summary Internal Tibial Torsion is a common condition in children less than age 4 which typically presents with internal rotation of the tibia and an in-toeing gait. Diagnosis is made clinically with a thigh-foot angle > 10 degrees of internal rotation in a patient with an in-toeing gait. Treatment is observation in most cases as the condition usually resolves spontaneously by age 4. Surgical management is indicated in children > 6-8 years of age with functional problems and thigh-foot angle >15 degrees. Epidemiology Incidence most common cause of in-toeing in toddlers Demographics usually seen in 1-3 year olds Anatomic location often bilateral Etiology Pathophysiology exact etiology unknown believed to be caused by intra-uterine positioning and molding Presentation History commonly noticed once child begins walking parents report that the legs are "turning in" increased tripping and/or falling Symptoms usually asymptomatic Physical exam Rotational profile assessment foot progression angle hip internal rotation to identify increased femoral anteversion thigh foot angle to quantify tibial torsion heel bisector to identify metatarsus adductus Foot progression angle directed internal product of hip rotation, tibial torsion and shape of foot. measure angle between foot position and imaginary straight line while walking normal is -5 to +20 degrees thigh-foot angle directed internal technique prone position angle formed by a line bisecting the foot and line bisecting the thigh normal values infants- mean 5° internal (range, −30° to +20°) age 8 years- mean 10° external (range, −5° to +30°) thigh-foot angle > 10 degrees internal is generally considered as intoeing transmalleolar axis > 15 degrees internal technique measure the angle formed by an line from the lateral to the medial malleolus, and a second line from the lateral to the medial femoral condyles. normal average = 0 to -10 degrees internal rotation during infancy (which gradually laterally rotates to 15 degrees external rotation during growth) abnormal = greater than 15 degrees internal rotation Imaging Radiographs usually not indicated unless other conditions present (see above) Advanced imaging CT or MRI can be utlized for surgical planning (in the few cases that require surgery) Differential Causes of Intoeing Condition Key findings Metatarsus Adductus Medial deviation of the forefoot (abnormal heel bisector), normal hindfoot Tibial Torsion Thigh-foot angle > 10 degrees internal Femoral Anteversion Internal rotation >70 degrees and < 20 degrees of external rotation In-toeing associated with the following necessitates further work-up pain limb length discrepancy progressive deformity family history positive for rickets/skeletal dysplasias/mucopolysaccharidoses limb rotational profiles 2 standard deviations outside of normal Treatment Nonoperative observation and parental education indications most cases outcomes usually resolves spontaneously by age 4 bracing/orthotics do not change natural history of condition Operative derotational supramalleolar tibial osteotomy vs. proximal osteotomy indications rarely required child > 6-8 years of age with functional problems and thigh-foot angle >15 degrees technique associated with lower complications than proximal osteotomy fixaton with plate or smooth K wires intramedullary nail fixation if skeletally mature Prognosis Usually resolves spontaneously by age 4