Limb Differences (Limb Length Discrepancy)
Some babies and children have arms or legs of different lengths. This discrepancy may be present at birth or may occur later in life as the result of a bone break or an infection. Arm length discrepancies typically do not interfere with function or quality of life. However, leg length discrepancy (LLD) may cause a debilitating limp and require treatment.
Types
- Acquired. A baby or a child may develop LLD after a bone breaks in the leg or the limb becomes infected.
- Congenital. A shinbone that is missing or short at birth is called a fibular hemimelia. A thighbone missing or short at birth is called a focal femoral deficiency. Excessive growth on one side of the body is called hemihypertrophy.
- Idiopathic. A baby may have LLD for no apparent reason.
Symptoms
- Back pain
- Curvature in the back
- Difficulty walking
- Hip pain
- Tightness in the heel
- Walking on the toes
Prevention
- There is no way to prevent LLD.
Risk factors
- Bone diseases. Multiple hereditary exostoses, neurofibromatosis and Ollier disease may contribute to LLD.
- Bone infection. As the child grows, an infection may cause differences in the length of the legs.
- Bone injury. After a break, a child’s leg may grow more quickly as the bone heals. This may continue for years, resulting in a leg that is longer.
- Other existing health conditions. Inflammatory diseases like juvenile arthritis or neurological conditions may increase the likelihood of LLD.
Diagnosis
- Medical history and review of symptoms. The healthcare provider will ask the patents and child, if he or she is old enough, about physical function.
- Physical exam. The child’s doctor may observe the way the child sits, stands and walks. A limp or walking on the toes may indicate LLD. The doctor will measure the child’s legs and may have him or her stand on a block to see how dramatic the discrepancy is.
- Imaging. The doctor may order an X-ray to capture precise measurements of the LLD. A CT scanogram may also be recommended.
Treatment
- Conservative. A lift in the shoe may be used to manage mild LLD of about 2 centimeters or less.
- Epiphysiodesis. If the child is still growing, a surgeon may perform this outpatient procedure to compress the growth plate in your child’s leg.
- Surgical limb shortening. After the child has finished growing, a surgeon may shorten the longer leg by removing a portion of bone.
- Surgical limb lengthening. A surgeon may place an external fixator or a different device inside the bone to lengthen the leg. This option is usually recommended when the discrepancy is 5 centimeters or more.
Follow-up care
- After surgery, the child’s doctor will consult with the patient and his or her family regularly to closely observe bone alignment and quality.
- Gentle exercise and physical therapy will help build strength and stability.