What is Fibular Hemimelia?
Fibular hemimelia is a rare birth defect affecting the lower limbs, particularly beneath the knee. In this condition, the child is born with a shorter than normal or missing fibula (calf bone). This makes one leg shorter than the other. It may affect one (usually the right one) or both legs.
What are the Causes of Fibular Hemimelia?
The exact cause of fibular hemimelia is not clear. However, it may occur due to:
- A mutation in the genes
- Problems during fetal development
- A deviation from the normal head-down position of the fetus in the uterus such as breech or transverse position
- Childhood trauma or fracture
What are the Signs and Symptoms of Fibular Hemimelia?
Some of the common signs and symptoms of fibular hemimelia may include:
- Limb length discrepancy: one leg shorter than the other or unable to touch the ground
- Knee deformity
- Abnormal gait (walking style)
- Foot and ankle deformity
- Tripping during walking or running activities
- Pain in the hips and/or knees
How is Fibular Hemimelia Diagnosed?
You should consult an orthopedic surgeon specializing in knee, hip or foot and ankle disorders. The doctor will review your child’s medical history, family history, and check for external symptoms such as bone deformity and abnormal gait. In addition, strength of the muscles in the lower limbs and range of motion will also be checked. Imaging tests such as X-ray, MRI (magnetic resonance imaging) or a CT (contrast tomography) scan may also be recommended to confirm the diagnosis and develop a treatment plan best suited for your child.
What are the Treatment Options for Fibular Hemimelia?
Treatment for fibular hemimelia requires a multidisciplinary approach which includes a combination of conservative management and surgical treatment. The first choice of treatment is usually non-surgical. It is only after the condition doesn’t resolve on its own or failure of non-surgical methods, that the doctor will suggest surgery.
Non-Surgical Treatments
- Oral medications such as nonsteroidal anti-inflammatory drugs (NSAIDs) to suppress pain and inflammation
- Orthotic devices such as insoles, knee braces, and crutches to provide walking support
- Physical therapy in the form of massage and exercises
- Pain relief injections into the affected joint to suppress the pain and inflammation
- Immobilization by a cast or splint to allow the affected leg to rest
Surgical Treatment
Surgery is recommended for severe fibular hemimelia and those cases which fail to heal despite conservative therapy. The surgical procedures for fibular hemimelia may include:
- Guided growth surgery
- Limb lengthening
- Amputation of the limb
Guided Growth Surgery
Guided growth surgery also known as hemiepiphysiodesis is a minimally invasive surgical procedure in which a small plate called a guided growth plate or tension band plate is inserted into the leg bone to correct limb deformity such as bow legs or knock knees. It is fixed to the bone across the growth plate and guides bone growth to correct the deformity.
Limb Lengthening
Limb lengthening is a reconstructive procedure that involves the following:
- Combination of reconstruction procedures to repair the deformed/missing bones and muscles followed by,
- Gradual lengthening of the leg using an external fixator.
- The external fixator is worn until the lengthened bone becomes strong enough to support the patient to stand on their own.
The process of increase in bone length depends on tissue and bone regeneration. When the bone is pulled apart, it regenerates at the rate of approximately 1 mm per day.
Limb lengthening usually requires multiple operations over several years to help restore the leg to normal.
Limb Amputation
Limb amputation is performed under general anesthesia. It involves removal of the affected limb or a part of the limb based on the extent of damage. The surrounding tissues and muscles which are damaged are also excised (cut and removed). The healthy tissues and areas of healthy bone are smoothed out, blood vessels and nerves are sealed, and the muscles are shaped to facilitate the addition of artificial limbs if applicable.
