Educational

Most common foot types in Down Syndrome

There are six major categories of foot types (nolaro24.com) in the adult  population, each becoming apparent as early as age 6 or 7. When a podiatrist treats a patient with Down syndrome, whether an adult or a child, the biomechanics of the feet and lower extremities need to be analyzed closely and each patient needs to be foot typed. Frequently, patients with Down syndrome have a D foot type with a neutral to mildly compensated rearfoot and a neutral forefoot. As the child matures to adulthood, this foot type can often progress to an F foot type where the heel rotates even more, causing the person to strike the heel on the inside. This creates more collapse of the subtalar joint, which pulls the entire medial side of the kinetic chain downward resulting in genu valgus, knee torsion, and greater hip rotation. This is a very inefficient foot type causing early fatigue and muscle pain. (FIGURE 2) It’s like every step the child takes is in quick sand. Let’s quickly review the specifics of these two common foot types.

The D Quad Foot Type is a moderately over-pronated foot-type. This foot-type occurs when a Compensated Rearfoot Varus exists with a normal or neutral forefoot alignment. This foot type is congenitally a partially unstable foot and is often diagnosed in children as developmental flat foot. Make no mistake, if you think that this child will “out-grow the deformity,” just ask their biological parents, grandparents and older siblings to take off their shoes and socks. If family members demonstrate similar foot characteristics, chances are that this child is not going to develop an arch. During gait, this foot begins to pronate at the subtalar joint in contact phase, and continues to pronate throughout midstance. In propulsion, the 1st ray will plantarflex to load the medial column of the foot and allow the foot to re-supinate.

The F Quad Foot Type is commonly referred to as a Pes Planovalgus foot deformity because of its very poor alignment to the floor. This is a true “flat foot.” The condition occurs when a Compensated Rearfoot Varus is coupled with a large Flexible Forefoot Varus (also called Forefoot Supinatus).This foot type is the most hypermobile or flexible of the foot-types. This hypermobility leads to great instability throughout the foot and ankle, and can be prevalent throughout the body. These feet look “very flat” at an early age and can only worsen into adulthood. This severe instability also makes it difficult to develop and maintain core strength throughout the legs and trunk. Muscles need to work “overtime” to do the same job as someone with better functioning feet, drastically increasing energy expenditure. This foot-type causes a lot of damage to the forefoot during propulsion. In addition to transverse metatarsal arch reversal, don’t be surprised to see hammertoes, hallux abductovalgus deformity, functional hallux limitus, and painful corns and calluses.

Effects of the D & F foot (of those with Down syndrome) on the Kinetic Chain Let’s start with the knee. Len Leshin, MD, FAAP writes, “Instability of the patella (kneecap) has been estimated to occur in close to 20 percent of people with DS. The majority of cases of instability present only as kneecaps that can be moved further to the outside than the normal kneecap (subluxation); however, some people can have their kneecaps completely move out of position (dislocation), and some may even have a hard time getting it back into the right position. Mild subluxation of the kneecap is not associated with pain, but dislocation may be painful. While people with instability of the patella are able to walk, there is often a decreased range of motion of the knee, with an accompanying change in gait. The longer that nothing is done for the instability, the worse the condition will get over time. Orthoses (special braces) may be useful for mild cases, but severe cases require surgical correction.” 1

And finally we hit the back. Leshin adds, “Another condition associated with the spine in Down syndrome is scoliosis, which is the curvature of the spine to the side. While it appears to be more common in people with DS, the exact incidence isn’t known….Treatment of scoliosis remains the same as in other children, with bracing being the initial therapy, followed by surgical intervention if necessary.”1

The overall plan

Orthoses need to be specifically designed to improve coordination, balance, pain, posture, and strength, and to aid in the development of a more stable and functional gait. These orthoses should be comprised of a deep heel cup, a medial heel skive, and high medial and lateral sidewall flanges. (FIGURE 3) Control of the subtalar joint is paramount. Often kids are over-braced with AFO’s due to lack of foot control. By providing adequate foot control, SMO’s and AFO’s are often times not necessary. I find many children who are “over-braced” lack necessary joint movements and muscle development vital for normal growth and maturity.

