Imaging physeal structure and activity to evaluate physeal injury and predict limb length

About This Grant

PROJECT SUMMARY Lower limb length discrepancies and angular deformities affect approximately one-third of adults and increase the risk of osteoarthritis. Surgeries to address these conditions are common and require accurate final length prediction when planning therapy for shortening or angular deformity. . Unfortunately, current methods of prediction of final limb length rely on indirect calculations and are often imprecise. Diffusion tensor imaging (DTI) of the physis and metaphysis is a direct indicator of physeal activity, revealing critical insights such as increased tract volumes during growth spurts, changes predictive of physeal closure, and increased activity in response to growth hormone. Tractography depicts the architecture of the physeal cartilage and newly formed bone, enabling identification of abnormalities in the physes of the distal femur and proximal and distal tibia. We propose to use DTI to investigate how dysfunction in one or more physes results in shortening or malalignment and to validate DTI as a biomarker to assess differential physeal activity and predict bone length. Our specific aims evaluate the hypothesis that DTI, by informing about physeal activity, provides a more accurate prediction of growth of individual bones than current techniques. To test this hypothesis, we aim to: 1) Predict femoral and tibial length during adolescent growth in healthy girls and boys imaged serially. 2) Predict differential growth of the femurs and tibias in children with limb discrepancies between 2 and 4 cm. 3) Evaluate DTI as a predictor of growth arrests in children with distal tibial physeal fractures by determining whether DTI can predict a slowdown of growth or impending partial physeal growth arrest. We will evaluate 171 children (57 per aim) at three major pediatric institutions. Our goal is to improve the current assessment of residual growth, optimize timing and approach of surgeries for length discrepancy, and refine surgical techniques to mitigate the risk of physeal damage. This work has the potential to transform clinical practice and optimize outcomes for patients undergoing these common and complex procedures.