组配式人工半骨盆假体重建的生物力学分析

Objective To analysis the biomechanical characteristics of the reconstructed pelvis with modular hemi-pelvie prosthesis by finite element (FE) method. Methods A subject-specific finite element model of pelvis was established. Th experiment was performed on the same cadaveric pelvis. Eight points on the surface of cortical bone was determined. Both the same load and boundary conditions were applied on the FE model and experiment. The stress by experiment (σ EXP) was calculated based on the data collected from the strain discs. Linear regression was performed with the stress predicted by FE model (σFEM) and experi-ment data to validate the FE model. A defect pelvic (with zone Ⅱ +Ⅲ in left hemi-pelvis) FE model was con-structed and assembled with the prosthesis. The stress distribution on the eontra lateral hemi-pelvis was cal-culated by the reconstructed pelvic FE model (σRS), and the results were compared with that of the normal pelvis (σNS). Also the comparison was clone at the resection level of the affected hemi-pelvis between normal pelvic FE model (σNR) and reconstructed model (σRR) both on medial and lateral cortical bone of the pelvis. Structural analysis was performed on the whole set of implant. Results FE predictions were strongly correlated with experimental results (R2=0.87). No significant difference was found between the σRS and σNS (t=1.81, P=0.08). Regarding to the stress distribution at lilac resection level, no difference was found between σNR and σRR on the medial side (t=0.47, P=0.65). However, on the lateral side, σRR were signifi-cantly higher than the σNR (t=2.78, P=0.02). The peak stress of the prosthesis was about 183 MPa located at the conjunction of the acetabulum and the iliac fixation part. The main load conduction path on the prosthe-sis was at the posterior side of column portion part of the iliac fixation. Conclusion Reconstruction with modular hemi-pelvic prosthesis could recover the pelvic biomechanics with rational mechanical design.

Biomechanical analysis of pelvic reconstruction with modular hemi-pelvic prosthesis