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

Objectives 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. Methods Database of radiographs between January 2011 and December 2019 was searched. Full-length standing radiographs of patients younger than 16 years 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. Results Analysis of 221 lower limbs of 177 children is presented. There were 103 (58.2%) boys and 74 (41.8%) girls. Mean age was 8 years, 6 months (range: 2 years, 1 month to 15 years, 11 months). The mean mLDFA remained constant between 87 degrees and 88 degrees after the age of 5 years. The mean MPTA remained around 88 degrees after 8 years of age. The mean MAD remained within 4 mm of the midpoint of the knee after the age of 8 years. The adult value of TFA was achieved after 8 years of age. The mLDFA, MPTA, and mLPFA are significant predictors of change in the TFA. Conclusion 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 8 years of age.