People with hypermobile Ehlers-Danlos syndrome (hEDS) have larger spaces in the shoulder joint than those without the condition, and this anatomical difference may help to explain their shoulder pain, a study has found.
The findings may also have implications for designing exercise programs for people with hEDS.
The study was published in the Journal of Shoulder and Elbow Surgery, and is titled “Subacromial space outlet in female patients with multidirectional instability based on hypermobile Ehlers-Danlos syndrome and hypermobility spectrum disorder measured by ultrasound.”
hEDS, the most common type of EDS, is characterized by joints that are able to move more than normal and are frequently dislocated. The shoulder is commonly affected in hEDS — an estimated 85% of patients experience shoulder pain, and more than half report shoulder dislocations. The reasons for this, however, aren’t fully understood.
To gain more insight into the shoulder structure of people with hEDS, researchers examined the shoulder joint through ultrasound.
The team was particularly interested in two measurements: the thickness of the supraspinatus tendon (SST), which is the main tendon in the shoulder that helps connect the arm to the chest; and the distance — called acromiohumeral distance (AHD) — between the humerus (the bone in the upper arm) and the acromion (the outer edge of the shoulder).