Reference ranges for knee height in Argentine children and adolescents aged 2 to 18 years

Measurement of height is essential in the anthropometric assessment of growth and nutritional status. In some conditions, height measurement may be difficult or impossible. Proxy measurement such as knee height (KH) have been proposed to predict stature in such cases, but reference percentile ranges and charts for healthy, well-nourished children are currently unavailable. This study was designed to develop sex-specific KH reference percentile ranges and charts in Argentine children ranging from 2 to 18 years of age.

We collected and analyzed cross-sectional data for KH from 861 Argentine children and adolescents aged 2 to 18 years. Generalized additive models for location, scale, and shape were used to calculate semiparametric smoothed percentile reference ranges, and charts by age and sex. Linear regression and correlation analyses were performed to know the association between KH and height.

The new reference ranges show that KH growth rose sharply until puberty. Peak KH velocity occurs 1 year earlier than peak height velocity. At puberty KH growth decelerated rapidly in females and increased slightly until 15 years and plateaued at this age, while it had a more gradual deceleration in males up to 11 years old, later increased slightly until 17 years and plateaued at this age. The correlation coefficient between height and KH was r = 0.98 for both sexes (p < .001).

The new reference percentile ranges for KH measures for healthy children and adolescents provide a useful growth and nutritional assessment tool in a wide variety of settings. KH has a strong agreement with stature.