TOPIC 28: Lower Extremity Anomalies – Understand the evaluation and management of lower extremity anomalies in a young child (e.g., in-toeing, bowing, metatarsus adductus)
OFFICIAL ABP TOPIC:
Lower Extremity Anomalies – Understand the evaluation and management of lower extremity anomalies in a young child (e.g., in-toeing, bowing, metatarsus adductus)
BACKGROUND
Many lower extremity positional deformations are harmless and get better on their own as the child grows. While these may be monitored by the primary care pediatrician, a careful history and doing a thorough exam is important to spot any warning signs that need further evaluation or referral to a specialist.
COMMON LOWER EXTREMITY ANOMALIES IN CHILDREN
Metatarsus adductus: Metatarsus adductus is the most common foot deformity that babies are born with, occurring in up to 3% of full-term newborns. In metatarsus adductus, the forefoot curves inward while the back of the foot stays straight so that the foot forms a C shape.
IMAGE: www.pbrlinks.com/2025MOCA-MA1
Clubfoot: Clubfoot is characterized by excessive plantar flexion and medial deviation of the forefoot so that the sole faces inward. It may be positional clubfoot, which can be straightened to a normal position and usually resolves on its own. Congenital clubfoot cannot be moved into a normal position manually and usually requires casting and bracing.
IMAGE: www.pbrlinks.com/CLUBFOOT1
Positional calcaneovalgus feet: Positional calcaneovalgus feet are hyperdorsiflexed so that the top of the foot rests on the shin. This foot deformity is flexible and can be easily straightened out with gentle pressure. It usually resolves spontaneously without treatment.
Internal tibial torsion: Internal tibial torsion is the most common cause of in-toeing in toddlers. It causes the feet to turn inward when walking while the patellae point forward. It usually resolves on its own by five years of age.
IMAGE: www.pbrlinks.com/INTOEING1
External tibial torsion: External tibial torsion is the most common cause of out-toeing in young children. Like internal tibial torsion, external torsion typically resolves on its own over time, but it is more likely to cause knee pain or patellofemoral instability if it persists. Surgical treatment is usually not needed except in older children with persistent severe torsion.
IMAGE: www.pbrlinks.com/INTOEING1
Femoral anteversion: Femoral anteversion is characterized by increased internal rotation and decreased external rotation at the hip, typically noticeable after 3 years of age. The patellae turn inward when standing and walking. It also causes in-toeing and an “egg-beater” pattern during running where the legs swing in a circular motion. Children may have a preference for sitting in a W position rather than cross-legged. Femoral anteversion usually resolves on its own by 11 years of age and rarely requires surgery.
IMAGE: www.pbrlinks.com/INTOEING2
IMAGE: www.pbrlinks.com/INTOEING3
Genu varum (bow-legs): Genu varum, or bow-legs, is common in babies and young toddlers because of their fetal position in the uterus. Bowed legs usually resolve on their own by 2 years of age.
IMAGE: www.pbrlinks.com/VARUS1
Genu valgus (knock-knees): Genu valgus, or knock-knees, is normal in children 2–5 years old. It typically peaks at about 4 years of age and improves as the child grows beyond 4 years.
IMAGE: www.pbrlinks.com/VARUS1
EVALUATION OF LOWER EXTREMITY ANOMALIES
HISTORY
History should include:
- Age of onset
- Associated symptoms such as limp, pain, tripping, or falling
- Birth history, including risk factors for positional deformations such as low amniotic fluid or breech position
- Developmental milestones
- History of infection, trauma, or fracture
- Risk factors for rickets (sun exposure; calcium and vitamin D intake)
In-toeing is most commonly due to metatarsus adductus in children <1 year old, internal tibial torsion in children 1–3 years old, and femoral anteversion in children >3 years old.
PHYSICAL EXAM
Most of the common lower extremity anomalies can be diagnosed by physical exam:
- Plot length or height on growth charts (<3rd percentile suggests pathology).
- Assess symmetry of legs.
- Assess leg length.
- For foot anomalies, assess flexibility of the deformity.
- In metatarsus adductus, the heel bisector line is lateral to the second toe web space. Flexible metatarsus adductus: The forefoot can be easily abducted past the midline. Rigid metatarsus adductus: The forefoot cannot be abducted to the midline position.IMAGE: www.pbrlinks.com/2025MOCA-MA2
- Evaluate clubfoot to determine whether it is positional clubfoot or congenital clubfoot.
- For in-toeing or out-toeing, measure the thigh-foot angle while the child is prone and the knee and ankle flexed. Internal tibial torsion causes the foot to point toward the midline, while external tibial torsion causes the foot to point outward.IMAGE: www.pbrlinks.com/2025MOCA-TFA (thigh-foot angle)
- For bowing, extend the legs and rotate the patellae so they face upward. >6 cm of distance between the femoral condyles is considered abnormal at any age.
- Conduct a hip exam for internal and external rotation of the hips. Assess for developmental dysplasia in infants.
- In ambulatory children, observe lower extremity alignment of the patellae and feet while standing and walking.
- Perform a neurological exam, including reflexes and assessment for clonus.
Standing radiographs of the lower extremities should be considered for bowing that is suspected to be pathologic, such as short legs, asymmetry, or severe varus. Radiographs can help diagnose conditions like rickets or skeletal dysplasia.
MANAGEMENT OF LOWER EXTREMITY ANOMALIES
Lower extremity anomalies in children are usually benign, and most resolve spontaneously over time without treatment.
Red flags that may need further evaluation or referral to orthopedics include:
- One-sided or asymmetric deformity
- Short stature
- Leg-length discrepancy
- Deformity not improving as expected with growth or worsening
- Abnormal nerve or muscle findings on exam
- Severe in-toeing or out-toeing that limits function
- Severe bowing >6 cm between the femoral condyles
- Association with pain or limping
- History of lower-extremity fracture, infection, or tumor
Flexible metatarsus adductus resolves on its own by 1 year of age in 90% of cases. Rigid metatarsus adductus usually requires treatment with a series of plaster casts, but surgery is rarely needed.
Congenital clubfoot: Congenital clubfoot should be referred to orthopedics for casting and bracing and possible surgery depending on severity.
REFERENCES
https://www.uptodate.com/contents/lower-extremity-positional-deformations
https://www.uptodate.com/contents/approach-to-the-child-with-in-toeing
https://www.uptodate.com/contents/approach-to-the-child-with-bow-legs