Abstract
Background
Large segmental bone defects in the distal femur, caused by high-energy trauma, tumor resection, and debridement of osteomyelitis, pose significant clinical challenges. The advent of 3D-printed microporous titanium prostheses offers new solutions for these complex reconstructions.
Objective
To investigate the biomechanical distribution and stability of three different 3D-printed microporous titanium prosthesis designs and fixation methods for reconstructing large segmental bone defects in the distal femur.
Methods
Three prosthesis models were developed: single-steel plate, double-steel plate, and intramedullary nail groups. Finite element analysis (FEA) was performed to simulate stress distribution and displacement understanding (0°), semi-squatting (90°), and squatting (150°) postures. The biomechanical properties, including maximum stress and displacement, were analyzed to evaluate the stability and safety of each prosthesis design.
Results
The single-steel-plate group showed higher maximum stress and displacement, particularly under semi-squatting and squatting postures, indicating potential instability. The double-steel-plate group exhibited lower stress and displacement, providing better stability than the single-steel-plate group. The intramedullary nail group demonstrated the most favorable biomechanical performance, with the lowest maximum stress and even stress distribution, enhancing mechanical stability and reducing stress shielding.
Conclusion
For large segmental defects in the distal femur, intramedullary nail fixation is recommended for superior stability and biomechanical performance. Single—or double-steel-plate prostheses are suggested for patients with severe osteoporosis or narrow medullary cavities. These findings provide valuable insights into selecting appropriate fixation methods based on individual patient conditions to achieve optimal biomechanical outcomes.