Femoral anteversion refers to medial torsion of the femur, which is a normal variant in most children, but may be excessive in a small minority. In this minority it leads to in-toeing of the feet and a clumsy gait while walking or running. The physician then has several therapeutic possibilities. A decision is made based upon the child’s age, previous and current medical history, health status and the problem posed by the torsion.
Most children with femoral anteversion show complete correction over the course of years. By the age of 10 years, 80% of them start to walk normally, with the torsion reduced to near normal degrees. More correction occurs during adolescence as they consciously turn their feet outwards and this leads to the condition disappearing during this period in almost 99% of affected children.
For this reason, close observation is sufficient until the age of 8 years in the majority of cases. The range of motion at the hip joint is measured every six months, or at one year intervals, to record the reduction in the anteversion over time. It is established that the wearing of braces, special shoes or exercises have no role to play in hastening this process, which is brought about largely by the body’s own corrective mechanisms. Mild degrees of anteversion without cosmetic or functional impairment do not need to be corrected as they are not associated with any long-term consequences like arthritis.
During the period of self-correction, children tend to sit in the typical W position with the legs bent backwards and out at the knees. This neither causes nor aggravates the condition, but it is comfortable for the child, because of the inward rotation of the hip joint. Thus, parents may allow their children to sit as they please without fear until the anteversion is corrected on its own.
When the condition is of sufficient severity to cause an apparent deformity or functional disability, with objective measures of excessive torsion, surgical treatment is recommended in some cases. Even then, most adolescents with excessive anteversion do not experience any difficulty in gait, whether walking or running, nor do they have any pain. The following conditions are usually taken into account before surgery is considered:
- The child is over 8 years of age and the anteversion has not shown improvement
- The child is less than 8 years, but the in-toeing gait makes it impossible to walk properly
- The condition is severe, with over 50 degrees of anteversion and over 80 degrees of torsion
- The child has an apparent deformity more than 3 standard deviations above the mean
- The child has a serious functional disability, being unable to walk and run without frequently tripping and falling
- The condition is painful
- The family realizes the potential complications of the surgery
The procedure most often resorted to is called a femoral de-rotation osteotomy. The femur is cut through, the ball of the femur is rotated until the anteversion is corrected, and the rest of the bone is reattached using a plate and screws. Groin muscles, which hold the femur in anteversion, must also be lengthened at the same time to allow the femoral head to fix itself into the new position. The goal of the procedure is for the toes to point forward.
Recovery following this procedure usually includes hospitalization for a couple of days. Assisted walking will usually begin before discharge with the help of a physical therapist. The use of a cast is uncommon, and usually soft bandages are applied. Pain relievers will be required. Assistance may be required for activities that involve hip movement.
Physical therapy will help in regaining lost muscle strength. Weight-bearing is not allowed for a month or two, until bone union has begun. Following this, the child is encouraged to ambulate with the help of crutches or a walker. Most children may be back to their full range of activity within four months. Since this procedure is usually performed during childhood, the prognosis is excellent and better than what is seen if it is done later in life.
Complications are relatively rare, but may include infection, hemorrhage, fractures, and malunion. These are usually easily treated. The plate is removed only if there are any symptoms related to its presence, which is rare. This may occur if the child is very slim. It is a minor procedure in most cases. A repeat correction may be needed in some cases when the surgery is done while the child is still young, to enable the child to walk. The repeat surgery is due to the recurrence of the anteversion.
Reviewed by Jonas Wilson, Ing. Med.