Ninety percent of the population has some leg-length discrepancy. At first glance, a slightly shorter leg is no big deal. After all, nobody measures the length of their legs — that is, until the pain in their knee, hip, or lower back brings them to a doctor. Doctors find that about 75 percent of low back pain patients have a different leg length and 84 percent of hip replacement patients have osteoarthritis in the longer limb.
Leg length discrepancy can be functional or anatomical.
If you have anatomical leg length discrepancy, you should discuss it with an orthopedic doctor.
Functional leg length difference is caused by muscle imbalances. This is associated with crooked posture and pelvic obliquity while sitting, standing, walking, or playing sports. You can address these muscle imbalances with the appropriate exercises.
Since the Middle Ages, leg length discrepancy has been treated with a shoe lift. But there is no way to fix core muscle imbalance with a shoe lift alone. You also need to perform regular corrective exercises.
Having one leg longer than the other is relatively common. The condition is known as leg length discrepancy.
Some research indicates that 40–70% of people have some form of leg length discrepancy (LLD).
The differences in leg length can range from a fraction of an inch to several inches. The greater the difference, the more likely it is that the person will experience issues with gait, posture, and pain.
In this article, we discuss the causes and symptoms of LLD. We also provide information on the diagnosis of LLD and the treatment options available.
There are two types of LLD: functional and structural. These types have different causes.
Functional LLD
In functional LLD, the leg bones are equal in length. However, one leg appears longer than the other due to an issue with one of the following body parts:
In children, functional LLD can occur when a child is born with an issue that alters their hip alignment.
In adults, functional LLD can result from chronic pain or arthritis and associated problems in the spine, hip, or knee.
Neuromuscular conditions are another potential cause of functional LLD, as these conditions can affect a person’s alignment and posture.
In some cases, exercise can contribute to functional LLD. If an athlete trains in a way that causes muscle imbalances or weaknesses, they may temporarily experience functional LLD.
Structural discrepancy
Structural LLD occurs when either the thigh bone (femur) or the shin bone (tibia) is shorter in one leg than in the other. The condition typically presents at birth, but it can also happen as a child grows.
Some potential causes of structural LLD include:
- Bone injuries: Bone breaks can slow down bone growth in one leg. This effect is especially likely if the break caused the bone to shatter into many pieces or injured the surrounding muscle tissue. Occasionally, a fracture that is healing may trigger an overgrowth of bone tissue. This overgrowth is most common in young children who have femur fractures.
- Growth plate injuries: Growth plates are areas of cartilage that sit near the end of the long bones. Sometimes, a growth plate can sustain an injury, which may cause the bone to grow faster or slower than the bone on the opposite side of the body.
- Bone diseases: Bone diseases such as osteomyelitis can cause damage to the bone’s growth plate. This damage eventually leads to LLD.
- Bone tumors: Bone tumors and their treatments can affect bone growth and contribute to LLD.
- Juvenile arthritis (JA): JA is a childhood autoimmune disease that causes inflammation of the tissue inside the joints. It can cause discrepancies in bone growth.
The main symptom of LLD is having one leg longer than the other. If the discrepancy is very small, there may not be any other symptoms.
However, a 2017 study notes that a discrepancy as small as 2 centimeters (cm) can cause the pelvis to compensate for imbalances in posture.
Moderate-to-severe cases of LLD can cause additional symptoms, including:
- gait issues, such as a limp
- pain in the back, hip, knee, or ankle
- increased tiredness
The study authors also note that LLD can affect a person’s overall quality of life.
People who suspect that they have one leg longer than the other should see a doctor for a diagnosis.
While waiting for an appointment, a person could try the following home test to see whether there is a possibility of LLD.
Home test
To perform a home test, the person should:
- Remove their shoes and socks.
- Lie down on the floor, keeping the legs together.
- Ask a friend or family member to place the palms of their hands on the person’s hip bones, so that they have one hand on each hip.
- Ask the helper to move the person’s hips gently from side to side for approximately 60 seconds. This motion helps loosen up tight muscles.
- Ask the helper to check the alignment of the person’s ankle bones.
Ankles that are not aligned could indicate LLD. It will be necessary to see a doctor to confirm LLD and to determine whether it is a functional or structural issue.
Medical diagnosis
A doctor may use several methods to diagnose LLD. These include:
- physical examination
- observation of how the person stands, sits, and moves
- gait analysis
- measuring the LLD by asking the person to stand on blocks of various heights until the hips are level
- X-ray of the pelvis or legs
- CT scan of the bone and soft tissue in the legs
The type of LLD will determine the treatment that a person receives.
Treating functional LLD
The treatment for functional LLD typically involves physical therapy, massage, and specific exercises to correct areas of imbalance and weakness. It is also important to correct poor posture.
The exact type and number of interventions that a person needs will depend on the underlying cause and severity of the LLD.
Exercising and functional LLD
Exercises may help correct some functional LLDs. However, it is important that people use the correct stretching and strengthening techniques. They should also take care to exercise the side of the body that will help correct the LLD.
To avoid causing further issues, it may be sensible to seek the help of a physical therapist. The therapist can identify areas of imbalance and recommend appropriate exercises.
