Dependence of the 8-plate position inhemiepiphysiodesis on the X-ray parameters of the epimetaphyseal bone junction

Abstract

Introduction. To correct axial deformities in children at the knee joint level, the method of “guided growth” using the 8-plate is applied. Despite the widespread use of this method, the toolkit for its implementation was developed mainly for patients with idiopathic deformities and does not take into account the features of the epimetaphyseal bone junction in children with skeletal dysplasias. Aim. To develop X-ray criteria that characterize anatomical features of the epimetaphyseal region of the bone to predict possible difficulties associated with the position of the metal structure in hemiepiphysiodesis. Materials and methods. We developed calculations of the X-ray parameters of the epimetaphyseal junction of the bone (angle of the epimetaphyseal junction and index of the epimetaphyseal junction) in 58 patients (107 lower limbs) with axial deformities in the frontal plane at the knee level in skeletal dysplasias (main group). The control group included 50 children (67 lower limbs) with identical deformities but without a primary lesion of the growth plate in which similar calculations of the X-ray parameters were performed. In stage I of the study, all patients were admitted to the Department of the Turner Research Institute for Children’s Orthopedics for temporary hemiepiphysiodesis using the 8-plate to correct axial deformities of the lower extremities at the knee joint level. In stage 2, the metal structure position was evaluated after the operative treatment that adhered the plate to the bone metaphysis. A total of 255 plates were fixed: the hemiepiphysiodesis of the femur was performed in 138 cases and of the tibia in 117. Pearson correlation coefficient analysis was performed by using IBM SPSS Statistics version 23 software. Results. Among the patients who underwent surgical interventions using the method of guided growth, incomplete adherence of the plate to the bone was observed in 43 (17.3%) of 255 fixed plates because of the anatomical features of the epimetaphyseal region and more often in patients with skeletal dysplasias. Conclusion. We developed X-ray criteria for the angle of the epimetaphyseal junction and the index of the epimetaphyseal junction that are recommended for prediction of the position of metal structures.