Finite element analysis and clinical application of percutaneous sustentaculum tali screw fixation for Sanders type II and III calcaneal fractures

In calcaneal fractures, percutaneous screw fixation (PSF) is currently considered a promising alternative to established techniques such as the L-shape or sinus tarsi approach. The present study establishes a novel percutaneous sustentaculum tali (ST) screw fixation model for Sanders type II and type III calcaneal fractures, assessing construct stability via finite element analysis (FEA) while concurrently evaluating clinical efficacy through postoperative follow-up. This study utilized FEA, based on the Sanders III fracture line model, to compare the stability of internal implants and fracture fragments between the percutaneous ST screw fixation model, the intramedullary nail model, the locking compression plate (LCP), and minimally invasive plate (MIP), thereby evaluating the biomechanical stability of the percutaneous ST screw construct. In parallel, 23 clinical surgical cases of percutaneous ST screw fixation were included. Through postoperative follow-up, the therapeutic effect was observed to jointly verify the effectiveness of percutaneous ST fixation. Regarding the FEA, after stress loading, among the four internal fixation models, the peak von Mises stress within the calcaneus was maximal in the intramedullary nail model and minimal in the ST screw model. Regarding implant-related stresses, the LCP model exhibited the highest von Mises stress, while the percutaneous ST screw model demonstrated the lowest. In parallel, the maximal fragment displacement in every model was below the reference threshold (150 μm). Percutaneous ST screw fixation demonstrates equivalent biomechanical stability compared with the other constructs. In the clinical follow-up, both the AOFAS and MFS indicated good to excellent functional outcomes, and the low VAS values reflected minimal to no pain, collectively confirming satisfactory restoration of foot function. This study, through FEA and postoperative clinical follow-up, validates percutaneous ST screw fixation as a reliable modality for Sanders type II and III calcaneal fractures, thereby providing an evidence-based reference for calcaneal fracture management. Nevertheless, further biomechanical investigations and larger clinical series are warranted for corroboration.