Hypermobility may lead to arthritic joints

Adolescents who impress their friends with feats of double-jointedness might be setting themselves up for pain or arthritis by the time they are young adults, according to a new study from the United Kingdom that examined the long-term consequences of joint hypermobility in teenagers.

Researchers recruited 2,900 14-year-olds from the Children of the 90s Avon Longitudinal Study of Parents and Children and evaluated them for joint hypermobility as defined by their Beighton scores-6 or higher on the 9-point scale. Nearly 5% of participants were found to be hypermobile. Girls were more affected than boys (7.2% vs 1.3%, respectively).

They also evaluated musculoskeletal pain using questionnaires when the participants were aged about 18 years. At this visit, 45%-again, more often girls than boys-reported having pain for at least 1 day within the past month. Sixteen percent reported moderately troublesome musculoskeletal pain in the lower back; 9.5% in the shoulder; approximately 9% in the upper back, neck, or knee; and 7% in the ankle or foot. No equivalent relationships were noted for the spine, elbows, hands, or hips.

Findings showed that children with hypermobility in the shoulder, knee, ankle, or foot when aged 14 years were at almost double the risk for having pain in those joints when they were 18. Children with hypermobility who also were obese increased their risk of knee pain 11-fold by age 18 compared with those without hypermobility.

Joint hypermobility allows an unusually wide range of movement because of excessive laxity of articular ligaments. The researchers say their study only suggests that joint hypermobility predisposes to pain at joints that are bent or stretched outside their normal range of motion. However the same mechanical factors may explain the tendency of these sites to develop osteoarthritis later in life.