Support for Using HeelRite™ Heel Seats for Infants with Overpronation Part 3

Author: Billi (Beverly) Cusick, PT, MS, NDT, COF/BOC

The popular notion that bare feet are best for babies does not apply to babies with overpronation. The sensory input the pronated foot delivers is altered and pathological. The strategies used all day for maintaining balance with pronated feet are altered and pathomechanical. These children benefit from the more ideal sensory input afforded by foot joints that are in more ideal alignment, whereby the weight loads on the feet are appropriate for fostering foot development and stability skills.

In 2020, PJ Bresnahan published this statement:

“Pediatric flatfeet should not be ignored or downplayed. The sooner effective treatment is prescribed, the less damage will occur to other parts of the body.  When possible, a more conservative corrective procedure should be performed prior to irreversible, joint destructive [i.e. surgical] options.” [1] 

THE RISKS AND POTENTIAL REWARDS OF EARLY INTERVENTION FOR OVERPRONATION

“…perhaps the most important treatment for the adult-acquired flatfoot is prevention. If the at-risk foot can be identified, early intervention might prevent the deformity.” [2]  

“Orthopedic shoes” - made with wedged, off-set Thomas heels and rigid arch supports - had no corrective effect on hypermobile overpronation in children because of deformation of the shoe over time. [3]  Their use was subsequently terminated. Since those days, physicians who dismiss parental concerns about early pronation presume that the child will outgrow the pronation, and so any type of orthotic intervention is

 unnecessary, expensive and often poorly tolerated. [4] These physicians choose to err on the side of reported trends in typical foot development without assessing the child’s motor skills, ankle dorsiflexion range of motion, triceps surae muscle tone, lower limb muscle strength, and fatigability. Many physicians do not relate complaints of growing pains to overpronated feet. This practice of dismissing them all as “normal” leaves those who cannot self-correct unattended, and a preventative opportunity is lost.  

EJ Harris (2021) - no fan of early intervention - stated that there are no reports
 of adverse effects of intervening “unnecessarily” to address early overpronation.” [5]

Meanwhile, prefabricated, inexpensive in-shoe orthoses have been available since the late 1950s when AJ Helfet introduced and later patented his Heel Seat. [6] He recommended a constant wear time of two to two and a half years for the growing foot to acquire and sustain the medial arch.

In 1977, Bleck and Berzins determined that a pediatric talar body and neck plantarflexion angle (TPF) of > 35°  is a pathomechanical radiologic observation in standing position in early foot development. They investigated the effects of wearing prefabricated Helfet heel seats and custom-fabricated University of California at Berkley Laboratories (UCBL) [7] talus-control foot orthoses on the appearance of the feet and the TPF findings obtained in 71 children ages 1 to 8 years. The heel seat terminates at the distal calcaneus. The UCBL orthosis extends to the proximal metatarsal heads. Of this group of 71 children 79% showed improvement that increased the longer the devices were worn. [8]

Forty-one of the 71 children in Bleck’s study group wore Helfet heel seats that were exchanged to accommodate growth every 8 months on average. Their mean age was 4 years (SD 2.6 yrs, range: ~15 months to ~6,5 years). They wore the orthoses for an average of 13.3 months (SD 6.8 months, range: ~6 to ~20 months). They were re-evaluated 6 months to 6 years after discontinuing orthotic wear. Their mean TPF angle before intervention was 40.6° (SD 8.5). Seventeen (41%) of them had achieved a TPF angle of < 35° at follow-up. Eighteen (44%) showed improvement of > 3°. Six (15%) showed no change. 

The authors concluded that the Helfet heel seat is ~85% effective in reducing clinical and roentgenographic pronation with TPF angles of 35-45°. They recommended the UCBL for children with TPF angles > 45°. The overall rate of improvement was approximately 10 ° of TPF angle correction for every 2 months of wear.

Concerning the complaint about expense, Theologis et al (1994) found that of 52 children with hypermobile overpronation and markedly uneven shoe wear who were treated with Helfet heel seats for 18-36 months, 44 (84.6%) had improved shoe wear. “Simple heel seats offer economical treatment for children whose foot deformities destroy their shoes.” [9]

CONSENSUS: PODIATRIC CRITERIA FOR PRESCRIBING FOOT ORTHOSES FOR CHILDREN.
Until standardized assessments and data are acquired, we must lean on the other sources of evidence in treating early overpronation: the basic sciences - anatomy, kinesiology, biomechanics and physiologic adaptation to routine use - and clinical experience.  A group of 15 experienced pediatric podiatrists participated in a consensus study on the identification of overpronation and observations and goals that typically warrant prescribing foot orthoses (FOs).1  The following table is a sample of their results.

