Joint hypermobility syndrome, popularly known as being double-jointed, may be a common but underrecognized disorder in adults that is difficult to diagnose and often mistaken for fibromyalgia or other conditions.
So said Matthew B. Carroll, MD, board-certified rheumatologist with Singing River Health System, Ocean Springs, Mississippi, during a presentation about hypermobility at the 2023 annual Internal Medicine meeting of the American College of Physicians in San Diego.
According to Carroll, the concept of a hypermobility spectrum disorder (HSD) associated with double-jointedness is relatively new and not part of the conventional nomenclature.
“One of the frustrations about HSD is that there really aren’t any good theories,” as to why some with hypermobility suffer from the syndrome while others do not, Carroll said.
Approximately 20% of the adult population has hypermobility, which affects women more than men and is more common in younger people. In children ages 3 to 19 years, 32% of girls and 18% of boys are hypermobile.
But the condition is not a diagnosis, “it’s a descriptor of a finding that you notice on a physical exam,” Carroll said.
When Flexibility Is a Problem
Although hypermobility often is benign and rarely progresses to more serious health issues, HSD can cause symptoms such as recurrent dislocations, joint pain, and other degenerative changes. Recent evidence suggests that abnormal bleeding may also accompany hypermobility.
A 2013 survey in the United Kingdom found that about 3% of respondents reported pain as a consequence of their hypermobility. Carroll hypothesized that up to a quarter of those diagnosed with hypermobility have some associated pain.
“We kind of think of hypermobility as either being benign or you kind of have it as a kid and grow out of it,” Carroll said. “But the reality is a lot of our patients keep that into adulthood and can have problems as a consequence.”
Because some of the symptoms of HSD, such as abdominal pain and fatigue, mimic other whole-body pain conditions, specifically fibromyalgia, Carroll said it likely is widely undiagnosed.
“I think a lot of these patients were diagnosed with fibromyalgia,” Carroll said. “It’s incumbent upon us to be able to start teasing some of those nuances out, or at least have rheumatology help you and other specialists figure out where you can go with these patients and their health.”
Causes of HSD
HSD can be both genetic and environmental in nature; sports injuries, spontaneous dislocations, and a fear of injury leading to a sedentary lifestyle should also be considered. The condition can overlap with Ehlers-Danlos syndromes, a rare group of inherited conditions that affect connectivity tissue.
Treating patients with HSD requires a multidisciplinary approach, including primary care, rheumatologists, geneticists, and orthopedists. If primary care physicians suspect their patient has hypermobility, they should explore this possibility before moving on to another diagnosis. Determining whether an adult has or had joint mobility can be determined through a series of simple questions:
Can you bend your thumb to touch your forearm?
As a child did you amuse your friends by contorting your body into strange shapes?
Do you consider yourself double-jointed?
“It gets really kind of muddy and really difficult to tease out, but I think it’s something that takes time in an iterative process to figure out,” Carroll said.
Treatment options for HSD are limited. No disease-directed pharmacologic agents exist and interventions in general lack rigorous studies to support their use. Carroll recommends anti-inflammatory drugs and physical therapy as first-line approaches. He also stressed that lifestyle interventions — particularly exercise and weight loss — are essential. The role of surgery at this time is unclear and only used in highly selected cases. An appointment with a geneticist could also be necessary to explore family history and look for Ehlers‐Danlos syndromes.
“You’re going to need several different specialists to try to really help our patients get back up and running,” he said.
Carroll reported no relevant financial relationships.
American College of Physicians (ACP-IM) Internal Medicine Meeting 2023. Presented April 28, 2023.
Robert Fulton is a journalist in Los Angeles.