As PTs, we have all seen flat feet, pronating feet, varus feet, and many other varieties of feet. Many adults have flat feet, have no signs or symptoms of pain, and never seek treatment for their flat-footedness. Therapists study gait and its components, and most adults ambulate with some form of a “heel-toe” pattern. Pediatric therapists repeatedly answer the questions posed by concerned parents about how flat their child’s feet look. Should their child wear shoes? Why is their child’s foot so flat? Do they need arch supports?
As therapists, we often question the developing child’s foot position. How do you know when to help lift the arch of a flat foot? Is the calcaneal valgus observed controllable with a shoe insert, or does it need something more? Could our physical therapy interventions alone change the shape of the foot? We have seen children in which we have to question if the pronation is more than what is expected for their developing age. This article will describe how the foot and arch develop in early standing and walking, and will identify a process of orthotic selection and physical therapy interventions to correct a flat foot if indicated.
FOOT DEVELOPMENT
A newborn’s foot is very elastic. The plantar-flexion range is normal, but dorsiflexion can be as much as 45º secondary to the intrauterine position, and toes are very mobile. Forefoot adduction is slightly greater than abduction. The first and second metatarsal heads are longest and equal in length. The remaining metatarsals are adducted 15º to 35º. The sole of the foot appears triangular, wider anteriorly, and narrow in the heel. The longitudinal arch is present in the preambulatory foot, although it is hidden under the fat pads.1
Around age 1, when a toddler normally starts walking, the foot skeleton consists of a number of partially ossified centers connected by soft tissue. The fat pad, which gives the appearance of a flat foot, serves to protect the pediatric foot from overloading until the skeletal system has adapted to the vertical load during stance and gait. The physiologic pronation of the infant’s foot places strain on the medial connective structures, which respond by thickening and gaining strength to resist pronation. After the age of 2, with consistent and repeated standing and walking, the fat pad begins to be reabsorbed by the surrounding ligaments and ossification of the foot skeleton occurs. The medial longitudinal arch is not fully developed until as late as 6 years of age.2,3,4
Characteristically, a toddler’s gait is high guard arm position, wide base of support, small step lengths, flat foot contact, and vertical tibia throughout the stance phase. A toddler’s gait is highly variable, as seen in a study by Hallemans et al, where they observed three different contact patterns: initial forefoot contact, flat-foot contact, and heel contact. A roll-over, or heel-to-toe, pattern was seen in all three of the contact patterns by heels lifting off the ground to pushing off of the hallux. Initial heel strike with a roll-over of the foot evolves around 18 months of age.5 After 1 year of walking, the heel and forefoot region sustain significantly higher contact area, maximum force, impulse, and peak pressure. These changes are due to a load shift from the midfoot to the adjoining areas.
The results from the Bertsch et al study reveal that the midfoot initially bears 30% of the total load, decreasing to 17% within the first year of independent walking.2 Hallemans et al’s findings conclude there is a rapidly changing 5-month span after initial onset of walking where a roll-over was observed and improvements in balance were made. Balance changes observed were increasing step length, knee extension to perform heel contact, decreasing oscillations in the center of pressure measurements, and an increase in walking speed. They also concluded that subtle morphological changes in the foot that can affect the load distribution take longer to evolve.4 Mature ambulation at adult speeds, contact-pressure areas of the foot, arm swing, and muscle activation are seen only after 8 years of age.
ABNORMAL FOOT DEVELOPMENT
Pronation is a triplanar movement consisting of calcaneal valgus, midfoot eversion, and forefoot abduction. Bernhardt states the most frequent compensation for soft tissues or osseous deformities is abnormal pronation. Pronation can occur either too early or too late in stance phase, or it can be excessive. In each condition, the flexible flat foot is unable to absorb the forces of weight-bearing effectively. The excessive pronation is persistent and alters the arthokinematic relationships of the tarsal and metatarsal joints. This alteration of anatomical function may result in pathological conditions if untreated.1 This abnormal pronation can be concerning because if left untreated, it could potentially affect other joints, proximally altering body mechanics and causing pain and discomfort throughout life.
PHYSICAL THERAPY INTERVENTIONS
Often, we do not have the luxuries of pressure testing and gait analysis in clinic, but a good understanding of development and anatomy will help in your evaluation of foot position and function. The following interventions are not all-encompassing—and it is beyond the limits of this article to include all exercises and interventions for flat feet—but they can be used as a reminder of some important options in your treatment. As always, a thorough evaluation should be the guiding force in your treatment sessions.
