Congenital Femoral Deficiency

Congenital femoral deficiency (CFD) is a rare birth defect characterized by hip and knee deformity, instability, and deficiency. The affected thigh could be shorter and more crooked than the other normal leg. This deficiency appears with fibular hemimelia in which the fibula is absent or short, along with a short tibia.

The cause of congenital femoral deficiency is unknown and occurs in at least one out of forty thousand births. 

It is also referred to as Proximal Femoral Focal Deficiency (PFFD). Congenital femoral deficiency (CFD) presents a range of minor to major deformities and deficiencies. Most orthopedic doctors suggest deformity correction surgery and limb lengthening to resolve the issue. 

Causes of Congenital femoral deficiency (CFD)

The cause of congenital femoral deficiency is still unknown. However, research states that it is caused due to disruption during early prenatal development or an outcome of an external condition, e.g., a trauma or infection. Also, research has revealed that consumption of the drug thalidomide during pregnancy can cause femoral and other limb deficiencies.

Also, exposure to select chemicals, drugs, radiation, and viruses can cause femoral deficiency, while no specific disorder has been identified with congenital femoral deficiency.

Symptoms of Congenital femoral deficiency

The symptoms vary from patient to patient while the femur is short, rotated externally, flexed, and abducted. In addition, the patient can have an unstable or absent hip joint on the affected leg and/or an unstable knee joint.

Additionally, if congenital femoral deficiency is present with other abnormalities, then the patient can have 

• Short or absent fibula in the lower leg
• Valgus foot or flat foot
• Club foot
• Congenital heart defects
• Cleft palate

The affected limb does not grow properly, and the discrepancy in limb length increases over time.  Hence, the number of corrective limb lengthening procedures required to equalize the length will also increase. 

The patient is identified with congenital femoral deficiency only if multiple limb deficiencies or other congenital abnormalities are evident. Also, the cause of an isolated single-limb abnormality is not known. Nearly 85% of patients with congenital femoral deficiency have their one leg affected, while the remaining have both legs affected.

Diagnosis of congenital femoral deficiency

Congenital femoral deficiency condition is identified at birth or during prenatal imaging. The femur will appear short, externally rotated, abducted, and flexed. The clinical examination involves a physical examination accompanied by complete medical history to understand the patient’s anatomy, severity or extent of deformity, and functionality. 

In many cases, doctors will order imaging tests such as x-rays, EOS imaging, CT scan, MRI, 

Hip arthrography and ultrasound to ascertain the extent of deficiency and suggest a treatment plan. 

Treatment of congenital femoral deficiency

The congenital femoral deficiency is likely to be a lengthy and comprehensive one that requires a great deal of planning, while the key factors that determine the approach are 

• The severity of the child’s deformity
• The functional and psychological outcomes of the patients
• The recovery expectations of the family  

Non-Operation Treatment includes 

• Observation

• Bracing – To establish stable weight-bearing extremity

• Use of prosthesis

The surgeon would like to wait for the child to grow older till they are fit for surgery or in-between periods during the surgical treatment. All patients with this deficiency will need a customized plan that includes orthotic and surgical treatment. If possible, the orthopaedic surgeon could recommend complex reconstruction and limb-lengthening up to 25-30 cm for patients with reconstructable hip and knee joints.

Surgeries for Congenital Femoral Deficiency

Limb modification is considered in patients with severe deformity using foot ablation, knee and/or hip arthrodesis, or rotationplasty. The treatment focuses on correcting the deformity of the hip and/or knee joint and then proceeding for limb lengthening.

Before suggesting a limb-lengthening procedure, the doctor will pay attention to the expected limb-length discrepancy and whether the hip and knee joints are stable or reconstructable.  

However, a limb modification plan will include arthrodeses, partial amputations, and rotationplasty, along with the use of orthotics in the future. 

Limb lengthening procedures

After the patient has recovered from the hip and/or knee reconstruction surgeries, the orthopedic surgeon will plan the limb lengthening phase, which works with the growth of the new bone. The orthopedic surgeon will perform an osteotomy to insert the external fixator across the knee joint, while the pins are placed in the tibia which will help to lengthen the limb.

The patients and parents are instructed on using the fixator for lengthening the bone. The regeneration process of the bone is extremely slow i.e. approx 1 mm per day. This phase is also known as the distraction phase. 

The patients have to undergo extensive physical and rehabilitation therapy under medical and parental supervision to ensure a successful lengthening outcome.

After the distraction phase, the patient enters the consolidation phase, wherein no adjustments are made to the external fixator. Finally, the external fixator is removed after the new bone has hardened. 

Summing it up, limb lengthening is a very complicated and complex process. The treating orthopedic surgeon and team, the patient, and the patient’s family need to cooperate. The treatment of congenital femoral deficiency is meticulous as it is a combination of surgical and non-surgical techniques that need vigilant follow-up and persevered rehabilitation for its successful outcome.  

Dr. Ratnav Ratan, one of the leading pediatric orthopedic surgeons in Delhi and Gurgaon, states that congenital femoral deficiency is rare while its treatment is still evolving. Hence, choosing an expert and trained pediatric orthopedic is very crucial who has successfully handled cases of congenital femoral deficiency.