Femoral Anteversion (Squinting Patella), Internal Tibial Torsion, and Metatarsus Adductus
Medical InBrief
Intoeing is observed in many toddlers. It refers to a child’s feet pointing inward while standing, walking or running. Some people refer to intoeing as “pigeon-toed.”
Intoeing cosmetically appears worst shortly after the child begins walking. Intoeing may be measured as the “foot progression angle,” which is the angle the plantigrade foot makes relative to the line of gait progression on the floor. The internal rotation seen in the infant and toddler is almost always bony in etiology rather than simply positional. The intoeing is a residual finding due to intra-uterine molding of the various structures in the fetus’ lower extremities. The deformities that contribute to intoeing can be divided into those occurring in the femur, the tibia, the foot or combinations of these structures. Less commonly intoeing can be due to internal rotation contracture of the hip. This discussion does not include intoeing developing in the older child due to neuromuscular disorders such as cerebral palsy, particularly spastic diplegia.
Femoral Anteversion
Normally, during development of the fetus there is an inward rotation of the femur as it progresses from the hip to the knee; this rotation is referred to as femoral anteversion, or the anteversion angle. In the full term baby, femoral anteversion usually measures less than 40 degrees. However, some infants are born with excessive femoral anteversion that may measure in excess of 60 degrees. The increased femoral anteversion presents clinically as intoeing when the baby begins to walk, due to inward rotation of the entire lower extremity. When the infant with increased femoral anteversion is examined the baby is found to have an increased range of internal rotation at the hip with a corresponding decrease in external rotation. In the toddler with femoral anteversion, when walking not only are the toes observed to be internally rotated but the patella is also seen to be medially pointing, suggesting a more proximal etiology of the intoeing. The observed medially pointed patellae are referred to by some as “squinting patella.”
Mild to moderate femoral anteversion of 20 to 40 degrees has little encumbrance to the child and can be treated with observation. More severe forms of excessive femoral anteversion, with angles greater than 45 degrees, may have a subtle adverse affect on the child while running, by limiting pelvic rotation during the stride, additionally there is evidence that severe femoral anteversion may contribute to developmental hip dysplasia. Radiographs or other imaging modalities may be indicated to follow the development of the growing pediatric hip in cases of severe femoral anteversion.
During growth, children with femoral anteversion may develop varying degrees of compensatory external tibial torsion. Tibial torsion refers to the twist of the tibia as it progresses from the knee to the ankle. Compensatory external tibial torsion has the effect of correcting the foot progression angle toward neutral. However, medial rotation of the patellae persists, and encumbrance of running persists. The natural history of femoral anteversion is that it usually tends to somewhat decrease in magnitude throughout the growing years with greatest correction in the first decade of life. It is believed by some that certain activities over time may affect femoral anteversion. Persistent sitting of the toddler in the “reverse tailor” also called the “W” sitting position may contribute to femoral anteversion and should be discouraged.
Internal Tibial Torsion
Another common cause for intoeing in toddlers is internal tibial torsion. Similar to femoral anteversion, internal tibial torsion is a medial rotation of the tibia as it progresses from the knee to the ankle. It is measured by comparing the axis of the tibial condyles to the axis of the medial and lateral malleoli. Internal tibial torsion can appear quite severe and may contribute to children tripping over their own feet. There is also thought to be a complex relationship between internal tibial torsion, early walking, obesity and infantile tibia vara (Blount’s disease). Most significantly, internal tibial torsion (ITT), even fairly severe internal tibial torsion, tends to spontaneously improve. Braces to correct internal tibial torsion, such as “twisters” are not effective and may be harmful to the ligaments of the developing knee joint. In the uncommon child when ITT does not spontaneously correct, and the child has a resulting disability surgical solutions exist to provide excellent results.
Metatarsus Adductus (MA)
The final cause of intoeing in the toddler is due to a foot deformity known as metatarsus adductus (MA). In non-syndromatic cases of MA the precise etiology is unknown but thought to be a modeling phenomena due to the fetal foot pressing against the uterine wall creating a bean shaped deformity of the foot. Metatarsus adductus is a significant finding, and almost always requires treatment. Treatment may consist of serial casting of the affected foot or feet, stretching exercises, and special foot-wear. In rare cases of MA, surgical intervention is necessary to obtain a satisfactory result.
Metatarsus adductus results in shortening of the longitudinal plantar arch resulting in anon-neuromuscular cavus-like deformity of the foot that alters the weight bearing on the plantar surface of the foot. In adulthood the change in shape of the foot leads to difficulty in properly fitting shoes, increased weight bearing on certain parts of the foot causing pain, calluses and even skin breakdown. Metatarsus adductus is different from a clubfoot in which the primary deformity is in the hind foot while in MA the deformity is in the forefoot.
Occasionally mild forms of MA may resolve spontaneously but, in general metatarsus adductus should be treated immediately upon discovery, early in life. Lengthy periods of observation that delay treatment will ultimately make treatment more difficult and the ultimate result less satisfactory.
Conclusion
Femoral Anteversion (aka Squinting Patella), Internal Tibial Torsion and Metatarsus Adductus.
It is not uncommon to find combinations of these three causes for intoeing to occur in a toddler. Examination and evaluation by an experienced pediatric orthopaedic surgeon can help determine the cause of the intoeing and, if necessary, institute proper treatment in a timely manner.
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