: Do you prescribe orthotics for patients with abnormal femoral torsion? Why and what type of device should one use?    A: Dr. Jay has found orthotics to be helpful for abnormal femoral torsion. Whenever there is femoral or tibial torsion in the axial segment, there will be a resulting internal torque through the foot, according to Dr. Jay. He says this creates a pronatory drive through the ankle joint into the talus. When these patients plant the foot firmly on the ground, Dr. Jay says the foot is abducted underneath the adducted talus. When using an orthotic for these patients, Dr. Jay says the goal is to prevent any abnormally excessive amount of pronation.    If you are using the insert alone to reduce pronatory change, Dr. Jay advises cautioning parents that although their children can expect an increase in the in-toe deformity, the treatment will prevent the foot from becoming permanently fixed and flattened.    Modifying orthotics with a gait extension to induce out-toe can help in-toe gait from femoral or tibial torsion to some degree, according to Dr. Volpe. When extending past the MPJs laterally, the distal, lateral extension on a relatively rigid shell will alter the break in the child’s flexible shoe during propulsion and subsequently encourage more out-toe with push-off. However, Dr. Volpe agrees with Dr. Jay about the importance of tempering parents’ expectations.     “I explain to parents that there will likely be improvement in gait that hopefully reduces instability and tripping,” says Dr. Volpe. “However, I also make sure it is clear to them that the device is primarily intended to improve function and is not a treatment of the underlying torsion.”    For children with in-toe gait, Dr. Volpe emphasizes the importance of using orthotics to protect the foot from the abnormal pronatory compensations one frequently finds with closed-chain internal torque from the leg. Employing motion-controlling devices for these children tends to increase the amount of in-toe as a pronatory compensation and reduces the abductory component, according to Dr. Volpe. He says one can manage that condition by combining the gait extension with positive modifications to reduce pronatory compensations in contact and midstance.    Dr. Valmassy prescribes functional foot orthotics for patients with an abnormal femoral torsion if he finds compensation within the subtalar and/or midtarsal joints. If the child has an adducted gait pattern due to a femoral torsion issue but has a fairly stable foot without compensation, he usually does not treat him or her with an orthotic device. Dr. Valmassy finds that type of gait pattern to be quite stable and says it does not precipitate any pain, discomfort or any secondary musculoskeletal problems.    When there is foot compensation for a transverse plane deformity, Dr. Valmassy says he addresses this with a more rigid type of functional foot orthosis. As the child grows older, Dr. Valmassy may use an out-toe gait plate to improve the foot’s appearance and possibly assist with stretching some of the secondary soft tissue adaptation which occurs secondary to a femoral torsion issue.    Children with internal femoral torsion have a history of frequent falls and are clumsy with sports and running, according to Dr. Kashanian. She emphasizes a thorough diagnostic exam to rule out a metatarsus adductus. She also assures parents that 80 percent of the deformity will correct itself. Dr. Kashanian tells patients to avoid sitting in the W position and encourages sports like roller blading or ice skating, which will force an external torsion at the hips.    Q: How do you prescribe an orthotic for a pediatric flatfoot? Do you believe in inverting the device based on the resting calcaneal stance position? Why or why not?    A: When prescribing an orthotic for pediatric flatfoot, Dr. Valmassy begins with a complete lower extremity musculoskeletal examination that includes a complete muscle testing examination and gait evaluation. He prescribes an orthotic that will be typically inverted to a significant degree in order to increase the heel contact control of the child’s foot.     “Many of the children that we evaluate have resting calcaneal stance positions in excess of 8 to 10 degrees of eversion,” points out Dr. Valmassy. “Clearly, this is a more challenging type of foot to address.”    For a severely pronated pediatric flatfoot, Dr. Valmassy usually utilizes a Root type of functional foot orthosis that is inverted approximately 10 degrees. He normally uses a 6 mm Kirby or medial heel skive, a 20 mm to 22 mm heel cup and a flat rearfoot post. Dr. Valmassy often uses a medial flange and may incorporate an accommodation at the level of any existing navicular prominence.    