About generalised joint hypermobility (GJH)
The term generalised joint hypermobility (GJH) is used when a child has several joints that are more flexible than usual. This happens when the connective tissue which makes up the joint structures (capsule and ligaments) is more compliant (more easily stretched) than usual.
Generalised joint hypermobility is quite a common occurrence - in fact it is just a normal variation in the way joints are put together. Most ballet dancers and gymnasts have a degree of joint hypermobility - which means that you can be hypermobile, strong, active and fit.
Yet many children with hypermobile joints have movement difficulties. Why is this and what can be done to overcome these difficulties?
A word about terminology
The term Joint Hypermobility Syndrome refers to a health condition which includes joint hypermobility along with pain and loss of function and as well as with several related symptoms such as fibromyalgia, anxiety, low blood pressure and fatigue.
Some people with very hypermobile joints which are unstable and may or may not partially dislocate also have a diagnosis of Ehlers Danlos Syndrome (Hypermobility Subtype). Ehlers Danlos is a genetic disorder which affects the structure of the connective tissue that holds the joint in place (joint capsule and ligaments) and connects the muscles to the bones via tendons and fascial sheaths. The poorly formed connective tissue also affects the skin which is velvety and very pliable (easily stretched).
Some medial experts do not differentiate clinically between JHS and Ehlers Danlos (Hypermobility Type). Please see the article by Tofts et al (2009) The differential diagnosis of children with joint hypermobility
A child with Erlos Danlos should be under the care of a;paediatric rheumatologist and a physiotherapist with experience in this condition.
Please note that this page provides information on children with generalised joint hypermobility. It does not apply directly to children who have Ehlers Danlos Syndrome (Hypermobility Subtype) or a diagnosis of joint hypermobility syndrome.
What is generalised joint hypermobility?
Joints are held together by a joint capsule and ligaments which are made up of connective tissue. Connective tissue is a stiff but pliable material that has just enough give to allow the joint capsule and ligaments to stretch a little bit when the joint is moved but still holds the joint surfaces together quite firmly.
In generalised joint hypermobility the connective tissue has more give than usual and as a result the joint surfaces are less firmly held together, are less stable and the joint is able to move further than normal.
How the ligaments work to keep the knee stable
Normally the knee can only extend to the point where the thigh and the lower leg are aligned in a straight line. In this picture you see the many sturdy ligaments at the back of the knee which serve to block the knee from extending beyond a straight line.
If these ligaments are lax, the knee can extend beyond a straight line. The child stands with the knees in hyperextension.
Children who stand with the knees in hyperextension will have a hollow back with the pelvis titled forwards.
Here you see the very many small ligaments that support the ankle joint and help to maintain the arches of the foot.
If these ligaments are very lax the child develops flat feet and a tendency to spraining the ankle joint if the muscles are not strong enough the provide the extra support that is needed. .
How hypermobility affects different joints
The elbow can be extended to form a backward angle.
The wrist can be bent so the the thumb touches (or nearly touches) the forearm.
|Hypermobile fingers can be bent back to 900.|
The joints in the fingers and thumbs also bend backwards.
The increased flexibility in the fingers make the hands less stable and the muscles have to work a lot harder when using the hands to grip, lift and manipulate objects.
The hips, spine and ankles are also affected by increased laxity in the connective tissue.
The legs flop out sideways when sitting flat on the floor, especially when the child is very young.
The child sits with a rounded back.
The child may have flat feet, especially if the hip muscles are tight and the ankle muscles are weak.
Hypermobile joints are easily injured
Children with joint hypermobility, muscle weakness and possibly poor coordination are more likely to complain of pain and tiredness and are more likely to suffer from joint sprains, leg pain and night pain..
The laxity in the joint ligaments make them more vulnerable to injury. Weak muscles are less able to able to protect the joints during during everyday activities that require a degree of fitness and agility.
Joint injury and pain can be reduced by strengthening weak muscles, increasing flexibility of tight muscles and improving coordination.
Read more: How do I know if my child has weak muscles?
What causes joint hypermobility?
The degree of compliance (stretchiness) in connective tissue is genetically determined. Between 10 and 20% of people have connective tissue that is more pliable ( less stiff) than usual. So some degree of joint hypermobility can be viewed as part of the normal variation in the structure of the connective tissue within the population.
Children with generalised joint hypermobility will usually have a parent or other close relative with hypermobility.
Having hypermobile joints is often seen as a plus factor, particularly in gymnastics and ballet dancing. To be a ballerina you need to have some degree of hypermobility.
Hypermobility is also not always associated with movement difficulties. In my experience as a children's physiotherapist, it is the combination of hypermobility, weakness, some muscle tightness and a very cautious nature that leads to movement difficulties.
How is joint hypermobility diagnosed?
The Beighton scale is most commonly used measure for diagnosing generalized joint hypermobility. This a nine point scale, measuring range of motion (ROM) at 8 joints plus the ability to put the hands down flat on the floor in standing.
The recommended cut-off point for a diagnosis of generalized joint hypermobility ranges between 5 and 7 for different clinicians and researchers.
Postural and movement difficulties children may have
Children with GJH often have difficulties with a range of everyday, classroom and playground tasks and activities. Poor general fitness along with muscle weakness and tightness in some muscles contribute to these difficulties especially if the child has a cautious nature and avoids tasks that require physical effort.
Read more: Difficulties and FAQ's
Generalised joint hypermobility and flat feet
Many children with joint hypermobility (low muscle tone) have problems with flat feet. The inside border of the foot does not have a good arch and the heel bone is often angled outwards.
In addition children with flat feet often stand with their feet turned out, and sometimes with the feet far apart. This tendency to stand with the feet turned out and far apart places abnormal stresses on the feet and hinders effective push-off for walking, jumping and running.
Read more: Flat feet; not just a foot problem
Generalised joint hypermobility is associated with a range of physical difficulties
The increased compliance in the connective tissue that causes hypermobility in joints also affects other parts of the body leading to a number of problems, including:
Children with joint hypermobility often complain of leg and back pain
The combination of loose joint structures (ligaments and capsule) along with muscle weakness and some tight muscles causes abnormal stresses on knee joints which in turn leads to knee pain after exercise or at night. More about leg pain
Children with joint hypermobility may also experience back pain due to poor posture and muscle weakness.
Children with GJH often have a cautious and anxious nature
Hypermobility is also associated with a cautious nature. Cautious children often tend to avoid physical effort - which means that they do not get the exercise needed to strengthen their muscles to support their hypermobile joints.
Children with joint hypermobility may be very anxious and respond to challenging situations with refusal, freezing or outbursts. The anxious behavior is sometimes ascribed to a sensory processing disorder which can be a problem if the underlying anxiety is not addressed in the right way. Read more about very cautious children
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