Biomechanical Study of Femur after Operation of Femoral Neck Fracture in Different Movements
WANG Ying,MA Jian-xiong,BAI Hao-hao
Department of Orthopedics Research, Tianjin Hospital, Tianjin University, Tianjin 300050, China
Abstract:
Objective To explore the effects of different movements on the biomechanics of Femur after operation of femoral neck fracture, and to provide theoretical guidance for postoperative rehabilitation. Methods 30 patients with good reduction quality were randomly included in Tianjin Hospital from January 2015 to December 2017. Firstly, the femoral neck model was established by three-dimensional reconstruction method, and the quantitative parameters of reduction quality were measured. Secondly, the femoral muscle model is built by AnyBody software, and the coordinate of femoral neck model and femoral muscle model is unified and the position is matched in Geomagic Studio software. Then the femoral neck model is preprocessed, and the finite element model of femoral neck is established by Hypermesh. Finally, using AnyBody software to simulate the movements, including standing, walking, standing and squatting. The stress distribution and peak value of the femur during daily exercise were analyzed by inverse dynamics. Results The average displacement of the deepest portion of the femoral head fovea was [(9.22 ±4.42) mm], the average displacement of the center of the femoral head was [(5.32 ±22.98) mm], and the average rotational angle of the femoral head was [(19.73 ±11.61)°]. The stress peak of the femur was [(18.97±7.8) MPa] when standing, and [(66.85±36.18) MPa] during walking. In addition, during stand up, the stress peak of the femur was [(61.74±114.38) MPa], and [(1607.04±869.58) MPa] during squat down. There was significant difference among the 4 movements, except for the stand up and walking(P =0.82). Conclusion 30 cases of femoral neck included in the study all had different degrees of spatial displacement. During the four daily movements, the force on the neck of Femur is the least when standing, the next is standing and walking, and the force on the neck of femur is the greatest when squatting.
