Expert Insights On The Use Of Orthotics For Equinus And Flatfoot

These knowledgeable panelists discuss the use of orthoses in the management of equinus, asymptomatic pediatric flatfoot and peroneal spastic flatfoot secondary to tarsal coalition.

Q:

What are your most effective orthotic treatments and modifications for patients with lower extremity equinus?

A:

Equinus may be one of the most destructive forces in the foot, asserts Joseph D’Amico, DPM. Russell Volpe, DPM, concurs. “If you miss the equinus influence during your biomechanical assessment, the patient has a much greater chance of having difficulty tolerating the (necessary) control the device is providing,” explains Dr. Volpe. “This is one of the most common reasons for patients who have difficulty tolerating controlling orthoses.”

Patrick DeHeer, DPM, emphasizes that one should treat equinus before utilizing orthoses. As he notes, equinus has distal compensation with plantarflexion of the naviculocuneiform joint. Dr. DeHeer says patients often cannot tolerate a rigid or even semi-rigid orthotic because of this pronatory moment the equinus is creating. When the equinus remains untreated, Dr. DeHeer says this is when you will commonly hear patients complain that the orthotics are “too high in the arch.” In these situations, he says the problem is rarely the orthotic but rather an untreated equinus deformity that one should treat non-surgically, most often via bracing, prior to orthotic use.

When it comes to equinus compensation caused by the gastroc soleus, the hamstring or iliopsoas contractures, Dr. D’Amico emphasizes appropriate stretching prior to and in conjunction with orthotic prescription to increase the likelihood of patient tolerance.

Dr. D’Amico notes the degree of orthotic control is dictated and limited by the ability of the individual to adapt to the device itself, which is influenced by the type and severity of equinus present. Dr. Volpe concurs. After identifying the equinus influence, Dr. Volpe says one must assess/design the orthosis/shoe complex to increase available (relative) dorsiflexion at the ankle in gait. He notes one can do this by adding heel lifts to the shoe combined with assessing the heel drop in the midsole of the shoe. The greater the heel drop of the shoe, the more the shoe is helping to neutralize the equinus influence, according to Dr. Volpe. He adds that barefoot and flat sole (zero heel drop) are often the most difficult for patients with equinus to tolerate.

Dr. D’Amico says heel elevations are beneficial for most equinus situations, especially when there is a bony block at the ankle and in cases of pseudoequinus. Elevation of the heel plantarflexes the forefoot and Dr. D’Amico says that sets a new lower sagittal plane starting point with a resultant increase in apparent dorsiflexory motion. He notes that allows the patient to more often tolerate control of oblique axis midtarsal joint pronation, even with a rigid to semi-rigid shell.

When it comes to heel lifts, Dr. Volpe also suggests considering the amount of room in the counter of the shoes where the device will sit. He notes shoes with a shallower heel counter will have more difficulty accommodating heel raises placed below extrinsic rearfoot posts. Equinus lifts should always be symmetrical unless there is an accompanying limb length discrepancy that is not equinus-related, according to Dr. Volpe.

Dr. D’Amico’s heel elevations range from 1/8 to ½ inch and he adds no more than ¼ inch to the orthotic, saying one can employ any additional amount of lift as an adjustable separate heel rise under the device that patients can discard in the future as the equinus situation resolves. He does not routinely use a completely inflexible or rigid shell for those individuals. Dr. D’Amico advises using materials with some flexural forgiveness such as high-density polyethylene, carbon fiber composites or polyolefins.

For Dr. D’Amico, a particularly useful and effective device in the equinus driven patient is the Dynamic Stabilizing Innersole System.¹ He notes the device’s unique orthotic design offers two independent medial and lateral control arms that provide sagittal plane “adjustability” while still providing significant control.  

In regard to intolerance of orthotics, Dr. D’Amico suggests first checking to make sure the patient is performing the posterior muscle group stretching and wearing the appropriate heel height with footwear that allows for flexible metatarsophalangeal joints. The next steps are increasing the heel elevation if possible and simultaneously heating the orthotic in the midfoot region to increase its sagittal plane flexibility. Dr. D’Amico says this promotes better patient tolerability.

Concurrent to the orthosis/lift/shoe therapy, Dr. Volpe will begin the patient on a stretching regimen for the tight posterior muscle(s) either at home or with the help of a physical therapist.

Q:

When do you treat the asymptomatic pediatric flatfoot with orthoses?

A:

Dr. D’Amico notes that all children are born with the potential for orthopedic foot problems related to weightbearing and the foot’s inherent structure.² He says weaknesses in the foot structure of the child are the predecessors of foot disability in the adult.

