Prevalence of late-onset tibia vara.

We wished to determine the prevalence of late-onset tibia vara in an at-risk population. From a group of 1,117 boys aged 13-19 years, we selected all those who weighed at least 210 pounds. The 140 boys (80 black, 60 white) who met this inclusion criterion were examined for varus alignment. Radiographs of the seven boys who screened positive showed that two boys had late-onset tibia vara. Both boys were black and weighed > 280 pounds. The prevalence of late-onset tibia vara in this obese adolescent black male population was 2.5% (two of 80 boys). Recently, the number of reported cases of late-onset tibia vara has increased dramatically probably owing to an increase in the prevalence of morbid obesity.