In addition, Dr. Valmassy uses a Blake inverted type of functional foot orthosis. With this device, he typically prescribes a 55 degree inverted orthotic with a 6 mm Kirby or medial heel skive, a deep heel cup, a flat post and a medial flange.    When treating both pediatric flatfoot and a severely pronated flatfoot, Dr. Valmassy says the inverting force is essential to correct the child’s foot. He emphasizes that one must explore all factors leading to the pediatric flatfoot, paying specific attention to tight posterior musculature. Dr. Valmassy encourages clinicians to constantly monitor the child’s response to the orthotic. If the device is ineffective in arresting abnormal foot function or symptomatology, Dr. Valmassy says one may need to consider surgical intervention.    Physicians frequently ask Dr. Kashanian how much to skive and/or invert the pediatric flexible flatfoot. As she explains, the pediatric flexible flatfoot demonstrates a calcaneal resting position of 2 to 10 degrees of eversion and the forefoot is abducted to the rearfoot during gait.     “The appropriate prescription for this foot type is a polypropylene device with a deep heel cup and an extra wide arch,” says Dr. Kashanian. “Both of the above dimensions allow more surface area for the orthotic to exert on the hypermobile flatfoot.”    She highly recommends using a minimal plaster cast arch fill, which allows maximum control on the medial column and prevents the midtarsal joint from unlocking and pronating. One would utilize the medial heel skive and inversion of the positive cast together to control the everted calcaneus and pronated subtalar joint, according to Dr. Kashanian. As far as the amount of medial heel skive and positive cast inversion to use, see “Key Orthotic Considerations For Pediatric Flatfoot” above.    When it comes to young children, whether they are infants, adolescents or young teenagers, Dr. Jay feels one should maintain inserts in an approximately 5-degree rearfoot varus posting alone without forefoot posting. He says the talus will go through a valgus ontogeny or, in other words, will rotate inward and down to bring the first ray down in more of a plantarflexed position and eliminate any forefoot varus.     “Placing forefoot varus posts will create an abutment or a brace to prevent the downward ontogeny of the talus and a rigid forefoot varus may result,” says Dr. Jay.    When treating these children, Dr. Jay typically prescribes an inverted heel seat as seen on the Langer Dynamic Innersole System. He also may use a deep-seated heel orthotic with a rearfoot varus post of 5 degrees.    Dr. Volpe advises taking a quality impression in subtalar neutral with a rectus forefoot and dorsiflexion of the hallux to increase the arch. One should limit plaster additions to the positive cast as they tend to reduce arch height. He also suggests using non-compressible shells and incorporating deeper heel seats and flanges when appropriate.    To improve weight transfer through the foot consistent with the tissue stress model, Dr. Volpe recommends adding plaster positive modifications such as medial skives, slight inversion of the cast and calcaneal pitch.    Inverting the cast to treat more severe deformities with higher calcaneal eversions can be effective in increasing arch height and improving weight transfer in the more severely pronated foot, according to Dr. Volpe. Dr. Feit is a Fellow of the American College of Foot and Ankle Surgeons, and practices privately in San Pedro and Torrance, Calif. He is the Past President of the Los Angeles chapter of the American Diabetes Association. Dr. Jay is a Fellow of the American College of Foot and Ankle Surgeons. He is a Professor of Foot and Ankle Orthopedics at the Temple University School of Podiatric Medicine and is board-certified in foot and ankle surgery. Dr. Jay practices at Cumberland Orthopedics in Vineland, N.J. He is the author of “Pediatric Foot and Ankle Surgery,” which is published by Saunders/Elsevier. Dr. Kashanian is a Diplomate of the American Board of Primary Medicine and Podiatric Orthopedics, and is a consultant for ProLab Educational Institute. She is also in private practice in Northridge, Calif. Dr. Valmassy is a 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. Volpe is a Professor in the Departments of Pediatrics and Orthopedics, and is the Chairman of the Department of Pediatrics at the New York College of Podiatric Medicine. He has a pediatric foot and ankle specialty private practice in Farmingdale and New York, N.Y. Editor’s Note: For other articles and columns on orthotics, check out the archives at www.podiatrytoday.com.

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