We have discussed how the weight is distributed through the medial aspect of the foot of a child who has flat feet. Performing activities to help alleviate that weight-bearing surface, shifting it from medial to lateral, must be included in the treatment plan regardless of your orthotic intervention. When the child is first standing, simple weight shifts over the lateral border of their feet can be performed and will help them move into cruising.
Strengthening and balance training will simultaneously happen with lateral weight shifting but may need more attention. Single-leg stance with eyes open/closed, uneven surfaces with eyes open/closed, targeted muscle-strengthening exercises that are based from your evaluation, and other balance exercises can help build the intrinsic foot musculature and give proprioceptive feedback on foot position.
Taping the foot into correct alignment is another intervention, and it can be used to assess possible effects of orthotics. Therapists can tape the foot into a neutral foot alignment during the treatment sessions, or send the child home and to sports activities to help decide if orthotic intervention might be needed. Families can also seek wearing more supportive shoes and sneakers with a built-up arch before purchasing an over-the-counter insert.
ORTHOTIC INTERVENTION
Therapists need to consider when the child started standing and ambulating, giving the arch time to develop, before turning to orthotics. If, however, a child is not developing an arch and needs to have some support to correct foot alignment, the most minimal is the shoe insert. Inserts can range from flexible with minimal support to rigid with complete support. They can be generically sized to custom made. Inserts can help the hindfoot maintain subtalar neutral, provide arch support to pronating feet, and provide proprioceptive feedback improving foot position and balance.
Clinic-made inserts are a good option for use in younger, lighter children with slight pronation and can provide proprioceptive feedback for correct foot alignment. Made from simple materials like cork, dense foam padding, and tape, these inserts can alleviate the medial weight-bearing surface of the foot by dropping the lateral border of the foot, along the fifth ray and calcaneus, and adding medial support with pieces of material. They can help to decrease toe grab by cutting out the area under the metatarsal heads. These inserts can be made within a treatment session and can help lower the cost for a family whose child has a rapidly growing foot, or can be used as a test trial for a more custom-fit orthotic.
A relatively new orthotic option claims to be more dynamic by compressing the soft tissue by serving to self-post the foot within the flexible plastic. This type of orthotic allows for push-off by having the metatarsal heads free. It improves alignment with total foot contact and reduces pressure spots that a more rigid orthotic can create. This type of orthotic can be a good choice for children with calcaneal valgus and pronation, and for a hypotonic child with ligamentous laxity. If you have an active child, a more rigid orthotic could interfere with running and jumping activities. This orthotic, with its reduced trim line under the first ray and metatarsal heads, might be a better option for your child. If you have a heavier child or one with tone and strong fixing patterns, it is better to stay with a heavier plastic and a more static-positioning orthotic.
Of course, if the child has a known neuromuscular disorder and spasticity is involved, orthotic intervention should take place as soon as they are weight-bearing to avoid abnormal muscle forces acting on bony alignment. Arch supports can help maintain correct foot alignment on children with a flexible pes planus, which is when the longitudinal arch flattens during standing but is present during nonweight-bearing activities. Arch supports can also be useful in the uninvolved side of hemiplegic patients who medially weight-bear to compensate for unequal leg lengths or have laxity in the foot.
It is important to remember that when a child has delayed walking milestone, the intrinsic foot musculature and dissolution of the fat pad are subsequently delayed. Therefore, the foot will appear flat. But if given time to develop—at least 5 months of walking—an arch should start to appear. As therapists, we do not like to sit back and watch abnormal pulls on the body structure cause long-term malformations. But after this review of foot and arch development, maybe we will not leap in too fast but let nature take its course in a normal-developing foot.
Kelly Bossola, MS, PT, has been a therapist for 5 years. After graduating from Regis University in Denver, she started pediatric work in early intervention and schools in Virginia. In August 2003, she joined the staff at Children’s Hospital of Pittsburgh. She can be reached at .
REFERENCES
- Bernhardt D. Prenatal and Postnatal growth and development of the foot and ankle. Phys Ther. 1988;68:1831–1839.
- Bertsch C, Unger H, Winklemann W, Rosenbaum D. Evaluation of early walking patterns from plantar pressure distribution measurements. First year results of 42 children. Gait Posture. 2004;19:235–241.
- Frost HM. Intermediary Organization of the Skeletons, Vol 2. Boca Raton, Fla: CRC Press; 1986.
- Hallemans A, De Clereq D, Van Dongen S, Aerts P. Changes in foot-function parameters during the first 5 months after the onset of independent walking: a longitudinal follow-up study. Gait Posture. 2006;23:142–148.
- Hallemans A, Aout K, De Clereq D, Aerts P. Pressure distribution patterns under the feet of new walkers: the first 2 moths of independent walking. Foot Ankle Int. 2003;24:444–453.
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