Complementary solutions to Early Biomechanical Support

Physical Therapy progress typically associated with Down syndrome motor development is slow; and instead of walking by 12 to 14 months as other children do, children with Down syndrome usually learn to walk between 15 to 36 months. Specific physical therapy recommendations to consider, along with inserts/ orthotics/SMO’s, include: “Strengthening of lower extremity musculature (hips, knees,ankles, and feet) aimed at improving push off
and augmenting support of the knee joint. Heel cord stretching with the heel in neutral alignment when limited passive range of motion exists. Lastly, Dynamic balance activities, such as running or descending stairs, which encourage the child to shift their weight during late swing phase rather than waiting until heel contact.” 8 These are very good recommendations. I, along with many therapists in my area of practice, am seeing that when orthotic inserts are prescribed along with physical therapy, the improvement really sticks and builds. I see children in therapy all the time that have these everted/flat feet who just either never or too slowly build on strength absent there orthotics. Building better foundation helps those muscles move along faster.

Getting the Down syndrome Patient to Make an Appointment

But to treat a Down syndrome patient, you have to see them. That is where the education piece is so critical. In many of our communities, we have Early Intervention services for babies born prematurely or with medical concerns. This can be the place where an initial referral can originate. When an a therapist understands the importance of the feet and
biomechanics in the development of any child, she/he can screen for this. With early intervention, Down syndrome patients can have a better outcome in meeting their developmental milestones and lessening their risks of Alzheimer’s and obesity.

In Summary

So what can you do to help? As podiatrists, we are in the unique position of being trusted medical professionals of the lower extremity and its effects on the kinetic chain. This
gives us the ability to get out and educate, educate, educate. Preparing the community of people who work with the Down syndrome patients is the key to getting these clients proper foot care early in life in order to allow them a better chance at a long, healthy, active existence. “Treatment of painful feet in patients with Down syndrome is imperative because foot pain leads to relative immobilization and immobile retarded adults do not remain long in the community.”9 My goal as a practitioner and someone who recognizes the progression of foot types is preventing pain by knowing how to deal with it before it happens, coupled with improving overall biomechanical strength and structure. No matter a child’s medical diagnosis, it is important to educate parents and their children what their “foot type” is, and what that may bring them during their adult years.  Please feel free to reference my websites www.nolaro24.com and http://www.decaropodiatry.com for additional information regarding my practice and its methodologies.

 

References
1. Leshin, L. (2003). DS Musculoskeletal Conditions in Down Syndrome. In Musculoskeletal Disorders in Down Syndrome. Retrieved May 25, 2012, from www.ds-health.com/ortho.htm.

2 Rogers, C.: Carers Knowledge of common foot problems associated with people with Down’s Syndrome. University College Northampton, 2002.

3 Aprin H, Zink WP, Hall JE: Management of dislocation of the hip in Down syndrome. J Pediatr Orthop 5: 428, 1985.

4 Benoit, E.: Podiatry and mental retardation: The podiatrist’s role. J.A.P.A., 55: 434, 1965.

5 Young, E. (March 22, 2002). New Scientist. Down’s syndrome lifespan doubles. Retrieved June 5, 2012, from www.newscientist. com/article/dn2073-downs -syndrome-lifespan-doubles.html.

6 Eyman RK, Amer J Mental Retard, 95(6): 603-612, 1991.

7 Head, D., Exercise Engagement as a Moderator of the Effects of APOE Genotype on Amyloid Deposition, January 9, 2012.

8 Selby-Silverstein, L.: The effect of foot orthoses on standing foot posture and gait of young children with Down Syndrome. NeuroRehabilitation 16 (2001) 183-193.

9 Diamond, L.S. and Lynne, D. et al., Orthopedic disorders in patients with Down’s syndrome, The Orthopedic Clinics of North America 12(1) (1981), 57-71.