On occasion, a patient will come to my office and proclaim, “I'm double-jointed!” A second later, I become a one-man audience to Circque de Solei performance of the hands.
For starters, the term “double-jointed” is commonly used, but it is not accurate. Double joints do not exist. More appropriately, this highly bendable condition is due to exceptionally stretchable joints. In the medical community, this condition is referred to as joint hypermobility, joint hyperlaxity, or ligament laxity.
Joint hypermobility is largely caused by genetic factors, because the shape and structure of ligaments, tendons, and bones determines the amount of joint motion. The severity of the condition can range from mild to severe, as seen in Ehlers-Danlos syndrome.
Approximately, one out of every 100 people has hypermobile joints. It is more prevalent in females and young people. With hypermobile joints, there is an increased risk of injury and osteoarthritis, especially in fingers. Please, don't worry - in most cases, ligament laxity is a harmless condition.
If you feel inclined to wow your friends and relatives with your “double joint” performance, make sure to tell them that Dr. Izadi thinks you are special!