CFD occurs in about one in forty-thousand births. The cause is generally unknown. CFD presents along a spectrum of deficiency and deformity, ranging from relatively minor to severe cases. Treatment strategies for CFD depend on the severity. In all but the most extreme cases, deformity correction surgery and limb lengthening is the preferred treatment method.
The cause of an isolated single-limb abnormality is generally unknown. CFD is usually not associated with a genetic abnormality unless multiple limb deficiencies or other congenital abnormalities are present. Exposure to certain drugs and chemicals, radiation, and viruses are known to cause limb deficiency (e.g. thalidomide). Barring such exposure or a family history of congenital limb or organ abnormalities, CFD is almost always a non-hereditary condition. CFD is sometimes associated with Fibular Hemimelia.
Congenital femoral deficiency is characterized by a progressive limb length discrepancy. The affected limb does not grow properly, so as the patient ages, the discrepancy between the two limbs will continue to increase. As the expected discrepancy at skeletal maturity increases, the number of lengthenings required to equalize length will increase.
There is generally no rush to treat CFD. Dr. Paley will usually perform the first surgery around age two or three. Prior to surgery, shoe lifts, orthoses (braces), and prostheses can all be used to manage the limb length discrepancy. All children with a limb length discrepancy (LLD) of greater than 2 cm should use a shoe lift when they begin to walk. When the LLD is greater than 5 cm, an articulated ankle-foot orthosis (AFO) may be useful to provide ankle support. If the lift is greater than 10 cm, a prosthetic foot connected to an articulated AFO may be preferred because of aesthetic considerations—a prosthetic foot allows wearing two shoes of the same size and style with no shoe lift beneath the shoe.
Congenital femoral deficiency is very rare and its treatment relatively new. For this reason, few surgeons are experienced and trained to treat CFD. Surgical treatment should preferably be carried out at specialized centers with surgeons who see and treat many patients with these conditions and at centers who have dedicated rehabilitation programs for limb lengthening patients. The Paley Advanced Limb Lengthening Institute is the most experienced such center in the United States and the world, having performed over 17,000 lengthening surgeries, of which more than 1000 were for congenital femoral deficiency.
