A Computational and Guided Strategy for PTB Transtibial Socket Design and Biomechanical Evaluation Using Finite Element Analysis

Background: The prosthetic socket is the primary component responsible for comfort, stability, and load transfer in lower limb prostheses. Traditional transtibial socket fabrication relies on plaster casting and manual rectification performed by prosthetists, producing workflows that depend heavily on clinical experience and are difficult to standardize and reproduce. Digital technologies such as three-dimensional scanning, computer-aided design, and finite element analysis (FEA) have expanded the possibilities for socket design, yet many existing approaches address geometry acquisition or biomechanical simulation without translating Patellar Tendon Bearing (PTB) clinical modification criteria into a structured digital process. This gap is especially relevant in real clinical applications where CT, MRI, and instrumented measurement systems are often unavailable, so the information that guides rectification must come from landmarks the prosthetist identifies directly on the residual limb. Methods: This study proposes a computational and digital strategy for PTB transtibial socket design that uses those prosthetist’s landmarks and PTB rectification criteria in structured geometric operations, combining structured light scanning, digital modification in Blender and MeshMixer, and anatomical reconstruction without dependence on CT or MRI. Results: We evaluated the resulting sockets through finite element analysis and compared them, on a patient-matched basis, with manually rectified sockets across three transtibial cases under static standing load. Across the three cases, the digital rectification reproduced the PTB load transfer logic of the results of the manual approach, directing load toward the patellar tendon while relieving the pressure-sensitive regions, although the two approaches did not produce the same stress magnitudes. Conclusions: The results show that a structured digital process can capture PTB modification logic while remaining usable in settings without advanced imaging. This study is a computational evaluation of how the two rectification approaches transfer load under static standing conditions. Interface contact pressure and clinical fitting were not measured, so experimental validation was not included.