Lower Limb Alignment in Indian Children: A Radiographic Analysis of Coronal Plane Parameters

Abstract

Indian children are known to have variations in the tibiofemoral angle as compared to children of other ethnicities. There is no study describing radiographic angles in coronal plane in Indian children. Our aim was to evaluate coronal plane alignment in Indian children. Database of radiographs between January 2011 and December 2019 was searched. Full-length standing radiographs of patients younger than 16years with unilateral congenital or post-traumatic or post-infective deformity were included. The radiographs were measured for mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), tibiofemoral angle (TFA), hip-knee-ankle (HKA) angle, lateral distal tibial angle, mechanical axis deviation (MAD), and mechanical lateral proximal femoral angle. Analysis of 221 lower limbs of 177 children is presented. There were 103 (58.2%) boys and 74 (41.8%) girls. Mean age was 8years, 6months (range: 2years, 1month to 15years, 11months). The mean mLDFA remained constant between 87° and 88° after the age of 5years. The mean MPTA remained around 88° after 8years of age. The mean MAD remained within 4mm of the midpoint of the knee after the age of 8years. The adult value of TFA was achieved after 8years of age. The mLDFA, MPTA, and mLPFA are significant predictors of change in the TFA. The development of tibiofemoral angle in Indian children is slightly different than children of other ethnicities. We recommend using age-specific values for Indian children younger than 8years of age.