What is benign hypermobility joint syndrome?
Benign hypermobility joint syndrome (BHJS) is a common source of joint or muscle complaints that often cause concern for parents, children and school personnel. Benign hypermobility describes looseness of joints that may be associated with daytime pain, nighttime awakening, or discomfort after exercise. Patients generally report multiple complaints of pain over a prolonged period. This type of general pain is often called, "growing pains," or "limb pains." Another commonly used term for BHJS is the benign type of Ehlers-Danlos syndrome ("type 3").
"Limb pains" and BHJS can be quite similar, but are different disorders.
What are the signs and symptoms?
Children or young adults with hypermobility usually have joint pain or mild swelling during the late afternoon, at night or after an exercise or activity. The pain is more common in the lower extremities, such as the calf or thigh muscles. The pain most often involves large joints such as the knees or elbows, but can involve any joint.
Swelling is not usually present, but when found is due to normal, activity-related trauma to the joints. Swelling can cause an increase in fluid within the joint cavity. Signs of inflammation, such as joint redness and heat, are usually absent. Fluid may come and go within hours.
The anatomy of a joint
The area where two bones meet is called a joint. All joints have a cavity containing a small amount of synovial fluid, which allows for movement. The attached tendons, muscles, ligaments and joint capsule hold the joint in its correct position. Looseness of these supporting structures allows a joint to have extra motion. Often, even normal activities that put stress on loose joints will irritate them.
To illustrate how a joint works, think of a door hinge and a doorstop. The hinge is like a joint, and the doorstop prevents the door from swinging too far and damaging the wall. Likewise, a joint with supporting structures that are loose or stretched will allow extra movement past the normal range of motion. This hyperextension can cause brief discomfort, swelling or pain in that area. The joint may also partially dislocate because of the loose supportive ligaments and joint structures.
Who is affected by BHJS?
The frequency of BHJS varies with sex, age and ethnic background. Girls tend to have more mobility (looseness) of the joints than boys of the same age. Younger children tend to have more pain complaints. Teenagers may have fewer symptoms because their muscles and joints tend to become tighter and stronger as they become older, and because they better understand the relationship between increased activity and discomfort.
When large groups of school children are tested, hypermobility is found in 7 to 40 percent of children. Between 8 and 11 percent of these children have hypermobility that can lead to pain after activities or at night. No one knows why some children develop discomfort, while others with equally hypermobile joints do not have pain or swelling.
There is often a family history of "loose-jointedness." There may occasionally be a patient and/or family history of congenital hip dislocations; scoliosis (curvature of the spine); elbow, kneecap or shoulder dislocations; or frequent ankle or wrist sprains.
How is BHJS diagnosed?
Assessment of children or young adults suspected to have BHJS does not require special equipment. Testing the range of motion of your child’s joints will determine if they are looser than normal. Five specific mobility tests are used for diagnosing BHJS, which are described to the right.
- The wrist and thumb can be moved downward so the thumb touches the forearm.
- The fingers (especially the 5th finger) can be extended back so they are parallel to the upper arm.
- When standing, the knees are abnormally bowed backward when viewed from the side.
- When fully extended, the arms bend further than normal (beyond straight).
- When bending at the waist, with the knees straight, the child or young adult can put his or her palms flat on the floor.
Many children with BHJS have flat feet.
Since the symptoms of hypermobility can sometimes mimic arthritis, laboratory tests may be required to ensure that your child does not have a more serious disorder (such as rheumatoid arthritis or other inflammatory conditions). Rarely, X-rays may be required.
How is BHJS treated?
Treatment is specialized for each child or young adult, based on his or her overall health, medical history, severity of pain or discomfort, and presence of other symptoms.
Basic strengthening and guided exercise programs can help your child to reduce flexibility and increase muscle strength to help prevent future injury.
Practicing joint protection techniques can help your child avoid over-stretching the joints at risk:
- Avoid sitting cross-legged with both knees bent (Indian-style)
- Bend the knees slightly when standing
- Wear shoes with good arch supports
- Decrease those unusual joint movements that hypermobile children often use to entertain their friends
- Avoid "popping" or "cracking" fingers or neck, or other joints.
Physical therapy including strengthening exercises and conditioning activities such as swimming, walking and skating are helpful to improve joint strength. Inactivity should be avoided. In addition, being overweight worsens one’s problem. Splints, braces, or taping may be recommended to protect affected joints during activities.
Proprioceptive (balancing) exercises may be helpful in reducing pain.
Since the underlying problem with hypermobility is joint looseness, rather than inflammation, most medications provide only limited relief. Taking aspirin or an over-the-counter nonsteroidal pain reliever, such as naproxen or ibuprofen, can reduce post-activity joint discomfort.
Among children who have a strong desire to continue competitive sports, a few families report benefits from taking these medications just before a sporting event, or right after the event.
What is the outlook?
Children with loose joints often do well in activities that "reward" flexibility, such as cheerleading, modern dance, playing a musical instrument, gymnastics, ballet, etc. However, decreasing or stopping some of these activities may be necessary if the child’s pain is unbearable.
Generally, BHJS is self-limited, meaning that most children’s symptoms improve as they become teenagers, because their increased muscle size and strength reduces joint looseness. However, some individuals retain life-long BHJS, have frequent discomfort and can become injured more easily.
BHJS rarely leads to arthritis later in life, although some patients may develop shoulder or kneecap problems if there are frequent dislocations, or if the cartilage around these or other joints becomes excessively worn.
A few patients continue with increased muscle pain from hypermobility as they become adults. These people remain at increased risk of trauma-related sprains, injuries, dislocations, intermittent swelling, backaches and post-exercise discomfort.
Some studies have found that older people who were hypermobile in youth have better functional capabilities compared to those without hypermobility.
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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 12/31/2008...#3971