Treating structural LLD
Correcting structural LLD is less straightforward. Treatment typically depends on the difference in length between the legs.
Some potential treatment options include:
A shoe lift
A person who has mild LLD of less than 1 inch may benefit from wearing a shoe lift inside the shoe on the shorter leg. A shoe lift can alleviate back pain and improve a person’s gait.
Surgery
Surgery may be necessary to treat more significant LLDs. Several surgical options are available, each of which aims to do one of the following:
- shorten the longer leg
- lengthen the shorter leg
- inhibit the growth of the longer leg
Following surgery, people will require regular follow-up visits to the doctor’s office. They will also need extensive rehabilitation that includes exercise and physical therapy.
Having one leg longer than the other is a relatively common occurrence. A leg length discrepancy may be functional or structural in nature.
Minor discrepancies often cause no symptoms or problems. However, moderate-to-severe asymmetry may cause issues with walking and posture, and it can contribute to hip and back pain.
People should see a doctor if they suspect that they or their child has LLD. A doctor can diagnose the condition and recommend appropriate treatments.
Leg length discrepancy can be one of two types. One type is structural, where there is an actual, physical difference between the same bones in each limb. For example, a femur or other specific bone may actually be shorter in one leg than in the other. The other kind of leg length discrepancy is called a functional discrepancy. In a functional discrepancy, bones in the leg are of equal length, but some other factor creates a discrepancy. This is often related to muscle tightness which creates a problem in symmetry.
Symptoms of Leg Length Discrepancy
A slight difference in leg length may not lead to symptoms; however, significant discrepancies can affect the quality of life, make some activities difficult, and even harm other bone structures. Here are some symptoms people may experience with leg length discrepancy:
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Limping
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Gait Problems
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Stress Fractures
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Osteoarthritis
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Joint Pain
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Back Pain
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Hip Pain
Exercises for Leg Length Discrepancy Symptoms
To ease symptoms you can try out some exercises that can help build strength and improve flexibility. You should talk to your doctor when starting a new exercise program and begin slowly, building in intensity in order to avoid injury.
Sidekicks
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Stand straight with feet shoulder length apart. Make fists and draw your arms back so that your hands are in front of your chest, in a defensive position.
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Lean to the side so that your body weight is resting on your longer leg. Inhale deeply, bend and lift the leg that is shorter until your knee is at the same height as your hip, keeping your foot pointed straight ahead of you.
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Exhale, kicking your shorter leg out and to the side, flexing the leg fully, and keeping your foot at the same height.
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Return to the position in step #2, and repeat four to five times.
This exercise may take some practice, so take it slow and don’t strain yourself. Work up to multiple sets a day and slightly raise the height of your kicks as you become more comfortable with the exercise.
Hamstring Stretch
Try out hamstring stretches to lengthen the muscles in your upper leg. Perform this stretch near a couch or at the corner of a wall.
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Lie on your back on the floor.
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Keep your longer leg on the floor and put your shorter leg against the arm of a couch or against a wall, keeping the leg elongated. You can gently push the knee so that the raised leg is as straight as possible. You should feel a stretch in the back of the raised leg.
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Hold the position for 10 seconds when you are first starting this exercise and work up to tolerating the hold for 30 seconds.
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Repeat four to five times for a complete set
Try to do at least two sets a day of this exercise. The tension should be a comfortable stretch, not painful. Lower the intensity if you feel discomfort.
Hip Adductor Stretch
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Lie down on your back, placing your feet together, with your soles flat on the ground.
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Slowly allow your knees to fall to the sides, noticing a gentle stretch through your inner thigh.
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Hold the position for 10 to 30 seconds and repeat four to five times.
Alternatively, you could do a hip adductor stretch in the seated position:
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Sit cross-legged on the ground. Your feet should be placed so the soles are together.
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Let your knees fall to the side to feel the gentle stretch in the inner thigh.
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Deepen the stretch by leaning your torso forward. Keep your upper body straight and move slowly to prevent strain.
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Hold the position for 10 to 30 seconds and repeat four to five times.
Hip Flexor Stretch
For a simple exercise for your hamstrings, lower back, and upper thigh, try a knee to chest stretch.
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Lie on your back with both of your legs extended.
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Slowly pull one knee to your chest, while keeping the other leg straight. Make sure to keep your lower back pressed to the ground.
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Hold the stretch for 30 to 90 seconds.
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Repeat with the other leg. Do four to five repetitions of the stretch.
Surgical Treatment for Leg Length Discrepancy
Exercises for leg length discrepancy can sometimes help with pain and mobility issues, but exercises will never be able to compensate or change a limb discrepancy. Especially if your leg length discrepancy is significant (more than 1.5 centimeters) or causing stress fractures, pain, or other issues, exercises may not make a significant quality of life difference, and limb lengthening surgery may be recommended.
Contact a Trusted Expert for Help
At Height Lengthening Institute, our specialists are able to provide a proper diagnosis and treatment for leg length discrepancy and other complex orthopedic conditions. Our experts, led by Dr. Shahab Mahboubian, are highly skilled and have received the best training from renowned orthopedic institutions.
Topics: Limb Discrepancy / Limb Lengthening