Dr. D’Amico clarifies that the absence of symptomatology is an unreliable indicator of optimum foot and limb function at any age and this is especially true in the pediatric population. As he explains, often symptomatology as a result of hereditary musculoskeletal imperfections is not apparent until the third or fourth decades or even sooner as commonly occurs following high school sports participation. Furthermore, Dr. D’Amico notes symptomatology created by excessive pedal pronation need not be in the foot but could be in the knee, hip or back secondary to attendant pathomechanical stresses creating malalignment and dysfunction in the superstructure.

Dr. D’Amico cites Herman R. Tax, DPM, often referred to as the Father of Podopediatrics, as stating, “There is a serious public and professional misconception confusing the problem of flatfeet with excessively pronated feet in children. However, flatness of the arch can be a normal or abnormal finding in foot posture whereas the excessively pronated foot is flat as part of a structural malposition that is present in the arch of most children and the basic reason for most postural pathology of the lower extremity.”^3,4

There are many factors that go into Dr. Volpe’s decision on when to treat an asymptomatic pediatric flatfoot, the first and foremost being the severity of the deformity. As he notes, one should treat more severe deformities earlier and more aggressively. The other major factor is an assessment of comorbidities that may be contributing to or aggravating the pediatric flatfoot. Dr. Volpe advises that the greater the number and severity of comorbidities, the greater the likelihood of progression to symptoms and/or structural deformities that one can manage with early orthosis use.

One should neutralize excessive pronation at any age and if it is visible, it is excessive, notes Dr. D’Amico.^5,6 Richard O. Schuster, DPM, also a pioneer in the assessment and management of pediatric orthopedic disorders, recommended treating the excessively pronated foot if the navicular differential or drop was greater than 3/8-inch or 9 mm with or without symptoms, notes Dr. D’Amico.⁷

According to Wolff’s Law of Bone and Davis’ Law of Soft Tissue, Dr. D’Amico says growth and development may facilitate a positive change in alignment and function as long as the patient wears the prescribed orthotic device faithfully and for a prolonged period of time.^8-10 He cites Rose as stating, “If the foot can put in a balanced stable posture and held in that position during the early years, cure will result.”¹¹ He notes Rose went on to state that since the rigid pes plano valgus can be so disabling and the treatment so readily tolerated, some degree of overcorrection is acceptable and desirable.
Additional considerations for Dr. D’Amico to treat the asymptomatic pediatric flatfoot include a positive family history of lower extremity musculoskeletal pathology, systemic disease, knee, hip or back pain, ligamentous laxity and other factors.  

Dr. DeHeer treats asymptomatic pediatric flatfoot deformity when the deformity is moderate to severe or if the child’s parents or siblings have foot pathologies related to pes planus. He will treat any equinus deformity in patients with flatfoot with stretching via a brace and will check the patient monthly until he or she achieves 5 degrees of dorsiflexion at the ankle with the knee extended and the subtalar joint in a neutral position with the midtarsal joint fully locked.

After correcting any equinus deformity, Dr. DeHeer will prescribe an age-appropriate orthotic and check the child every six months to evaluate for outgrowth. He typically recommends treating any pediatric patient with orthotics until he or she is skeletally mature.

Dr. Volpe often uses prefabricated devices in the youngest and less severe cases, and will consider moving to custom and more aggressive control as the child gets older.

“Children born today have the opportunity to live to be 100 years or more, and what will determine the quality of their lives when they reach 70 or 80 years of age is the ability to walk without pain and this starts with the feet,” says Dr. D’Amico. “Therefore, anything that can be done at an early age to improve alignment and function will reap huge benefits later on in life.”

Q:

How do you approach conservative management of peroneal spastic flatfoot secondary to tarsal coalition?

A:

Dr. Volpe emphasizes adequate imaging to try to identify the cause of the coalition and/or spasm. Ultimately, he says the best treatment planning depends on determining the cause of the coalition and the spasm. Treating the spasm and/or pain is important, but Dr. Volpe notes it is only the symptom or manifestation of an underlying etiology that one must identify in order to manage fully. Even after extensive imaging, Dr. Volpe says there are cases of peroneal spasm in which one cannot easily identify a cause or irritant, resorting in the practitioner addressing these cases on more of a symptomatic basis.

Dr. DeHeer notes that when treating a peroneal spastic flatfoot due to tarsal coalition, the initial concern is relaxing the peroneal spasm. He says this usually requires immobilization with a cast boot for two to four weeks with possible oral or injected steroids to reduce the inflammation. If the spasm resolves, Dr. DeHeer uses a low-Dye type of strapping to test for a custom orthotic. Dr. DeHeer notes one must treat any equinus deformity concurrently. If the spasm does not relax or orthotics do not prevent recurrence of symptoms, he says surgery may be indicated.

