Femoral anteversion is a condition in which the thigh bone or femur is twisted inwardly, resulting in the in-turning of the knees and feet. The gait is typically pigeon-toed.
The stance of the affected toddler or child shows a bowed-leg appearance, because of the position of the femur. However, this actually improves the balance of the child. On the other hand, holding a position with the feet together or turned out can cause the child to become unsteady and fall more often.
The condition first manifests between the ages of 2-4 years, which is when the hip is maximally rotated medially. It is best seen outwardly at the age of 5-6 years. Femoral anteversion with about 30 to 40 degrees of torsion, present at birth, is considered a normal variant. This decreases over the childhood years to a low of 15 degrees by the time of completed bone growth.
Excessive medial torsion of the femur can cause in-toeing from early childhood onwards, and is present in about 10% of children. It is twice as common in girls and usually affects both femora. There is a strong familial link, with the mothers also having the same type of intoed gait. The result of this gait may be teasing for clumsiness, because of the increased tendency to trip or fall, and the awkward pattern of walking and running. The cause for excessive femoral anteversion is still unknown, and most patients have no other abnormality.
Signs and Symptoms
The following clinical features indicate the presence of femoral anteversion:
- Pigeon-toe gait with the toes pointing inward
- The child cannot keep the feet together with the legs straight
- Legs swing out while running
- Clumsy walk and run with frequent tripping or falling
- Typical W-shaped position while sitting with the knees bent and the legs out to each side behind the child
Almost all children (99%) with this condition require no treatment. It resolves by reduction in the degree of medial rotation by the age of 10 years in at least 80% of children. Furthermore, the prevalence is further reduced by conscious correction of gait and stance by the time they are adolescents.
Surgical correction is recommended only under the following conditions:
- In-toeing after the age of 8 years
- Severe anteversion causing a noticeable deformity and functional disability
- Anteversion over 50 degrees or deformity that is severe enough to be over 3 standard deviations beyond the mean
Surgery for this condition rarely results in complications, which mostly comprise of hemorrhage, malunion or infection. The outcome is generally good.