Joint hypermobility: the use of a new assessment tool to measure lower limb hypermobility.

OBJECTIVES The aim of the study was to compare the use of a new assessment tool for diagnosis of hypermobility in the lower limb to the Beighton score for generalised hypermobility. METHODS Three groups of children were compared (n = 225) and included a "normal" population of 116 school children, a "possible hypermobile" group of 88 children attending afoot and gait clinic and a "known hypermobile" group of 21 children referred from a paediatrician or rheumatologist. The Beighton score was used to measure generalised hypermobility. The Lower Limb Assessment Score was used to measure hypermobility in the lower limbs. RESULTS The Lower Limb Assessment Score was able to distinguish between the three groups of children better than the Beighton score. At a threshold of 5/9 indicating hypermobility, the Beighton score identified hypermobility in 34% of school children; the lower limb score identified hypermobility in 21% of school children after a threshold was identified. There was disagreement between the scores in school children where 26.7% of children appeared to have a positive Beighton score that was not accompanied by a positive lower limb score. In the "known hypermobile" group the Beighton score was positive in only 10% of children when the lower limb score was negative for hypermobility. CONCLUSION In this group of school children, the Beighton score appeared to over-diagnose hypermobility at the threshold of 5/9. Specific thresholds for diagnosis need to be set dependant on the age and ethnic group of the population being studied. The Lower Limb Assessment Score may be a useful score for health professionals specifically interested in lower limb hypermobility.