title: Femur performed better than tibia in autologous transplantation during hemipelvis reconstruction.
abstract: BACKGROUND
  Pelvic reconstruction after hemipelvectomy can greatly improve the weight-bearing stability of the supporting skeleton and improve patients' quality of life. Although an autograft can be used to reconstruct pelvic defects, the most suitable choice of autograft, i.e., the use of either femur or tibia, has not been determined. We aimed to analyze the mechanical stresses of a pelvic ring reconstructed using femur or tibia after hemipelvectomy using finite element (FE) analysis.
  
  
  METHODS
  FE models of normal and reconstructed pelvis were established based on computed tomography images, and the stress distributions were analyzed under physiological loading from 0 to 500 N in both intact and restored pelvic models using femur or tibia.
  
  
  RESULTS
  The vertical displacement of the intact pelvis was less than that of reconstructed pelvis, but there was no significant difference between the two reconstructed models. In FE analysis, the stress distribution of the intact pelvic model was bilaterally symmetric and the maximum stresses were located at the sacroiliac joint, arcuate line, ischiatic ramus, and ischial tuberosity. The maximum stress in each part of the reconstructed pelvis greatly exceeded that of the intact model. The maximum von Mises stress of the femur was 13.9 MPa, and that of the tibia was 6.41 MPa. However, the stress distribution was different in the two types of reconstructed pelvises. The tibial reconstruction model induced concentrated stress on the tibia shaft making it more vulnerable to fracture. The maximum stress on the femur was concentrated on the connections between the femur and the screws.
  
  
  CONCLUSIONS
  From a biomechanical point of view, the reconstruction of hemipelvic defects with femur is a better choice.
authors.affiliation: Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai, 200065, China. meijiong@163.com.
authors.forename: Jiong
authors.initials: J
authors.lastname: Mei
authors.forename: Ming
authors.initials: M
authors.lastname: Ni
authors.forename: You-Shui
authors.initials: YS
authors.lastname: Gao
authors.forename: Zhi-Yuan
authors.initials: ZY
authors.lastname: Wang
mesh_terms: D000368:Aged; D005260:Female; D005269:Femur / Q000601:surgery*; D020342:Finite Element Analysis; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D010384:Pelvic Bones / Q000601:surgery*; D011379:Prognosis; D019736:Prostheses and Implants; D019651:Plastic Surgery Procedures; D013314:Stress, Mechanical; D013977:Tibia / Q000601:surgery*; D014182:Transplantation, Autologous; D016474:Weight-Bearing / Q000502:physiology