Modified design of biotype self-locking hip joint prosthesis / 中国组织工程研究

ABSTRACT

BACKGROUND:Hip prosthesis needs to meet the good structural compatibility with femoral bone marrow cavity and the biomechanical properties of the original bone tissue. However, the difference of individual anatomical characteristics and the stress concentration in the local area after replacement directly affect postoperative combination of femoral prosthesis stem, force flow transfer and femoral reconstruction, and finaly result in aseptic loosening of hip joint in some patients. OBJECTIVE:To analyze the biomechanical characteristics of modified biotype self-locking hip prosthesis by the method of finite element analysis, and to provide the reference for the application of self-locking hip prosthesis in hip replacement. METHODS:Experimental design contained traditional biotype hip joint prosthesis group and self-locking hip joint prosthesis group. In accordance with the finite element models of self-locking hip prosthesis, 28 kinds of screw fixation were established. Three-dimensional models were generated in the Minics system. After the optimization of prosthesis, prosthesis was designed. In the Solidworks software, the femur was re-positioned and set for contacting set in Ansys to analyze the stress distribution and displacement distribution of the femoral-prosthesis-screw by Ansys. We compared the peak of stress and displacement of the femur and prosthesis, and analyzed the biomechanical stability of prosthesis. RESULTS AND CONCLUSION:(1) By using the Ansys finite element method, we analyzed the stress and displacement distribution of the femoral-prosthesis-screw. The minimum stress peak value of the femur was 15.698 MPa. The minimum stress peak value of prosthesis was 45.491 MPa. The minimum stress peak value of screw was 8.359 MPa. The minimum displacement peak value of femur was 1.125 3 mm. The minimum displacement peak value of prosthesis was 1.039 6 mm. The minimum displacement peak value of screw was 0.566 4 mm. (2) Compared with the traditional biotype hip joint prosthesis group, in 28 kinds of self-locking hip joint prostheses, the stress was minimum in the group E. The displacement was minimum in groups A-F. Regarding comprehensive stress and displacement, groups A-F were the best combination. The maximum stress of femoral-prosthesis-screw was 18.936, 59.494 and 12.382 MPa. The maximum displacement of femoral-prosthesis-screw was 1.125 3, 1.039 6 and 0.626 3 mm. (3) These findings indicated that the stress and displacement parameters of groups A-F was the best parameter combination in 28 kinds of self-locking hip joint prostheses, and it is the recommended index of researching and developing self-locking hip prosthesis.