Adolescent idiopathic scoliosis and joint laxity. A study with somatosensory evoked potentials.

To assess the existence of disturbances in proprioception in adolescent idiopathic scoliosis and an hypothetical relationship with generalized joint laxity, a blind comparative study of short-latency somatosensory evoked potentials by posterior tibial nerve stimulation was designed. One hundred twenty-one subjects were included: fifty-two were diagnosed as having adolescent idiopathic scoliosis, thirty-two met criteria for generalized joint laxity, twenty-one had curvatures with Cobb angles less than 10, and twenty-eight were matched control subjects; twelve subjects were initially seen with both adolescent idiopathic scoliosis and generalized joint laxity. We failed to find alterations in somatosensory evoked potentials in patients with adolescent idiopathic scoliosis that could suggest proprioceptive disturbances as a causative factor; however, in a subgroup of thoracolumbar curvatures we were able to demonstrate a functional alteration in somatosensory evoked potentials that could represent a neurologic basis for some curves considered as idiopathic thus far; generalized joint laxity seems to be implicated in this situation.