. 2009, 27(0920): 22-26.
After hindquarter amputation, the pelvis reconstruction using abandoned autogenous lower-extremity long bones is an effective biological reconstruction method. However, the bio- mechanical effects of this reconstruction have never been well studied. The objective of the present study is to estimate the feasibility of the operation using the finite element simulation, and to analyze the stress distributions before and after the reconstruction under sitting posture. Two operative schemes, the ischiadic tuberosity replacement with condyles of femur and tibial plateau, respectively, are considered. With additionally the intact model, three finite element models are constructed, and the intact model is validated through stress and displacement measurements in a cadaver specimen. Normal sitting posture is considered in the simulations of these models, and von Mises stresses are used as indexes in comparison. The stress distributions are found to be significantly different before and after the reconstructions. In the model of condyles of femur reconstruction, severe stresses are mainly distributed at the contact surface between femur and the facies auricularis of the left sacral bone, the right iliosacral articulation, and the left long bar. In the model of tibial plateau reconstruction, the peak stresses in the remained iliac and sacral bones, the bridging bone, and long bar are greater than those in the model of condyles of femur reconstruction. Compared with the peak stress in the grafted femur of the latter model, the peak stress in the tibial of the former model is distributed at the shaft of bone, with a broader distribution area. From the view point of biomechanics, the reconstruction with condyles of femur shows a better performance. In the operation design, the diameter of long bars should be appropriately great, and the rigidity of the bars should be reduced as long as a sufficient strength is allowed.
