Chinese Journal of Tissue Engineering Research ›› 2014, Vol. 18 ›› Issue (22): 3517-3522.doi: 10.3969/j.issn.2095-4344.2014.22.013

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Finite element analysis of screw layout of locking plate for treating the distal femur fracture

Lin Zhen-en, Xie Dan, Zhang Sen   

  1. Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou 350007, Fujian Province, China
  • Revised:2014-03-19 Online:2014-05-28 Published:2014-05-28
  • About author:Lin Zhen-en, Attending physician, Fuzhou Second Hospital Affiliated to Xiamen University, Fuzhou 350007, Fujian Province, China
  • Supported by:

    the Fuzhou Municipal Science and Technology Project, No. 2012-S-155-9

Abstract:

BACKGROUND: Distal femoral fractures mainly used distal femoral locking plate as internal fixation. The failure of internal fixation has been frequently reported. The distribution of steel screws was controversial in the clinic. Whether the distribution of screws was associated with the failure of internal fixation lacks of experimental evidence on mechanics.

OBJECTIVE: To investigate the screw layout of locking plates for treating the distal femoral fracture.
METHODS: By using ANSYS software modeling, fractures and plate models were established. Four screws were fixed on the proximal and distal ends of fracture. 128 kinds of screw layout were designed. Stress and fracture displacement of different screws and plates were analyzed. Screw holes 1 and 6 fixed single and double cortex groups were analyzed using one-way analysis of variance. Screw hole 5 fixed single and double cortex groups and no screw group were analyzed using one-way analysis of variance.
RESULTS AND CONCLUSION: In the distribution of 128 kinds of screws, maximum stress of the first hole was “-2 distribution group” (-2 means hole 2 without screw), and minimum stress distribution was “-4 distribution group” (-4 means hole 4 without screw). Biggest stress distribution of fifth hole was “-4 distribution group”, and  minimum stress distribution was “-3 distribution group” (-3 means hole 3 without screw). The distribution of the maximum stress in the screw hole 6 was “-4 distribution group”, and minimum stress distribution was “-2 distribution group”. The distribution of maximum stress in the plate was “-4 distribution group”, and minimum stress distribution was “-5 distribution group” (-5 means hole 5 without screw). The distribution of the maximum displacement was “-5 distribution group”, minimum distribution was “-3 distribution group”. Of the 128 kinds of screws, no significant difference was detected in screws, plate stress and fracture displacement in the first and sixth holes of single and double cortex distributed groups. Fracture displacement in no screw group was bigger than in hole 5 single and double cortex groups (P < 0.05). No significant difference was detectable in screw stress and plate stress among the three groups. Results indicated that the proximal first hole and second hole in the plate should be fixed. Two holes were close to the proximal end of the fracture (for example holes 4 and 5). The hole 4 should be fixed. Whether the hole 5 should be fixed was judged according to the stability of the fracture. The middle hole could not be fixed. The hole 6 was recommended to be fixed. ANSYS analysis is an effective orthopedic clinical research method.

中国组织工程研究杂志出版内容重点:人工关节;骨植入物;脊柱骨折;内固定;数字化骨科;组织工程


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Key words: femoral fractures, finite element analysis, internal fixators, biomechanics

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