Three dimensional radiological imaging of normal lower-limb alignment in children

Abstract

Purpose: Our study aimed at evaluating age- and gender-specific references describing lower-limb alignment in a large population of children using an accurate and reliable method (EOS 2D/3D).

Methods: From our database, we selected 523 EOS records suitable for 3D modelling representing age groups between two and 16 years in which no relevant deviation influencing lower-limb biomechanics could be observed (the majority of the examined population had mild scoliosis). We performed reconstruction of both lower limbs, thus obtaining the value of the mechanical tibiofemoral angle (mTFA) and the femoral mechanical axis-femoral shaft angle (FM-FS) and calculated the anatomical tibiofemoral angle (aTFA) from previous parameters. Statistical analysis was carried out using the Kolmogorov-Smirnov test, Spearman correlation, regression analysis and Welch test.

Results: The aTFA reaches its maximum by the age of three years: 13.07° in boys and 10.73° in girls; it then varies ∼4.44° in both genders. By the age of three years, the mTFA reaches 8.04° in boys and 4.85° in girls; it starts to decrease to -1.47° in boys and 0.13° in girls. By the age of three years, FM-FS increases to 5.02° in boys, then fluctuates at ∼4.08°, while in girls, it increases to 5.87°, then fluctuates at ∼4.24°.

Conclusions: The pattern found in this study confirms the results of previous publications investigating Caucasian populations; however, absolute values differ significantly in several cases.

Keywords: Children; EOS 2D/3D; Femoral mechanical axis-femoral shaft angle; Lower-limb alignment; Tibiofemoral angle.