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Conditions

Leg Length Discrepancy

Overview

Child with external fixator
Child with external fixator for lengthening the left femur.

Causes

There are many causes of LLD. These include birth conditions such hemihypertrophy, proximal focal femoral deficiency, and skeletal dysplasias.  They can include nerve problems such as polio or cerebral palsy.  There can also be problems from trauma, infection or tumor affecting a normal growth plate.
 

Associated problems

With a large LLD, patients may experience back pain or hip pain.  There may be a curve in the back.  A limb length discrepancy may lead to walking problems or toe walking.  The heel cord may become tight from toe walking.
 

Evaluation

The doctor will examine a child with LLD to estimate the difference and for tight tendons.  It’s common to have the child stand with the shorter leg on a block for the exam.  X-rays or CT scans may be used to measure the difference.  The doctor can calculate how much of a difference there will be when your child is an adult.  Treatment will be planned based on that difference.  It is assumed that girls will stop growing when they are around 14 years old and boys will stop growing when they are around 16 years old. 
 

Treatment

Non-Operative

For mild LLD (usually less than 2 centimeters), a shoe lift may be used.  If the patient is comfortable, the plan may be to watch for changes.
Leg length discrepancy xray
X-ray of child with limb length discrepancy standing on a block.

Operative

If the doctor expects the difference in limb lengths to be greater than 2 centimeters, surgery may be recommended.
If the difference is expected to be between 2 and 5 centimeters when your child is done growing, the growth on the long leg can be slowed down so that the shorter leg catches up.  This is done with a surgery to stop growth at the growth plate or by placing surgical plates over the growth plates to slow the growth down.  Either of these options is an outpatient procedure.

If the difference is expected to be over 5 centimeters, the shorter side can be lengthened.  This is a much bigger surgery that involves cutting the bone on the short side and using a device to slowly lengthen it. This can be done with a device on the outside of the leg (as shown) or with an implant inside the leg.   This process may take months, but patients will be able to walk and go to school for much of the treatment.
 
 

More Information

Q. Will this affect my child’s ability to play sports?

Most children and teenagers heal very well after this injury. They should be able to return to their previous level of sports and activities.
 

Q. Will the pins or metal implants stay in permanently?

The implants used in surgery are nails (rods), screws and plates.  These implants may have to be removed, depending on the age of the child and other factors. You and your doctor will make the decision for implant removal together.  If recommended, the implants may be removed once the fracture is fully healed, usually within 6 to 12 months after injury.
 

Q. How long will the recovery be?

Your doctor will restrict activities such as sports or gym at least until the fracture is healed. The bone could break again if you return sooner than recommended. Femur fractures commonly require several months to heal. This depends on the type of fracture and how the healing looks on the x-ray.
 

Q. Will my child need physical therapy?

Most children do their own therapy through play.  Formal physical therapy is usually not required after this injury.
 

Q.  How will I know if my child’s leg is growing at an angle, or is longer or shorter than the other leg?

This is commonly noted after a broken femur and usually does not need treatment. After the fracture is healed, your doctor will let you know you should be seen regularly.  If necessary, your doctor will keep observe your child over time to check for these problems.  If the leg does grow in an angle or if there is a difference in leg lengths as a result of a femur fracture, there are surgeries that can be done to address these problems.