- Ehlers-Danlos Syndrome is a disorder of connective tissue that causes loose joints.
- Hip dysplasia is also associated with loose joints
- Most cases of hip dysplasia are not related to Ehlers-Danlos syndrome
There are genetic tests for Ehlers-Danlos Syndrome but these are generally unnecessary for hip dysplasia patients unless there are other problems from joint laxity. Nonetheless, some cases of Ehlers-Danlos Syndrome are overlooked in patients with hip dysplasia so it may be worth reviewing some of the differences.
Ehlers-Danlos Syndrome has thirteen recognized subtypes that range from severely loose connective tissue to generalized increased joint mobility. For the most severe type: the skin is very thin and stretchy, the blood vessels may enlarge and burst, hernias develop easily, multiple joints can dislocate, and visual problems are common. Fortunately, this is rare.
In contrast, a milder form known as “Hypermobility Type” or “Hypermobility Syndrome” is more common and can escape diagnosis more easily. A screening test for this condition is called the Beighton Score. A score of 4 or more out of a possible 9 points suggests joint hypermobility, but Ehlers-Danlos Syndrome is generally associated with joint pain in four or more joints that has lasted longer than three months.
The Beighton score is calculated as follows:
- One point if while standing forward bending you can place palms on the ground with legs straight
- One point for each elbow that bends backwards
- One point for each knee that bends backwards
- One point for each thumb that touches the forearm when bent backwards
- One point for each little finger that bends backwards beyond 90 degrees.
(Used with permission from the Hypermobility Syndromes Association (HMSA) site (https://hypermobility.org/help-advice/hypermobility-syndromes/beighton-score/).
It’s been known for decades that people with hip dysplasia may be loose jointed, but few hip dysplasia patients have connective tissue disorders that can be detected today. Female athletes who suffer anterior cruciate ligament injuries because of joint laxity are more likely to have mild hip dysplasia compared to uninjured female athletes. Dancers and gymnasts are very flexible and they also have a slightly greater frequency of hip dysplasia. Perhaps in the future we will know more about subtle differences in loose jointed people that are considered a variation of normal today. Genetic testing can determine whether a person has Ehlers-Danlos Syndrome or not, but this is rarely helpful unless there are multiple painful joints or other signs of abnormal skin and ligament laxity.
For more information, visit https://www.ehlers-danlos.com/what-is-eds/