By Patricia C. Winders, PT, Denver, CO
Editor’s note: Since 1984, Patricia Winders has worked with babies and children with DS as a physical therapist at Kennedy Krieger Institute (Maryland) and its Down Syndrome Clinic and now at the Sie Center for Down Syndrome, The Children’s Hospital, Aurora, CO. Winders is the author of Gross Motor Skills in Children with Down Syndrome: A Guide for Parents and Professionals (Woodbine House); a member of the NDSC Professional Advisory Council and will present a workshop at the NDSC Convention in Sacramento.
What causes flat feet in children with DS?
Individuals with DS are at risk for foot problems due to hypotonia and ligamentous laxity. Both characteristics contribute to joint hypermobility. This means the foot bones (see photo—pick 019 or 020) are not properly stabilized and aligned for standing and walking. Without taut ligamentous support, the heel (calcaneus) tilts inward and the surrounding bones (talus and navicular) follow. When the inside borders of the feet collapse to the ground, it gives the appearance of no arch (see photo 001). The degree of flat footedness varies from person to person. If it persists without treatment, the child may have further ankle and joint deformity. Long-term use of this standing and walking pattern will lead to pain.
Why is flat footedness a problem?
When the child walks with this posture, she bears her weight on the inside borders of her feet, walking with a wider base and turning her knees and feet outward (see photo 002). This inefficient walking pattern forces her to take shorter steps and walk more slowly. She doesn’t learn to rotate her pelvis on her trunk and the muscles have to work harder because the bones are not optimally aligned. The child must use more energy to walk and fatigues more quickly. She tends to use a heavy-footed pattern and sometimes slaps her feet. As the child grows, the increased weight on the ligaments stretches them even further. If the foot posture collapses more, causing malalignment in the knees and other joints, it alters body mechanics and compromises how the child runs, jumps and balances.
What can be done about it?
There are many possible treatment strategies for flexible flat feet, depending upon the individual’s age and needs. The treatment goal is to provide the right support to facilitate an efficient walking pattern with optimal alignment in the legs and feet (see photo 003). This achievement gives the foundation for the child to participate in physical activities he chooses. Any foot management strategy needs to consider both the type of shoe and the type of support in the shoe. In addition, practicing gross motor skills develops strength in the desired movements since the child needs to dynamically use the foot support to fully benefit from it. Running, walking on uneven surfaces and up and down inclines, kicking a ball, rising up on tiptoes, jumping, climbing stairs, stepping up curbs and working on balance skills are all good activities to promote.
The shoes the child uses for physical activity need to have soles that are very flexible in the toe box area so minimal force is needed to use toe push off (see photo 029). The child will not push against stiff soles to break them in, so movement is limited. The shoes also need to have firm medial and heel counters, which vertically support the foot in the shoe. With a flimsy heel or medial support, the shoe will probably tilt inward to take the shape of the child’s foot posture. Lace-up shoes are best to hold the foot over the support since it’s difficult to tightly close Velcro and the foot tends to tilt.
What types of supports are available?
There are many types of supports including a variety of orthotics (plastic foot supports), shoe inserts and arch supports. The foot support team can include the PT, orthotist, pediatrician, orthopedist, child and parents. The products need to be tested with each child for effectiveness and modified until the desired results are achieved.
In my experience, children generally tolerate flexible supports better than rigid ones. The type of support needs to be decided on a case-by-case basis considering 1) the degree of ankle and knee deformity and how it impairs walking; 2) the individual’s size and weight; and 3) what is appropriate for age and activity level. These are all important factors; however, the most important factor is whether the individual will tolerate the support because the support won’t help if the individual won’t wear it.
If the child is a new walker and able to walk independently on level surfaces, the most direct way to optimally support the foot is to stabilize the heel in the midline toward the vertical position. This lifts the collapsed bones to create a mild arch to the foot. However, the heel support needs to allow it to move within a mild range in and out of the midline. This is best achieved with the Sure Step Dynamic Stabilizing system (see photo 023) (www.surestep.net). This system stabilizes the foot and ankle by compressing the foot into alignment by using an extremely lightweight, thin and flexible plastic (unique patented design). It allows for more natural foot and ankle movement while still maintaining proper alignment when standing, walking and running. This system has specific trimlines (patented design) so the toes are free for squatting, jumping and running. In my experience, children tolerate these orthotics well since they do not feel restricted. Children learn to flex the plastic (to do gross motor skills) while benefitting from the optimal alignment and stability provided. Over time, the child learns to use an efficient walking pattern with toe push off and the child’s endurance improves.
There are many varieties of inserts or arch supports that can be used if the child needs less support. Orthotists can custom make a support or fit an off-the shelf model. Other types of supports can be purchased in shoe stores or drug stores. Inserts (for example, Cascade dafo “Hot Dog” insert (see photo 031) www.dafo.com) usually have a heel cup (a concave space for the heel) to support the heel’s center in a specific space. This allows the shoe to vertically support the heel. There is a medial longitudinal arch (some are filled with dense foam) which is long and wide to fully support the length and width of the arch. For individuals with DS, a flexible toe lever (support from the ball of the foot to the toes) is preferred. Supportive shoes provide the full benefit of the insert.
For some children and adults, the arch supports that already come in the shoes (like good supportive walking and running shoes) are adequate and comfortable for physical activity.
When do I check to see if foot support is needed?
After the child learns to walk, the foot posture and foot support should be assessed yearly to determine the individual’s needs. The foot management plan must be sensitive to the child’s weight, size and activity preferences, as well as the foot and leg posture while standing and walking. With the correct foot support, the child’s walking pattern will improve and the activity level will increase.
Some children need foot support prior to walking independently, but this needs careful evaluation, customized to the child’s general means of mobility and frequency of use.