title: A 3D finite element model to investigate prosthetic interface stresses of different posterior tibial slope.
abstract: OBJECTIVE
  Posterior tibial slope that is created during proximal tibial resection in total knee arthroplasty has emerged as an important factor in the mechanics of the knee joint and the surgical outcome. But the ideal degree of posterior tibial slope for recovery of the knee joint function and preventions of complications remains controversial and should vary in different racial groups. The objective of this paper is to investigate the effects of posterior tibial slope on contact stresses in the tibial polyethylene component of total knee prostheses.
  
  
  METHODS
  Three-dimensional finite element analysis was used to calculate contact stresses in tibial polyethylene component of total knee prostheses subjected to a compressive load. The 3D finite element model of total knee prosthesis was constructed from the images produced by 3D scanning technology. Stresses in tibial polyethylene component were calculated with four different posterior tibial slopes (0°, 3°, 6° and 9°).
  
  
  RESULTS
  The 3D finite element model of total knee prosthesis we presented was well validated. We found that the stress distribution in the polythene as evaluated by the distributions of the von Mises stress, the maximum principle stress, the minimum principle stress and the Cpress were more uniform with 3° and 6° posterior tibial slopes than with 0° and 9° posterior tibial slopes. Moreover, the peaks of the above stresses and trends of changes with increasing degree of knee flexion were more ideal with 3° and 6° posterior slopes.
  
  
  CONCLUSIONS
  The results suggested that the tibial component inclination might be favourable to 7°-10° so far as the stress distribution is concerned. The range of the tibial component inclination also can decrease the wear of polyethylene. Chinese posterior tibial slope is bigger than in the West, and the current domestic use of prostheses is imported from the West, so their demands to tilt back bone cutting can lead to shorten the service life of prostheses; this experiment result is of important clinical significance, guiding orthopaedic surgeon after the best angle to cut bone.
authors: Department of Orthopaedic, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 DongFang Road, Shanghai, 200127, China.
authors: Yi
authors: Y
authors: Shen
authors: Department of Orthopaedic, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 DongFang Road, Shanghai, 200127, China. leexm1123@hotmail.com.
authors: Xiaomiao
authors: X
authors: Li
authors: Department of Orthopaedic, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 DongFang Road, Shanghai, 200127, China.
authors: Xiaodong
authors: X
authors: Fu
authors: Department of Orthopaedic, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, 1630 DongFang Road, Shanghai, 200127, China.
authors: Weili
authors: W
authors: Wang
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D001672:Biocompatible Materials; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000503:physiopathology / Q000601:surgery*; D007720:Knee Prosthesis; D020959:Polyethylene; D011475:Prosthesis Failure; D013314:Stress, Mechanical; D013977:Tibia / Q000503:physiopathology / Q000601:surgery*
chemical_list: D001672:Biocompatible Materials; D020959:Polyethylene
keywords: Finite element analysis; Knee prosthesis; Polyethylene; Posterior tibial slope; Total knee arthroplasty