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Injury

The most common cause of limping is a minor injury. Injuries in children are usually obvious, but persistent limping after an injury can be a sign that there is an underlying minor fracture (broken bone).

Infection and Inflammatory Disease

Other common causes of limping in children are infections and inflammatory conditions.

Infections. Bacterial infections can settle in growing bones and adjacent (nearby) joints, and often will cause pain and limping in younger children.

Inflammatory diseases. Many types of inflammatory disease, such as juvenile arthritis, can affect joints and cause pain, swelling, and limping.

Transient synovitis/toxic synovitis. Some viral illnesses cause increased inflammation throughout the body, and joints may temporarily swell and become painful.

Other Causes

Most other causes of limping are uncommon. Serious bone diseases and nervous system disorders are very rare.

Tumors. Different types of tumors can grow into bone and soft tissues, producing pain and limping. For more in-depth information: Bone Tumor and Metastastic Bone Disease

Congenital abnormalities. Certain problems that develop before a baby is born — such as congenital hip dislocation — can cause limping. These problems often cause a difference in leg lengths, and the limping is usually noticed when toddlers begin to walk. For more in-depth information: Lower Limb Length Discrepancy

Legg-Perthes Disease. In this condition, there is not enough blood supply to the hip. Without a good blood supply, the top of the thighbone (the ball of the "ball-and-socket" joint of the hip) can flatten. This condition usually occurs between the ages of 4 and 10 years in otherwise healthy children.

For more in-depth information: Perthes Disease

Slipped Capital Femoral Epiphysis. This occurs when the ball part of the hip joint slips off the upper thighbone due to a weakened growth plate. This occurs just before puberty between  the ages of 9 and 15 years.

For more in-depth information: Slipped Capital Femoral Epiphysis

Diskitis. The disk spaces between the small bones in the spine can become inflamed and irritated, which can cause a child to limp.

Nervous system disorders. Disorders of the nervous system can cause weakness or tightness in the muscles, which can cause a child to walk differently.

This chart outlines the most common causes of limping, along with general symptoms.

Medical History

When you take your child to the doctor because of an unexplained limp, the doctor will first discuss your child's medical history, recent activities, and overall health. They will also ask you to describe the limp and when it occurs.

The more information that you can provide the doctor, the better they will be able to determine the cause of the limp. For example:

• If you have a family history of rheumatoid arthritis, knowing this could help the doctor sort out possible causes of your child's limp.
• If your child has recently had a cough, sore throat, or rash, it is possible that a viral response is causing joint inflammation.
• If your child has a fever, there is more concern that the limp is caused by a bone or joint infection.

Physical Examination

After discussing your child's symptoms and medical history, the doctor will examine your child. Because long pants cannot be worn during the examination, some children are more comfortable wearing their own shorts or bathing suit to the appointment.

• The doctor will watch your child walk. Younger children cannot always describe where they are hurting, but careful observation can often reveal which side of the body is affected. For example, if a child leans to one side when standing on one leg, it is often a sign that they may be unconsciously trying to take some of the weight off of the painful hip. If one foot is spending less time on the ground than the other, it may be a sign of pain in that leg.
• The doctor will feel your child's legs for tenderness, swelling, or bruising. It may be possible to determine if the problem is in a muscle, a joint, or a bone. Your child's arms will also be examined to check for associated injuries.
• The doctor will examine your child's joints — such as the hip and knee — for pain, swelling, and loss of range of motion. Decreased movement in any direction, or pain at the extreme ranges of motion, point to that joint as the cause of the limp.
• If it seems like the pain is coming from your child's knee, the doctor will do a very careful examination of the ligaments and movement of the knee. Swelling or abnormal movements can indicate a ligament injury.
• The doctor will also check your child's spine for pain, stiffness, curvature (scoliosis), or unusual skin markings (rash or spots).
• If your child does not have any pain, the doctor will look for evidence of congenital abnormalities or nervous system disorders that may be causing the limp. Some of the signs of a nervous system disorder include a tight Achilles tendon (heel cord), claw toes, or a very high arch on one foot. In addition, a careful neurologic exam can detect muscle strength or reflex imbalances that can indicate a problem involving the brain, spinal cord, or muscles in the arms and legs.

X-rays

Your child's doctor may recommend X-ray images to help determine the exact cause of your child's limp.

• X-rays will be taken of areas of the body where there is pain, swelling, or loss of range of motion. The doctor may want images of these areas from different angles, such as the front, side, and back.
• X-ray images of your child's unaffected side (for example, the other leg) may also be taken to compare with the painful affected side.

Other Imaging Tests

If X-rays are normal and the cause of the limping is unclear, a bone scan can be helpful to detect a subtle fracture, bone infection, or bone tumor. However, the use of bone scans in diagnosis has become less common.

Your child's doctor may order a magnetic resonance imaging (MRI) scan if your child's pain and limping are well localized (limited to one area) but the X-rays are normal. MRI scans can show joint swelling, fractures, infections, and bone tumors. For younger children, this form of imaging often requires the child to be sedated (given medicine that makes them relax or sleep during the scan).

The doctor may order an ultrasound to look for fluid in a joint. This is particularly useful for the hip, where swelling is hard to see.

Laboratory Tests

Laboratory tests are particularly useful in inflammatory conditions, such as bacterial and viral diseases, and may be helpful to identify joint swelling caused by juvenile rheumatoid arthritis or Lyme disease.

Your child's doctor may order blood tests or request to take a sample of joint fluid (using a needle and syringe, a simple procedure called joint aspiration). These tests will help make a diagnosis or to rule out more severe causes of limping.