RESUMO
BACKGROUND: In the absence of age and sex-specific normative data for postnatal growth of the calcaneus, it has been hypothesized that the growth of the calcaneus would simulate growth of the foot. METHODS: A total of 860 normal lateral foot radiographs, 50 (25 female and 25 male) for each year of development from 1 to 18 years, and 10 radiographs from birth till 1 year, were measured for the length and height of the calcaneus, Bohler angle, the appearance, fusion and fragmentation of calcaneus apophysis, and the height and width of apophysis. Nonlinear curves were fit to a growth chart of the calcaneus, and the results were superimposed on the historical growth charts of the foot, stature, and long bones (femur, tibia). The ratio of calcaneus length to apophysis height was calculated. RESULTS: Growth of the calcaneus does not simulate growth of the foot (which attains 50% of its mature dimension by the age of 1 y in girls and 1.5 y in boys), but simulates the growth of the long bones, which attain 50% of their mature length after the age of 3 years in girls and 4 years in boys. Bohler angle remains within normal limits across all ages. When the length of calcaneus is triple the height of its apophysis, 80% of calcaneus growth is complete. CONCLUSIONS: We provide normative data for postnatal growth of the calcaneus. On the basis of these data, the assumption that growth disturbance in children affects the length of the calcaneus proportionately less than similar disturbances in the long bones, is false. Children <3 years have at least 50% of growth remaining. Bohler angle should be maintained at all ages. CLINICAL RELEVANCE: This study of postnatal growth of the calcaneus provides age and sex-based normative data to predict growth pattern of calcaneus.