Although many issues related to walking are benign, early recognition of these classic clinical presentations is essential for initiating further workup when indicated.
“Is it normal for my child to walk like that?” “Are my daughter’s legs supposed to turn in that way?” Concerns regarding the appearance of a child’s lower extremities are a common reason for visits to the pediatrician and a frequent source of orthopedic referrals.1 Musculoskeletal exam findings change as a child grows and develops. It is crucial for the pediatric clinician to be able to recognize normal pediatric orthopedic variants in order to differentiate conditions that can be treated with reassurance and education from those warranting further evaluation and workup. The aim of this article is to provide guidance on the diagnosis and management of 7 common lower limb positional variations in children and adolescents (Table).
Accurate diagnosis of rotational and angular problems starts with a detailed history. Is there a family history of pediatric orthopedic or neurologic issues? Does the limb appearance or the way the child walks resemble anyone else in the family? Oftentimes, a sibling walked the same way or a parent will describe having bowed legs or knock knees as a child but outgrew it. How long has this been a concern, and does it seem to be improving or worsening over time? Are there any systemic signs such as fever or fatigue? Ask about pain, falls, and tripping. Inquire about underlying nutritional issues, growth concerns, developmental delay, and history of injury.2 These can be red flags of something other than a normal variant.
Physical examination includes a generalized musculoskeletal examination, and should always include observation of gait and rotational profiles of the legs.3 Key assessment points are: 1) foot progression angle; 2) internal and external rotation of the hips; 3) thigh-foot angle; 4) heel bisector; and 5) limb position and arch appearance while standing in bare feet.
The foot progression angle (FPA) describes the inward or outward position of the foot relative to the direction of ambulation. Watch the child walk. Focus on 1 foot at a time and observe them walking toward you as well as walking away from you. Inward FPA is quantified in negative degrees (ie, internal tibial torsion [ITT] has an FPA more negative than -10°) or outward (positive value). Normal FPA ranges from -5° to +15°.4 Slight out-toed gait is most common. Keep in mind that FPA does not identify the source of limb rotation, however, it helps quantify severity and can be monitored for change.
Rotational profile of the lower limbs is best assessed with the patient in the prone position with the pelvis flat to the table. Internal rotation, external rotation, and thigh-foot angle should be evaluated. Internal rotation increases over childhood, peaking in mid-childhood at ages 6 to 8 years.4 This explains the normal variant of femoral anteversion during that time. External rotation is greatest in the newborn and then declines rapidly. This also explains the common finding of outtoeing in infants/toddlers.
Thigh-foot angle (TFA) compares the axis of the thigh with the axis of the foot (heel bisector). With the patient prone and knees flexed to 90°, the ankle is put into a natural position. If the foot points outward, the angle is positive, and if it points inward, the angle is considered negative—just as is done with the foot progression angle. A thigh-foot angle that is inward at least -10° is consistent with internal tibial torsion.3
Examination should include inspection of the lower limbs and feet both at rest and during motion. While seated, the heel bisector can be determined by drawing a line through the mid-heel up through the forefoot. A normal heel bisector should go between toes 2 and 3. Metatarsus adductus will present with a heel bisector that extends more laterally through toes 3, 4, or 5, and the lateral border of the foot will be convex rather than straight.
Red flags include an asymmetrical deformity, leg length discrepancy, limitation in joint movement, tenderness, pain with range of motion, and short stature (<25th percentile).5 In these situations, consider further evaluation including but not limited to radiographs and lab work (calcium, vitamin D, alkaline phosphatase, phosphorus, for example).