Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor
ABSTRACT To evaluate the mechanical stress and elastic deformation exercised in the thread/shaft transition of Schanz screws in assemblies with different screw anchorage distances in the entrance to the bone cortex, through the distribution and location of tension in the samples. An analysis of 3D f...
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| Format: | Article |
| Language: | English |
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Sociedade Brasileira de Ortopedia e Traumatologia
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| Series: | Revista Brasileira de Ortopedia |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-36162017000400396&lng=en&tlng=en |
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| author | Vincenzo Giordano Alexandre Leme Godoy-Santos William Dias Belangero Robinson Esteves Santos Pires Pedro José Labronici Hilton Augusto Koch |
| author_facet | Vincenzo Giordano Alexandre Leme Godoy-Santos William Dias Belangero Robinson Esteves Santos Pires Pedro José Labronici Hilton Augusto Koch |
| author_sort | Vincenzo Giordano |
| collection | DOAJ |
| description | ABSTRACT To evaluate the mechanical stress and elastic deformation exercised in the thread/shaft transition of Schanz screws in assemblies with different screw anchorage distances in the entrance to the bone cortex, through the distribution and location of tension in the samples. An analysis of 3D finite elements was performed to evaluate the distribution of the equivalent stress (triple stress state) in a Schanz screw fixed bicortically and orthogonally to a tubular bone, using two mounting patterns: (1) thread/shaft transition located 20 mm from the anchorage of the Schanz screws in the entrance to the bone cortex and (2) thread/shaft transition located 3 mm from the anchorage of the Schanz screws in entrance to the bone cortex. The simulations were performed maintaining the same direction of loading and the same distance from the force vector in relation to the center of the hypothetical bone. The load applied, its direction, and the distance to the center of the bone were constant during the simulations in order to maintain the moment of flexion equally constant. The present calculations demonstrated linear behavior during the experiment. It was found that the model with a distance of 20 mm between the Schanz screws anchorage in the entrance to the bone cortex and the thread/shaft transition reduces the risk of breakage or fatigue of the material during the application of constant static loads; in this model, the maximum forces observed were higher (350 MPa). The distance between the Schanz screws anchorage at the entrance to the bone cortex and the smooth thread/shaft transition of the screws used in a femoral distractor during acute distraction of a fracture must be farther from the entrance to the bone cortex, allowing greater degree of elastic deformation of the material, lower mechanical stress in the thread/shaft transition, and minimized breakage or fatigue. The suggested distance is 20 mm. |
| first_indexed | 2024-03-08T08:27:07Z |
| format | Article |
| id | doaj.art-14c0f317d5464610b0faeebf3a93fff4 |
| institution | Directory Open Access Journal |
| issn | 1982-4378 |
| language | English |
| last_indexed | 2024-03-08T08:27:07Z |
| publisher | Sociedade Brasileira de Ortopedia e Traumatologia |
| record_format | Article |
| series | Revista Brasileira de Ortopedia |
| spelling | doaj.art-14c0f317d5464610b0faeebf3a93fff42024-02-02T04:28:47ZengSociedade Brasileira de Ortopedia e TraumatologiaRevista Brasileira de Ortopedia1982-437852439640110.1016/j.rboe.2017.07.003S0102-36162017000400396Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractorVincenzo GiordanoAlexandre Leme Godoy-SantosWilliam Dias BelangeroRobinson Esteves Santos PiresPedro José LabroniciHilton Augusto KochABSTRACT To evaluate the mechanical stress and elastic deformation exercised in the thread/shaft transition of Schanz screws in assemblies with different screw anchorage distances in the entrance to the bone cortex, through the distribution and location of tension in the samples. An analysis of 3D finite elements was performed to evaluate the distribution of the equivalent stress (triple stress state) in a Schanz screw fixed bicortically and orthogonally to a tubular bone, using two mounting patterns: (1) thread/shaft transition located 20 mm from the anchorage of the Schanz screws in the entrance to the bone cortex and (2) thread/shaft transition located 3 mm from the anchorage of the Schanz screws in entrance to the bone cortex. The simulations were performed maintaining the same direction of loading and the same distance from the force vector in relation to the center of the hypothetical bone. The load applied, its direction, and the distance to the center of the bone were constant during the simulations in order to maintain the moment of flexion equally constant. The present calculations demonstrated linear behavior during the experiment. It was found that the model with a distance of 20 mm between the Schanz screws anchorage in the entrance to the bone cortex and the thread/shaft transition reduces the risk of breakage or fatigue of the material during the application of constant static loads; in this model, the maximum forces observed were higher (350 MPa). The distance between the Schanz screws anchorage at the entrance to the bone cortex and the smooth thread/shaft transition of the screws used in a femoral distractor during acute distraction of a fracture must be farther from the entrance to the bone cortex, allowing greater degree of elastic deformation of the material, lower mechanical stress in the thread/shaft transition, and minimized breakage or fatigue. The suggested distance is 20 mm.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-36162017000400396&lng=en&tlng=enFinite element analysisBone nailsFemoral fracturesExternal fixatorsTreatment outcome |
| spellingShingle | Vincenzo Giordano Alexandre Leme Godoy-Santos William Dias Belangero Robinson Esteves Santos Pires Pedro José Labronici Hilton Augusto Koch Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor Revista Brasileira de Ortopedia Finite element analysis Bone nails Femoral fractures External fixators Treatment outcome |
| title | Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor |
| title_full | Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor |
| title_fullStr | Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor |
| title_full_unstemmed | Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor |
| title_short | Finite element analysis of the equivalent stress distribution in Schanz screws during the use of a femoral fracture distractor |
| title_sort | finite element analysis of the equivalent stress distribution in schanz screws during the use of a femoral fracture distractor |
| topic | Finite element analysis Bone nails Femoral fractures External fixators Treatment outcome |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-36162017000400396&lng=en&tlng=en |
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