Implementation of a 3d Framework for Clinical Leg Alignment Analysis and Correction Osteotomy Planning

There is an increased interest in implementing a 3D framework for leg alignment analysis in the context of deformity correction and total knee arthroplasty. However, there is variability in available and reported methods to derive axes and joint orientations from 3D bone models, and no consensus on a fundamental framework like in 2D analysis. Therefore, the purpose of this study was to develop a 3D framework for leg alignment analysis that experts can agree on and implement it in a clinical setting. A systematic review of the literature between 2006 and 2024 was performed to find reported methods to derive axes and joint orientations from 3D bone models and investigate the variability. Then, a Delphi consensus study was performed in four rounds, in which an international panel of experts evaluated statements regarding principles preserving the complexity of 3D anatomical structures that could serve as a fundamental framework. Finally, the framework was implemented in a 3D planning platform allowing multiplanar malalignment-correcting high tibial osteotomy. 93 studies were included in the systematic review, which revealed high variability in the reported methods to derive axes and joint orientations from 3D bone models. Nevertheless, underlying principles were defined that were used to develop the statements for the Delphi consensus study. 35 participants took part in the surveys of the Delphi method, and all statements eventually reached consensus (≥80% agreement). The resulting fundamental framework was implemented in a custom software package and successfully used to plan and execute a simultaneous slope and varus-correcting high tibial osteotomy. Based on a systematic review and Delphi consensus study, a structured 3D framework was successfully implemented in lower limb osteotomy planning and execution in a clinical setting. The established framework could improve the standardization of 3D clinical workflows. Future research should focus on defining a patient-specific target for alignment correction and robustly registering computer-assisted computer planning to the operating room.