GOAL	AGREEMENT %
Reduce fatigue	85.7%
Improve gross motor skill	85.7%
Improve balance, stability, comfort, coordination, stamina	92.8%

 

CONSIDERATIONS FOR SELECTING THE HEELRITE™ HEEL SEAT FOR EARLY INTERVENTION
In 2014, after more than 50 years of making them and long after the patent had expired, the manufacturer of the Helfet™ Heel Seat terminated production. I had been using them successfully for several years, and along with many colleagues, experienced a loss after this event. As no prefabricated, heel-cupping option was available, Progressive GaitWays pursued the manufacture of a comparable replacement for several years. Under our company policy “Babies don’t wait”, we began producing the smallest two sizes for infants and toddlers with the type of flexible overpronation that occurs with hypotonia, ligament laxity and/or muscle weakness, and that can be manually corrected in standing position without force. 

Heel Seat Features & Mechanisms
Thin, flexible plastic encases the calcaneus - the anatomical key to load-bearing foot alignment. When the flattened, load-bearing heel seat base gains ground contact, the vertical walls surrounding the heel tip it upright on the base, lifting the sustentaculum tali up to the talus, reducing TPF angle and moving bodyweight backward and outward on the feet, reducing the load on the inner forefoot.  

The diagonal trim line at the front of the heel seat clears the way for the off-loaded first ray to plantarflex for ground contact. In this way, the long, medial arch of the foot is formed over time.

Limitations: HeelRite™ heel seats are not intended for those children with overpronation that is compounded by stiffness in the triceps surae muscles, compensatory stabilizing lower limb muscle coactivation as occurs in diplegic cerebral palsy, or involuntary movements seen in dyskinesia and dystonia.

The effectiveness of heel seats is compromised by flimsy foot attire. Please see optimum shoe features described below.

It is appropriate to introduce heel seat wear on a graduated wear schedule, 1 hour in the morning, 1 hour after noon, 1 hour after dinner for days, then twice the wear time for 3 days, then all day.

If the child with overpronation spends hours per day without wearing them, the accompanying or causative laxity and muscle weakness will persist and are likely to increase.  

Heel Seat Sizing: Find details on this web page

Optimum Toddler and Infant Shoe Features
Caregivers must provide appropriate shoes to complement the heel seats. Each pair of heel seats can be worn with a span of three assigned shoe sizes. Shoe sizes are the same without or with the heel seats, as they fit into shoes with no demand for larger space.
As our smallest heel seats will fit infant shoe sizes 3, 4, & 5 (for heel seat size 5) or sizes 4, 5 and 6 (for heel seat size 6),  we suggest that you provide shoes with these features:

• A sturdy heel box that feels stiff when you squeeze it
• A flat, sturdy sole that does not rock from side-to-sid
• A closure system that provides midfoot support

Here are some images of suitable shoes. Prices and size ranges vary. Search online for sources:

Heel Seat Benefits When Worn with Appropriate Shoes
I expect to see three or more of  these changes within 10 minutes of wear of the heel seats combined with sturdy shoes:

• More vertical heels. Bulging of the medial shoe diminishes.
• Inward deviation of the inside ankle bone medial (malleolus) diminishes.
• A narrower standing base of support – feet are closer together.
• A more erect posture with the heels taking more bodyweight.
• Increased standing stability.

More weight shifting and movement in the standing position. If they are worn consistently for up to three years, as in all day and off for bath, sleep, and time at a pool, heel seats can contribute to lasting improvements in foot alignment. [6] They should be replaced with the next larger size as foot growth demands. 

References
[1] Bresnahan PJ, Juanto MA. 2020. Pediatric flatfeet—a disease entity that demands greater attention and treatment. Frontiers in Pediatrics. 8:19.
[2] Greisberg J. 2007. Adult acquired flatfoot. In: DiGiovanni C, Gresiberg J. Core Knowledge in Orthopaedics: Foot and Ankle. Maryland Heights, MO:Mosby – cited by D’Amico JC et al in 2021.
[3] Helfet AJ.1956. A new way of treating flat feet in children. The Lancet. 267(6911):262-264.
[4] Harris EJ. 2010. The natural history and pathophysiology of flexible flatfoot. Clin Podiatric Med Surg. 27(1):1-23.
[5] D’Amico JC, Jarris EJ. 2021. Pediatric Overpronation: Treat or Monitor?
https://www.hmpgloballearningnetwork.com/site/podiatry/case-study/pediatric-overpronation-treat-or-monitor 
[6] Helfet AJ.1956. A new way of treating flat feet in children. The Lancet. 267(6911):262-264.
[7] Henderson WH, Campbell JW. 1967. UCBL Shoe Insert Casting and Fabrication. The Biomechanics Laboratory, Univ. CA at San Francisco and Berkley, Technical Report 53.
[8] Bleck EE, Berzins UJ. 1977. Conservative management of pes valgus with plantar flexed talus, flexible. Clin Orthop Rel Res. 122(Jan-Feb):85–94.
[9] Theologis TN, Gordon C, Benson MK. 1994. Heel seats and shoe wear. J Pediatric Orthop. 14(6):760-762.
[10] Sackett DL, Rosenberg WM, Gray JM, Haynes RB, Richardson WS. 1996. Evidence based medicine: what it is and what it isn't. British Med J. 312(7023):71-2. 
Ueki Y, Sakuma E, Wada I. 2019. Pathology and management of flexible flat foot in children. J Orthop Sci. 24(1):9-1