Leg Length Discrepancy

Leg length discrepancy (LLD) is a condition in which the legs are not the same length. While small differences don't typically cause problems, larger differences in length can affect walking, posture, and cause pain over time. There are both nonsurgical and surgical treatments that can help correct this condition.

What Causes LLD?

The majority of people in the world (about 2/3 of the general population) have some degree of leg length discrepancy from 0 cm up to 1.5 cm (1/2 inch) of difference. Changes in walking mechanics and pain symptoms generally do not begin until LLD exceeds 2 cm (3/4 inch). Above 3 cm (over 1 inch), the effect becomes extremely noticeable. An LLD can be caused by:

• Birth differences in bone growth
• Past injuries that affected growth plates
• Bone infections near growth plates
• Conditions like Blount's disease or cerebral palsy
• Tumors or certain genetic conditions

LLD can be present at birth or develop over time. When the exact cause isn't known, it's known as idiopathic LLD.

What Are the Symptoms?

You may notice signs such as:

• A visible difference in leg length
• Limping or walking on tiptoe
• Uneven hips or shoulders
• Back, hip, knee, or ankle pain
• Trouble running or playing sports

When Should My Child See a Doctor?

Your child should see a specialist if:

• You notice your child limping often or favoring one leg
• Your child complains of joint or back pain
• Your pediatrician notices uneven leg lengths during a checkup

How Is This Condition Diagnosed?

Doctors use several tools to confirm a diagnosis:

• A physical exam to measure the legs
• X-rays to check bone growth and structure
• CT scan or MRI for more detailed imaging
• A leg length scanogram (a special X-ray to measure bones precisely)

How Is This Condition Treated?

Treatment depends on the size of the difference and how much more growing your child has left to do. The goal is to help your child walk normally, stay active, and prevent long-term joint issues.

Nonsurgical Options:

For small differences (usually under 2 cm), your doctor may recommend:

• Observation
• Shoe lifts or inserts to even out leg length
• Physical therapy to strengthen muscles and improve posture
• Regular monitoring to track growth

Surgical Options:

If nonsurgical treatment doesn't help, or if the LLD is severe, surgery may be necessary. The goal of LLD surgery is to make the two legs as equal as possible. General approaches include:

• Modulating the growth of the longer leg in skeletally immature patients
• Acutely shortening the longer leg in skeletally mature patients, or
• Lengthening the shorter leg

Procedures include:

• Epiphysiodesis or “guided growth”: A minimally invasive procedure that targets the growth plate to slow growth in the longer leg
• Leg lengthening surgery: The shorter leg is gradually lengthened using a special device, which is sometimes implanted in the leg or attached externally. In both cases, these devices are later removed.
• Leg shortening surgery: A small section of bone is removed from the longer leg after the growth phase is complete. An internal device is utilized to hold the bone together and does not need to be removed.

What Are the Risks for Surgery?

Surgery is generally safe, but as with any procedure, there are some risks:

• Infection
• Blood clots
• Delayed bone healing
• Pain or stiffness
• Differences in bone growth

Your child's surgeon will explain the risks and how they are managed.

What Does Recovery from Surgery Involve?

Recovery depends on the type of surgery. Typically, recovery from LLD surgery includes:

• Possible hospital stay for more invasive procedures
• Pain management
• Physical therapy
• Crutches or a walker for a few weeks
• Regular follow-up appointments and imaging

How Long Does Recovery Take?

Healing from epiphysiodesis usually takes a few weeks, but full recovery from leg lengthening surgery can take up to a year. Physical therapy is critical to the success of any leg-length discrepancy surgery.

What Is the Outlook for LLD?

With proper treatment, most children with leg length discrepancy do very well. Most children with LLD do not require any treatment as the body tolerates differences of up to 1.5 cm. Regular checkups with an orthopedic specialist will help track growth and guide treatment as needed. Whether your child needs an orthopedic device like a shoe insert or surgery, the goal of treatment is to help them walk evenly and stay mobile and pain-free.