What is a limb length discrepancy?

Limb length discrepancy most often refers to leg-length and when a child has one leg that is longer than the other. This is called leg length discrepancy (LLD) and it occurs when the femur (thigh bone), tibia, or fibula (shin bones), or all three, are shorter in one leg. Limb length correction may be needed if the limb length discrepancy is significant (more than 2 cm) and cause problems, such as pain, or an abnormal gait, and if the discrepancy continues to get worse as they grow.

What is limb length correction?

Limb length correction is a surgical procedure that treats a limb length discrepancy. There are different types of limb length correction, and the goal is one of the following:

  • Slow down or stop the grown of the longer limb
  • Shorten the longer limb
  • Lengthen the shorter limb

What are the different types of limb length correction?

The difference in the types of correction and when to perform the surgery varies greatly and should be based entirely on the specific child, their condition, rate of growth and intended outcome. The experts at BICMD can offer the second opinions through a telemedicine visit. Our “best-in-class” doctors have the most up-to-date information and techniques and can help you successfully navigate your child’s limb length correction. At BICMD we may suggest one of the following surgical corrective treatments:

Growth Plate Surgery – Epiphysiodesis

What is epiphysiodesis?

Epiphysiodesis is pronounced: ep-i-fiz-ee-uh-DEE-sis, and is the term used to describe a specific type of growth plate surgery. In medical terms the growth plate is called the physis. If one limb is significantly longer than the other, an epiphysiodesis surgically stops the growth of the limb, either temporarily or permanently. This is done in a simple outpatient surgery and one or two of the growth plates in the longer limb are compressed or scraped with a surgical plate and screws. The growth plate, found at the end of the bone where new growth occurs, is inhibited from signaling new growth and the longer leg stops or slows down until the shorter leg can catch up.

The timing for growth plate surgery is critical and our experts can guide you correctly. Epiphysiodesis can be extremely effective if the timing is perfect and if the procedure is done correctly. Disadvantages of growth plate surgery can include under or over correction and the child has the risk of a slightly shorter adult height.

Limb Shortening Surgery:

Limb shortening treatments are usually only recommended when the discrepancy is between 2 and 6 centimeters and when the child reaches maturity, or the end of bone growth. Shortening limb procedures are relatively safe and consist of a simple surgical procedure that removes a piece of bone in the longer limb. Metal plates and screws, or a rod is placed to hold the bone in place while it heals. Few complications result and healing is similar to a broken bone, where the new bone is stronger than before.

Limb Lengthening Surgery:

Limb lengthening can be done either externally or internally. Limb lengthening procedures are usually reserved for patients with significant discrepancies in length due to the complexity of the procedure.

External limb lengthening:

The goal of external limb lengthening is to use the body’s own capacity to regenerate new bone, soft tissue, ligaments, nerves and blood vessels. External limb lengthening begins with an operation called an osteotomy, where the skilled orthopedic surgeon cuts the bone to be lengthened (usually the upper leg, or femur or the lower leg or tibia) into two separate pieces. The cut bone is stabilized using a special external device that is affixed to the bone with wires, pins or both.

This scaffold-like frame is used after the surgery as part-two of the lengthening process. Approximately 5 to 10 days after surgery, the dial on the frame, or fixator, is turned several times each day. The bones very slowly and gently pull apart (this is called distracted) and the body creates new bone growth in the space. The muscles, skin and other soft tissues adapt as the limb slowly lengthens. The process is slow, just 1 millimeter a day. In one month, the bone will grow as much as 1 inch.

The external fixator is worn until the bone has reached the desired length and until the bone is strong enough to support the patient. The average time for a healthy patient to complete external leg lengthening is about three months. The hardware is then surgically removed in a simple outpatient procedure.

Internal Limb Lengthening:

The process for internal limb lengthening is, in concept, the same as the external limb lengthening, but accomplished inside the limb, without the external fixator.

During the first phase, the orthopedic surgeon cuts the bone of the shorter limb into two segments. A metal rod is implanted into the bone which has the capability of lengthening in response to the normal movements of the patient’s limb. The second phase occurs when the rod slowly lengthens and the bones are pulled apart to allow new bone growth in the space created. The internal rod provides stability and alignment as the bone lengthens.

Over time, when the bone has reached the desired length and is strong enough to hold a patient’s weight safely, the internal rod can be removed through an outpatient procedure, similar to removing the external fixator device.

There are pros and cons for each type of limb lengthening and both should be discussed with one of our experts at BICMD. They can explain the best option for limb length correction and your child’s specific needs.

For more information and resources on limb length correction and growth plate surgeries, or to obtain an expert 2nd opinion before having a surgical procedure, please contact our orthopedic specialists, by clicking on “Connect With a Doctor.” You will be connected to one of our orthopedic telemedicine experts through our state-of-the-art telemedicine platform.