Dr. Volpe says a high peroneal block to break the spasm is often indicated and he may combine the block with a sinus tarsi infiltrate to treat localized rearfoot symptoms. Dr. D’Amico employs up to three weekly to biweekly subtalar joint injections of either Celestone Soluspan (Merck) 3 mg/Marcaine 2.5 mg or Kenalog (Bristol-Myers Squibb) 20 mg/Marcaine 2.5 mg depending upon local tenderness and severity of the spasm. If there is an absence of sinus tarsi or lateral talocrural pain or tenderness, he will administer a peroneal nerve block at the head of the fibula in an attempt to break the spasm. He sometimes utilizes the nerve block and the intrarticular injection together.

Dr. Volpe applies a below-knee cast with the foot out of spasm and as close to subtalar neutral as possible in order to calm the arthralgia down and attempt to reduce/block a re-spasm. After obtaining a satisfactory position, he moves the child to a custom foot orthosis to attempt to keep the foot out of spasm and reduce the symptoms associated with ongoing rearfoot motion. As Dr. Volpe notes, one may start with an orthosis from a partially pronated negative cast, depending on the degree of spasm reduction achieved prior to orthosis casting. He will attempt to move the patient to a more neutral custom device over time if the joint range of motion/position improves over time.

Supinatory exercises such as forceful inversion of the foot while sitting or standing and walking on the lateral border of the foot are helpful for Dr. D’Amico. He notes control of abnormal pronation and its attendant pathomechanics are essential in obtaining lasting spasm-free function.

A neutral subtalar joint impression cast may be initially difficult or impossible to obtain so Dr. D’Amico says one may have to stage the correction and inform the patient of the probability of needing a change in the prescription when the foot alignment improves. He notes the initial impression requires two people: the doctor to supinate the foot as close to neutral as possible and the assistant to stabilize the leg as a lever against which the foot can maneuver into its best possible position. Dr. D’Amico compares this to the inverted cast technique, first described by Whitman, in which the seated patient crosses the affected leg over the other with the foot resting on the opposite knee, resulting in a maximally supinated cast.¹²

Dr. D’Amico advises keeping the orthotic device itself particularly rigid and non-compressible with a deepened heel seat ranging from ¾ to 1 inch with appropriate and aggressive rearfoot and forefoot posting. To enhance control, he suggests employing a Kirby skive or Blake inverted cast technique.^13,14

In addition, he says a lateral flange or clip will keep the foot from laterally drifting off the device if the spasm has not completely resolved. Dr. D’Amico has had success with acrylic devices such as the original Rohadur or its descendants as well as carbon fiber composites and high-density polyethylene. He notes a particularly useful device in this instance would be the Dynamic Stabilizing Innersole System. If all else fails, he uses a University of California Biomechanics Laboratory (UCBL) device but prefers not to as the UCBL blocks all subtalar and midtarsal joint motion, thereby disallowing normal function.

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.

Dr. DeHeer is a Fellow of the American College of Foot and Ankle Surgeons, and a Diplomate of the American Board of Podiatric Surgery. He is also a team podiatrist for the Indiana Pacers and the Indiana Fever. Dr. DeHeer is in private practice with various offices in Indianapolis. Dr. DeHeer has disclosed that he is the inventor of the EQ/IQ equinus brace. Dr. DeHeer writes a monthly blog for Podiatry Today. One can access his blog at www.podiatrytoday.com/blog/289 .

Dr. Volpe is a Professor in the Department of Orthopedics and Pediatrics at the New York College of Podiatric Medicine in New York City. He is in private practice in New York City and Farmingdale, N.Y.

References

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5. Tax HR. An introduction to the study of children’s feet: part one. 1944. J Am Podiatr Med Assoc. 2007; 97(4):287-92.
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7. Schuster RO. Origins and Implications of Frontal Plane Imbalances of the Leg and Foot. Yearbook of Podiatric Medicine and Surgery. Futura Publishing, Mt. Kisco, NY, 1981.
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10. Mann RA. DuVries’ Surgery of the Foot, Fourth Edition. CV Mosby Co., St. Louis, 1978, p. 84.
11. Rose G. Pes planus. In Jhass MH (ed.) Disorders of the Foot. WB Saunders, Philadelphia, 1982, pp. 486-520.
12. Whitman R. Observations of forty-five cases of flat-foot with particular reference to etiology and treatment. Trans Am Orthop Assoc. 1889; 11(1):122-137.
13. Blake R. Inverted functional orthosis. J Am Podiatr Med Assoc. 1986; 76(5):275-276.
14. Kirby KA. The medial heel skive technique improving pronation control in foot orthoses. J Am Podiatr Med Assoc. 1992;82(4):177-188.