Growth patterns in children produce changes in the feet and legs that often cause concern among parents. Flat feet, knock knees, or other conditions that indicate abnormalities in the mature body are a natural consequence of learning to stand and walk in the early years of life.
Health care professionals face something of a dilemma when dealing with pedal integrity in juvenile patients. If seeming abnormalities are dismissed as “normal growth patterns” there is a risk of overlooking a serious biomechanical defect. Likewise, immediately pursuing a therapeutic program of orthotic support, exercise, or other modalities may interfere with the child’s healthy developmental progress.
Trained observation and patience are keys to responsible care of the developing juvenile foot. Doctor, patient, and parents must be willing to watch, wait, and take appropriate action when signs and symptoms indicate the need for intervention.
Why Study The Feet?
The feet are the foundation of the body and a significant influence on total musculoskeletal health. The interrelationship of the feet to the body has been described as a closed kinetic chain (see Figure One). Movement at one link, or joint, affects others that form a continuous linkage from the feet through the ankle, tibia, knee, femur, hip joint, pelvis, and spine.1
When pedal biomechanics are disrupted, resulting pelvic and spinal distortion can lead to postural fatigue and spinal strain.2 The feet may feel fine, but nonspecific, chronic pain in other areas leads the patient to seek professional help.
Young children may not experience these types of painful symptoms, but their parents grow alarmed at perceived difficulties in standing and walking during the first six years of life. Knock knees, bow legs, foot flare, pigeon toes, flat feet, and abnormal gait are the more common signs that cause parents to seek biomechanical evaluation of their children.3
These concerns are generally well taken. Childhood pedal imbalance has been implicated in adult cases of low back, knee, and hip problems, postural fatigue, scoliotic deviations, and plantar fascitis.4,5 Early detection and treatment may help avoid a lifetime of pain and limited function.
Normal Foot Function
Before describing the phases of pedal development, it may be helpful to review the stance phase of gait, when the mature foot bears weight and performs its normal functions of locomotion and shock absorption. The process can be divided into three major components:6
- Contact: Heel strike begins, a natural inward rotation of the subtalar joint, called pronation. The tibia is pulled into the same rotation, allowing the knee to flex and effecting changes in the femur, pelvis, and spine. The pronation and knee flexion activate the body’s natural shock absorbers to protect the body from heel strike shock.1
- Midstance: Body weight shifts over the foot, which supinates as forefoot loading occurs. The tibia and femur rotate outward and the knee unflexes.
- Propulsion: This period of toeing off sees the foot in supination with leg bones externally rotated.4
Remember that these components describe a mature foot. In growing children, with varying capabilities of the feet and legs, deviation is not necessarily a sign of trouble.
Developmental Milestones of the Lower Extremities
Because the foot lacks a distinct architecture in the first 18 months of life,7 information in this article focuses on the child from about two years through six years of age. Indeed, more meaningful examinations can be conducted at age six or seven, when ossification of bony structures is normally completed and growth rates stabilize.4
At birth, a child exhibits effects of uterine crowding of the feet and legs: bowings, torsion, length discrepancies, and varus foot positions. At six months, the child may continue to exhibit bowed legs and toeing in as a result. Time usually resolves these biomechanical abnormalities.3
In the early weightbearing years, weight distribution is refined as the longitudinal arch develops. Foot loading is high in the midfoot and roughly equal across the metatarsals. With growth, midfoot loading decreases and the third and fifth metatarsals begin to carry more weight.7
This pattern creates the appearance of flat feet or fallen arches in the young child. A comparison measure of navicular tuberosities on a relaxed (pronated) foot and on a foot in the simulated neutral subtalar position is suggested as a test for clinical intervention. If the difference exceeds three eighths of an inch, treatment is recommended.3
Acceleration of growth rates after age three may cause knock knees and toeing in. From the bowed legs of birth, changes in knee posture are not uncommon among boys and girls, the latter occasionally changing from one knee posture to the opposite more than once. Measurements of total genu varum average ten degrees in the first year, six degrees at the fifth year, and three degrees at age 18.3
Examination of Gait Factors
A thorough examination of juvenile pedal integrity must also include a functional evaluation. Casual observation by a trained professional can reveal tendencies to foot misalignment during gait, uneven shoe wear, or any of several postural deviations related to motion.
When one or more of these “red flags” is detected, it is appropriate to conduct more precise testing and measurement. The procedures outlined below are most meaningful when repeated at regular intervals to determine developmental or therapeutic progress over the course of professional care.
One method of examination3 involves use of a tread mat or similar surface to record foot patterns during gait. For young children needing guidance, it is advisable to hold onto clothing behind the neck, as holding the child’s hand can affect results. Five key indicators can be observed from the single gait pattern:
- Gait angles. This measurement quantifies the degree of toeing in or out that a child exhibits. A line drawn on footprints from the center of the heel to the first interdigital space is compared with the long axis of the tread mat. This produces a distinct record so that left and right prints can be separately recorded and averaged and recorded with the date of testing. Standard measurements for the first year are eight to ten degrees; for the fifth year, four to five degrees; and by the 18th year, zero to two degrees.
