Biomechanical Evaluation of Patient-Specific Titanium Fixation Systems for Segmental Le Fort I Osteotomy: A Finite Element Analysis.

Patient-specific Ti-6Al-4V fixation systems are increasingly used to stabilise the maxilla following segmental Le Fort I osteotomy; however, the biomechanical responses of complete locking and non-locking patient-specific fixation configurations remain insufficiently characterised. In this study, two patient-specific plate designs (a standard design and a reduced, minimally invasive design) were analysed by linear-elastic finite element analysis, each with locking and non-locking screws. Because they were developed for different indications and evaluated in distinct patient-specific anatomical models, between-model comparisons were considered descriptive. Vertical forces of 97.6, 206.9, and 257.0 N were applied bilaterally to the incisor and premolar regions, and the equivalent von Mises stress and total displacement were evaluated in the bone, plates, and screws. All results scaled linearly with load. Within the standard model, the locking configuration exhibited slightly greater bone, plate, and screw displacement than the corresponding non-locking configuration. Within the reduced model, it exhibited lower maximum bone, plate, and screw displacement by 16.4%, 19.2%, and 16.3%, respectively. Solver-reported local stress maxima were concentrated at the screw-head/plate-hole transition; because these isolated peaks were contact- and mesh-sensitive, they were not used to quantify relative screw loading or predict yielding. The modelled locking and non-locking fixation configurations therefore exhibited different, model-dependent displacement patterns. Further controlled simulations and experimental validation are required to determine the clinical relevance of these findings.