Abstract:

BACKGROUND: At present, the finite element analysis of the pelvic biomechanics is mainly on the normal and post-traumatic pelvis. However, the three-dimensional finite element analysis of the pelvic biomechanics following malignant tumor resection and reconstruction of pelvic ring defects with modular hemipelvic prosthesis replacement is rare.
OBJECTIVE: To research and analyze the stress distribution in a standing position about the normal pelvis, postoperative contralateral pelvic and modular hemipelvic prosthesis replacement.
METHODS: First, the original digital imaging and communications standard data of the pelvis in patients with hemipelvic resection and modular hemipelvic prosthesis replacement were obtained by thin-layer CT scanning, and then the data were transferred into the Mimics8.1 software to set up three-dimensional solid model. The solid model was established by Abaqus6.7-1 analysis software. By means of the normal pelvis and after modular hemipelvic prosthesis replacement, the three-dimensional finite element models of the pelvis were set up respectively. The stress in different standing positions, including two legs standing and one leg standing, was loaded in finite element models and the results in finite element models were analyzed.
RESULTS AND CONCLUSION: In the kinds of models, the difference of contralateral pelvic stress value was small under the same load in different standing positions. The maximum stress of modular hemipelvic prosthesis in the ipsilateral pelvic at different standing positions appeared on the inner wall of connector bar between CS spinal fixation at the top of acetabular cup and acetabular cup. It is much lower than the fatigue strength of connector bar. The stress distribution of the pelvic at different standing positions after prosthesis replacement was basically consistent with the normal pelvis. ①It demonstrates that the effect of modular hemipelvic prosthesis replacement on contralateral pelvis is less. ②Modular hemipelvic prosthesis has good security at different standing positions. ③The pelvis after modular hemipelvic prosthesis reconstruction is consistent with the normal laws of human biomechanics, and has a good biomechanical compatibility.