In a survey of 6000 children between 9 and 10 years of age, 122 were found to have unilateral or bilateral hallux valgus. These children were randomly assigned to no treatment or to the use of a foot orthosis. About three years later 93 again had radiography. The metatarsophalangeal joint angle had increased in both groups but more so in the treated group. During the study, hallux valgus developed in the unaffected feet of children with unilateral deformity, despite the use of the orthosis.