Biomechanical Study of Anatomical Reconstruction of Posterior Wall of the Acetabulum

Objective: To design a new posterior wall reconstruction method and to elucidate its biomechanical foundation. Methods: The experiment consists of two parts, one is to study the stability of the new method, the other is to research the fitness of the femoral head and the reconstructed acetabulum. Six fresh pelvis and femur specimens were used, the experimental group consists of the left sides, and the control group consists of the right sides. After the defects of the posterior wall were made, the defects were anatomical reconstructed with the harvested ilium by ATMS made of SMA in the experimental group, whereas the acetabular fragments were replaced to the defect sites and fixated by the plates and screws in the control group. A jig which can be adjusted in multiple directions was mad, and the specimens were loaded from 100N to 500N in three status, flexion, extension, and erection, the displacements in latitude and longitude of two groups were compared, and the stability of reconstruction of posterior wall of the acetabulum was analyzed. After that, two groups were loaded to 1000N in erection status, the pressure-sensitive slices were used to calculate the contact area, the mean pressure and maximum pressure of anterior wall, superior aspect and posterior wall of the acetabulum, and to analyzed the fitness of femoral head and the acetabulum as well as the stress distribution. Results: There was no significant difference of displacement between the two groups in the different status with different loads. And there was no significant difference between two groups in the contact area, mean pressure and maximum pressure of every part of acetabulum. Conclusion: Anatomical reconstruction of posterior wall of the acetabulum with ATMS had good stability and good fitness and stress distribution of the femoral head and the reconstructed acetabulum.