Hypermobility (joints)

Associated conditions

Joint hypermobility may be associated with other conditions. These include ADHD, autism, dyspraxia, fibromyalgia, hereditary connective tissue disorders, mitral valve prolapse, and anxiety disorders such as panic disorder.^{[10][11][12][3][13]} Joint hypermobility does not cause these other conditions. Most people with joint hypermobility do not have them. In people who do, the underlying cause can be a general syndrome that affects the whole body and brain (such as Autism or Fetal Alcohol Spectrum Disorders), or a genetic condition or disease that affects certain tissues (such as Ehlers-Danlos syndrome or lupus).

Medical conditions that can cause joint hypermobility include FASDs, Stickler syndrome, Ehlers–Danlos syndrome,^[14] Marfan syndrome,^[14] Loeys–Dietz syndrome, rheumatoid arthritis, osteogenesis imperfecta,^[14] lupus, polio, Fragile X syndrome, Down syndrome,^[14] Morquio syndrome, cleidocranial dysostosis and myotonia congenita. All have other diagnostic criteria as well.

Syndromes

Hypermobility syndrome is generally considered to comprise hypermobility together with other symptoms, such as myalgia and arthralgia.^[22] Hypermobility is reported more often in females than males.^[26] Hypermobile joints are also relatively common among children, though this is often benign.^[27]

Current thinking suggests four causative factors:

• The shape of the ends of the bones — Some joints normally have a large range of movement, such as the shoulder and hip. Both are ball-and-socket joints.^[28] The joint ends of bones finish their growth last, so children tend to have more flexible joints than adults; children may "grow out of" hypermobility as their bone ends fully develop.^{[citation needed]} A shallow socket will lead to a relatively large range of movement. If the hip socket is particularly shallow, then the hip may dislocate easily.^[28]
• Ligament problems— Ligaments are made of several types of protein fiber, including elastin and collagen. Gymnasts and athletes can voluntarily acquire hypermobility in some joints^[28] by stretching healthy ligaments over time. However, weak or abnormally long ligaments can cause unstable hypermobile joints.^{[citation needed]} Protein deficiencies may weaken ligaments. Some hormones may alter the structure of collagen proteins. For example, in late pregnancy, relaxin allows the ligaments of the pelvis to lengthen so the head of the baby can pass.^[28]
• Muscle tone—Opposing sets of muscles are attached to bones to move joints in various directions. The tone of muscles—a mild basic level of contraction that protects joints and organs—is controlled by the nervous system. Neuromuscular problems can cause loss of muscle tone, increasing the range of movement possible and removing the muscles' protection of the joint. Lack of exercise also weakens the muscles that support and anchor highly flexible joints such as the shoulder, hip, wrist, and ankle.^{[citation needed]}
• Proprioception—Disorders such as dyspraxia affect the brain's communication with the sensors that detect the motion and position of the body in space.^{[citation needed]} A person with poor proprioception may habitually hyperextend joints during normal activities such as walking and sitting, because they can't internally sense where the joint is.^[28] If stress/pain perception is also affected, they may not experience hyperextension as uncomfortable until an injury occurs.^{[citation needed]}

Hypermobility can also be caused by genetic or developmental disorders that reduce the strength of the connective tissue the body can make. Commonly, hypermobility is dismissed by medical professionals as nonsignificant, though it may be a sign of a systemic problem.^[29]

Ehlers–Danlos syndrome hypermobility type

Joint hypermobility is often correlated with hypermobile Ehlers–Danlos syndrome (hEDS, known also by EDS type III or Ehlers–Danlos syndrome hypermobility type (EDS-HT)). Ehlers–Danlos syndrome is a genetic disorder caused by mutations or hereditary genes, but the genetic defect that produces hEDS is largely unknown. In conjunction with joint hypermobility, a common symptom for hEDS is smooth, velvety, and stretchy skin. When diagnosing hEDS, the Beighton Criteria are used, but are not always able to distinguish between joint hypermobility syndrome and hEDS.^[30]

Ehlers–Danlos hypermobility type can have severe musculoskeletal effects, including:

• Jaw laxity that may make an individual's jaw open and close like a hinge, as well as open further than the average.
• Neck pain that can lead to chronic headaches and is usually associated with a crackling or grinding sensation (crepitus).
• The spine may end up in a "round back" or inversely may extend too much into hyperlordosis. Individuals may also experience scoliosis.
• Joints commonly associated with hypermobility (wrists, knees, ankles, elbows, shoulders) may be at more severe risk to dislocate or strain.

Beighton criteria

As of July 2000, hypermobility was diagnosed using the Beighton criteria. In 2017, the criteria changed, but still involve the Beighton score.^[34] The Beighton criteria do not replace the Beighton score but instead use the previous score in conjunction with other symptoms and criteria. HMS is diagnosed in the presence of either two major criteria, one major and two minor criteria, or four minor criteria.^{[citation needed]} The criteria are:

Beighton score

The Beighton score is an edited version of the Carter/Wilkinson scoring system which was used for many years as an indicator of widespread hyper-mobility. Medical professionals varied in their interpretations of the results; some accepting as low as 1/9 and some 4/9 as a diagnosis of HMS. Therefore, it was incorporated, with clearer guidelines, into the Beighton Criteria.^{[citation needed]} The Beighton score is measured by adding 1 point for each of the following:

• Placing flat hands on the floor with straight legs
• Left knee bending backward
• Right knee bending backward
• Left elbow bending backward
• Right elbow bending backward
• Left thumb touching the forearm
• Right thumb touching the forearm
• Left little finger bending backward past 90 degrees
• Right little finger bending backward past 90 degrees^[35]

The Beighton score has been widely used among athletes for screening purposes. It does not appear to be a valid scale when used for this purpose: there exists a statistically significant correlation between the score and the athlete's passive shoulder and hip ranges of motion, but the difference is small enough to be buried by measurement error.^[36]

Exercise

It is recommended that hypermobile individuals remain fit, to prevent pain and fatigue.^[9] Regular exercise and exercise that is supervised by a physician and physical therapist can reduce symptoms because strong muscles increase dynamic joint stability. Low-impact exercise such as closed kinetic chain exercises are usually recommended as they are less likely to cause injury when compared to high-impact exercise or contact sports.^[37]

Strength training can be used to stabilise muscles around hypermobile joints. Hydrotherapy can be a beneficial medium for muscle training.^[38] Some isometric exercises can also be beneficial.^[39] Coordination may be improved through balance exercises.^[38]

High impact sports are not recommended.^[9]

Medication

Medication is used in a similar way as for other chronic pain conditions,^[39] and can be used as a treatment for related joint pain.^[40] Nonsteroidal anti-inflammatory drugs and acetaminophen are used to treat pain.^[39] Opioids are often used, and prescribed for many with hypermobile Ehlers-Danlos syndrome.^[41]

Lifestyle modification

For some people with hypermobility, lifestyle changes decrease symptom severity. Regular movement is recommended, and support devices can be used. These include shaped keyboards to assist posture, insoles to support flat feet, and wide grip pens. Pillows and cushions can be used to support joints.^[42]

Other treatments

Bracing can be used for unstable joints, though it has weak evidence as a pain management strategy.^[40] Neuromuscular taping can help prevent injury.^[39] TENS units are sometimes used for pain relief.^[42] Heat and cold treatment can also help to relieve pain, and have no adverse effects.^[40]