The femur is internally rotated (anteversion) at birth about 30 degrees, decreasing to about 10 degrees at maturity. The tibia begins with up to 30 degrees of internal rotation at birth and can decrease to a mean of 15 degrees at maturity.
Torsional variations should not cause a limp or pain. Unilateral torsion should raise the index of suspicion for a neurologic (hemiplegia) or neuromuscular disorder.
The family may give a history of W-sitting, and there may be a family history of similar concerns when the parents were younger. The child may have kissing kneecaps due to increased internal rotation of the femur. While walking, the entire leg will appear internally rotated, and with running the child may appear to have an egg-beater gait where the legs flip laterally. The flexed hip will have internal rotation increased to 80 to 90 degrees (normal 60-70 degrees) and external rotation limited to about 10 degrees. Radiographic evaluation is usually not indicated.
Internal Tibial Torsion
This is the most common cause of in-toeing in a child younger than 2 years old. When it is the result of in utero positioning, it may be associated with metatarsus adductus.
The child will present with a history of in-toeing. The degree of tibial torsion may be measured using the thigh-foot angle . The patient lies prone on a table with the knee flexed to 90 degrees. The long axis of the foot is compared with the long axis of the thigh. An inwardly rotated foot represents a negative angle and internal tibial torsion. Measurements should be done at each visit to document improvement.
Treatment of In-toeing
The mainstay of management is identifying patients who have pathologic reasons for in-toeing and reassurance and follow-up to document improvement for patients with femoral anteversion and internal tibial torsion. It can take 7 to 8 years for correction, so it is important to inform families of the appropriate timeline. Braces (Denis Browne splint) do not improve these conditions. The lack of improvement by 2 years of age for children with internal tibial torsion should result in referral to a pediatric orthopedist. Approximately 1% to 2% of all patients with in-toeing will need surgical intervention due to functional disability or cosmetic appearance.