Joint Hypermobility

This page is for persons who suspect that they may have a physiological problem that prevents them from getting numb at the dentist’s office.  To my knowledge, Joint hypermobility syndrome, and its variants, especially the severe form known as  Ehlers-Danlos syndrome are the only physiological disorders that have been associated with causing dental patients to become refractory to local anesthesia (in other words, it is very difficult to get the patient numb).  This page may help you to decide whether you fit into this category.  My (limited) experience with Marfan’s syndrome, which is a related disorder, has lead me to believe that patients suffering from Marfan’s do NOT suffer difficulties with anesthetics related to their condition.

Joint Hypermobility Syndrome (JHS) also called HyperMobility Syndrome (HMS), is  one of a group of inherited conditions which affect the connective tissues of the body.  It is estimated that 10%-15% of normal children have hypermobile joints, or joints that can move beyond the normal range of motion.  Patients with these conditions are more prone to joint injuries than patients without.  The problems associated with JHS seem to diminish with age, and persons born with less severe forms of HMS may be unaware of their condition.  The most severe variant of HMS is called Ehlers-Danlos syndrome.  Persons with this rare variant generally are well aware that they have some sort of joint or muscle problem, even if they do not know what is causing it.

Studies have suggested that as many as half of JHS patients have enhanced pain perception as well as noticeable pain in multiple sites in the body. Many seem to respond poorly to local anesthetics (i.e., at the dentist or during surgery) and require larger dosages for effective pain control.  Most of the evidence for the lack of efficacy of local anesthetics in patients suffering from less severe form of HMS is anecdotal, so it is difficult to say with certainty that a patient who seems refractory to local anesthetics is in fact suffering from a side effect of an undiagnosed case of JHS.  If a refractory patient has a history of a lot of accidental joint injuries, spontaneous joint pain or knows he or she is “double jointed”, this would be a reasonable avenue to explore.

In patients suffering from the various forms of HMS, the local anesthetic will produce numbness, but it may be of insufficient intensity or duration to complete the dental procedure without repeated injections.  The reason probably involves the rapid absorption of the anesthetic solution into the bloodstream due to the defective nature of the connective tissues in the surrounding blood vessels.  If the anesthetic solution cannot remain in place long enough to take effect, then the patient will not get numb.  The only known way to overcome this problem is to give repeated, frequent injections during the procedure and to use long acting anesthetics such as Marcaine (bupivicaine) with vasoconstrictor.

The following list will help the patient to decide if he or she may suffer from JHS. Click here for the reference:

  • Can you now (or could you ever) place your hands flat on the floor without bending your knees?
  • Can you now (or could you ever) bend your thumb to touch your forearm?
  • As a child did you amuse your friends by contorting your body into strange shapes OR could you do the splits?
  • Do you consider yourself double-jointed?

Physicians may want to assess the nine-point Beighton hypermobility score (Add one point on each side if the patient can perform the task for the first four exercises. The hypermobility score will have a maximum of nine points if all are positive. A score greater than or equal to 4/9 indicates widespread hypermobility.

jointhypermobilitytableThe Brighton criteria for joint hypermobility syndrome (JHS).   JHS is diagnosed in the presence of two of the following major criteria, or one major and two minor criteria, or four minor criteria. Two minor criteria will suffice where there is an unequivocally affected first-degree relative


  • Beighton score of 4 out of 9, or more (either currently or historically)
  • Arthralgia for longer than 3 months in four or more joints (Arthralgia means “joint pain”)


  • A Beighton score of 1, 2 or 3 out of 9 (0, 1, 2 or 3 if aged 50+)
  • Arthralgia in 1–3 joints, or back pain or spondylosis , spondylolysis/ spondylolisthesis
  • Spondylosis is spinal degeneration and deformity of the joint(s) of two or more vertebrae
  • Spondylolysis is a defect in a specific part of a vertebra
  • spondylolisthesis is a forward dislocation of one vertebra over the one beneath it producing pressure on spinal nerves
  • Dislocation in more than one joint, or in one joint on more than one occasion
  • Three or more of the following soft tissue lesions
  • Epicondylitis is a painful inflammation of the muscles and soft tissues around an epicondyle, one of the components in a ball and socket joint
  • tenosynovitis is an inflammation of a tendon and its enveloping sheath
  • Bursitis is an inflammation of a bursa; frequently in the shoulder.  A bursa is A closed fluid-filled sac that functions to provide a gliding surface to reduce friction between tissues of the body
  • Marfanoid habitus (tall, slim, arm span >height, arachnodactyly (long thin fingers)
  • Skin striae (stretch marks), hyperextensibility (the skin doughy, and velvety to the touch, thin skin and may have abnormal scarring
  • Eye signs: drooping eyelids, or myopia (short sightedness), or anti-mongoloid slant (downward slant to the eyes)
  • Varicose veins, or hernia, or uterine/rectal prolapse