- Step length. Aging and growth cause relative increases in step length, which is judged in relation to the patient’s height. Standards here refer to average comfortable speeds, because length tends to increase with speed of gait. Length is defined as the distance from a given point on one print along the axis of the tread mat, parallel to the same point on the accompanying contralateral print. Excepting the first step, all right and left prints are averaged together and compared to patient height. Average for the first year is one-fifth of height; for the fifth year, one-fourth of height; and by the seventh year, one-third of height. This is the ratio that tends to remain throughout adulthood.
- Base of step. Walking bases indicate problems of stability, changes in gait, toeing deviations, and neurological difficulties. Interpretation of measurements depends on correlation of other factors uncovered during a comprehensive examination. To measure base of step, extend the center heel mark along the tread mat axis to parallel the center heel mark of the companion contralateral step. All steps should be measured and averaged. The average standard for the first year is seven to five inches; for the second year, four inches; and for the third year, three to two and one-half inches, the average maintained throughout adulthood.
- Stance angle. This measurement reflects pedal structure and normally runs slightly higher than the total average of left and right gait angles. Several methods exist for capturing a print of both feet in stance, but the aim is to mark a line from the center of the heel through the first interdigital space. The bisecting lines from both feet are extended forward or back until they cross, forming an angle of in-toe or out-toe. At age one, the average measurement is 20 degrees, mainly out-toe. At age five, the average reduces to ten to eight degrees, either in- or out-toe. By age 18, average angle is four degrees and out-toe dominates.
- Scuffing. Some children create a short recurring smear on tread mat testing that should show improvement in progressive testing. It may occur as forward or backward scuffing at the heel or forefoot, or as lateral or medial scuffing. The motion is often undetectable in routine evaluations, so a markable surface like a tread mat is recommended.
Therapeutic Intervention
Many abnormalities detected in juvenile patients will resolve themselves with little more than a dose of “tincture of time.” The responsible practitioner should monitor the child’s progress in development of pedal structure and function, using methods described above to note improvement or degradation of abilities.
Hyperpronation is one of the leading foot problems detected among children in the elementary school years. Separate studies reveal that nearly a third of those aged 6 to 12 experience this imbalance.8In ideal standing posture, the feet evert to form an angle of 30 degrees, and a plumb line dropped from the sacral promontory falls midway between the feet onto a line between the navicular bones (see Figure Two).9 Pronation occurs when the superior aspect of the calcaneus tilts and rolls inward, bringing the talus with it. This releases the navicular from its arthrodial articulation with the talus and jeopardizes the medial longitudinal arch. When collapsed, it causes an anterior shift in weightbearing, and begins a serial distortion that may extend to the occiput (see Figure Three).10
Therapeutic orthotic support can limit the degree and duration of pronation in the juvenile foot.11This improves shock absorption and weight distribution to guard against plastic deformation of developing soft tissues. Joint stability is enhanced so that the lower extremities give optimal support to spinalpelvic structures.
A flexible orthotic enhances pedal support to encourage normal healthy development. An orthotic with leather bottoms with shock-absorbent heel pads withstand active wear while a moisture-resistant synthetic upper will promote comfort. If an orthotic is specially designed from weightbearing castings of the patient’s feet, it will work with the shoe and foot to provide functional biomechanical support for growing bodies.
Conclusion
Pedal dysfunction in juvenile patients is, to some extent, a natural consequence of maturation. The role of the health care professional is to monitor developmental progress against accepted standards of form and function regarding stance and gait.
In those patients who deviate from accepted norms, ongoing examination is of paramount importance. The use of a comprehensive battery of tests, repeated at regular intervals, allows a uniform, reliable evaluation of pathological conditions.
When hyperpronation causes pedal abnormalities, orthotic support can be prescribed to correct balance and alignment. Flexible orthotics made from weightbearing castings work with the foot to promote controlled function without restricting movement in the developing child.
References
1. Steindler A. Kinesiology of the Human Body Under Normal and Pathological Conditions, (ed. 3.) Springfield, Charles C. Thomas, 1970.
2. Schafer RC. Clinical Biomechanics. Baltimore, Williams & Wilkins, 1987.
3. Schuster RO, Skliar JD. Outgrowing Trends in Lower Extremities of Children. J Am Pod Med Assoc 1991;81(3):131-135.
4. Greenawalt MH. Children and Orthotics. American Chiropractor 1989; 4:46.
5. Caselli MA, et al. Biomechanical Management of Children and Adolescents with Down Syndrome. J Am Pod Med Assoc 1991;81(3):119-127.
6. Root ML, Williams PO, Weed JH. Normal and Abnormal Function of the Foot, Vol. II. Los Angeles, Clinical Biomechanics Corp, 1977.
7. Hennig EM, Rosenbaum D. Pressure Distribution Patterns Under the Feet of Children in Comparison with Adults. Foot & Ankle 1991;11 (5):306-311.
8. Notari MA, Mittler BE. Study of the Incidence of Pedal Pathology in Children. J Am Pod Med Assoc 1988;78(10):518-521.
9. Cailliet R. Foot and Ankle Pain (2nd ed.). Philadelphia: F.A. Davis, 1983.
10. Greenawalt MH. Spinal Pelvic Stabilization (4th ed.). Roanoke: Foot Levelers, Inc.,1990.
11. Christensen KD. Orthotics: Do they really help a Chiropractic Patient? ACA Journal of Chiropractic 1990;27(4):63-71.
