What does it mean to have a limb length discrepancy?
A limb length discrepancy simply means there is a different size in the length of the arms or the legs. In children, parents may notice a leg length discrepancy as they grow. Limb length discrepancies are not uncommon, nearly one-third of the population may have a difference of 1 cm or less in their right and left legs. A difference this small is not noticeable and doesn’t usually require any kind of treatment. Differences in arm length are often less noticeable and do not usually impact the function of the arms or hands.
Large limb length discrepancies may have a significant impact on how a child moves. Some children develop a noticeable limp, have difficulty walking or running and experience back or hip pain. Other children may not be able to perform daily activities if the limb length discrepancy is considerable. In the cases of a larger limb length discrepancy, it is important to seek an expert consultation. The doctors and specialists at BICMD are “best in class” in their field and can give you the best treatment advice during a telemedicine visit, done through our state-of-the-art telehealth platform.
What causes a difference in limb length?
Most children with significant limb length discrepancies are born with the condition. When the child begins to crawl or walk, the limb length difference becomes obvious. There are many other causes of limb length discrepancy, those can include:
- Previous injury or trauma to the bone
- Compound fractures
- Fractures near or involving the physis (growth plate)
- Bone infection
- Bone dysplasias (bone diseases)
- Ollier disease
- Multiple enchondromas (benign tumors in the bone where the bone marrow is stored)
- Multiple exostoses (benign growths of bone)
- Neurofibromatosis (hereditary condition that makes one susceptible to growing tumors)
- Neurological conditions
- Cerebral palsy
- Congenital Conditions
- Developmental dysplasia
- Hemihyperplasia or hemihypertrophy
- Juvenile arthritis
What are the symptoms of limb length discrepancies?
The symptoms of limb length discrepancies will vary based on the severity of the length difference as well as the cause. Symptoms are also more evident when the legs are in discrepancy and may include:
- Walking on the tip-toes of one foot (compensating for difference in length)
- Hip or leg pain
- Child is easily fatigued from walking or moving
- Uneven size of the femur (thigh bone) or the tibia (shin bone)
- Uneven size of the fibula (small bone in the lower leg)
How is a limb length discrepancy diagnosed?
Parents are often the first to suspect a limb length discrepancy. They may notice the child is limping or has an abnormal gait. Limb length discrepancies are also often found by school nurses during scoliosis screening. A doctor’s exam should follow these early discoveries and will include a physical exam. This initial exam may include a measurement of the length difference, using blocks under one foot until the hips are level. Diagnostic imaging may be required and can include x-rays, CT scan, MRI scan, Scanogram or EOS imaging which creates a 3-D model from 2 flat images.
It is not unusual for a doctor to repeat the physical exam and imaging studies every six months to a year to determine if the limb length discrepancy has increased, decreased or stayed the same.
What is the treatment for a limb length discrepancy?
For mild limb length discrepancies, which are classified as less than 2 centimeters, a simple shoe lift may be used. Observation will also be needed and treatment may be adjusted based on the severity of the discrepancy. Surgery is not often recommended until children reach skeletal maturity which is on average 14 for girls and 16 for boys.
Surgical treatment for a limb length discrepancy may be suggested if the length difference is more than 2 centimeters, or if the expected difference is anticipated to be greater than 2 centimeters when the child is done growing. There are different goals for surgical treatment designed to do the following:
- Slow down or stop the growth of the longer limb
- Shorten the longer limb
- Lengthen the shorter limb
Surgical treatments or procedures for limb length discrepancies should be carefully considered. The experts at BICMD can give you a second opinion and will explain the best treatments for your child’s specific limb length discrepancy. Suggested surgical treatment may include:
- Epiphysiodesis – Slow down or stop growth at one or two growth plates in the longer leg
- Limb shortening – Removes a section of bone in the longer bone
- Limb lengthening
- External lengthening
- Internal lengthening
Read more about Limb Length Correction and Growth Plate Surgeries
For more information and resources on limb length discrepancies, 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.