Hypermobility of the joints in juvenile episodic arthritis/arthralgia.

It has been suggested that hypermobility of the joints may predispose children to the development of arthritis or arthralgia. To determine the normal frequency of hypermobility, 260 normal schoolchildren (5 to 17 years of age) were examined. In addition, 34 patients with juvenile rheumatoid arthritis (JRA) and 32 children with juvenile episodic arthritis/arthralgia (JEA) were tested. Any child who met at least three of the following criteria was considered to have joint hypermobility: (1) passive apposition of the thumbs to the flexor aspect of the forearms; (2) passive hyperextension of the fingers so that they lie parallel with the extensor aspect of the forearms; (3) hyperextension of the elbows greater than 10 degrees; (4) hyperextension of the knees greater than 10 degrees; (5) flexion of the trunk with knees extended so the palms rest on the floor. Thirty-two (12%) of 260 normal schoolchildren and 21 (66%) of 32 with JEA had hypermobility. Further, a significantly higher proportion (23 of 126) of normal girls than normal boys (nine of 134) had hypermobility (chi 2 = 8.0, P less than 0.005). Hypermobility was not common in children with JRA. These findings support the hypothesis that hypermobility may be an important factor in the cause of JEA.