Embed Size (px)
Citation preview
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
Simulation of Fracture Healing due to Intramedulary Nailing
Tim WehnerFrank NiemeyerLutz ClaesUlrich Simon
Institut für Unfallchirurgische Forschung und Biomechanikim Zentrum für Muskuloskelettale Forschung (zmfu)Universitätsklinikum Ulm
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
Introduction
FFIFMIFM
*Claes et al., J Orth Res 1997*Claes et al., J Orth Res 1997*Augat et al., J Orth Res 2003*Augat et al., J Orth Res 2003*Larsen et al., J Orth Res 2004*Larsen et al., J Orth Res 2004
unreamed Intramedullary Nailing
unreamed Intramedullary Nailing
high interfragmentary movements (IFM)
high interfragmentary movements (IFM)
critical for healing outcome*
critical for healing outcome*
Aim: Simulation of fracture healing process to analyze the influence of fracture type and interface distance on the healing outcome
interface interface distancedistance
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
simulation of fracture healing process
FEACalculation of local mechanical stimuli
FEACalculation of local mechanical stimuli
FE-PreprozessorChange of element stiffnessesFE-Preprozessor
Change of element stiffnesses
cbone(t), IFM(t)Prediction of healing outcome
cbone(t), IFM(t)Prediction of healing outcome
Initial conditionInitial condition
Fuzzy-Logic-ControlerRevascularisation and tissue conversionFuzzy-Logic-Controler
Revascularisation and tissue conversion
nexttime step
flexibility behaviour of BIC(FE contact model)
flexibility behaviour of BIC(FE contact model)
internal loads(muskuloskeletal model)
internal loads(muskuloskeletal model) fract. geometryfract. geometry
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
reconstruction of an in vitro tested bone implant complex (BIC)
IFMIFM
flexibility behaviour of BIC(FE contact model)
flexibility behaviour of BIC(FE contact model)
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
due to idealized fractures
boundary conditionsapplied on rigidbeam elements
determination of flexibility behaviour
IFMIFMFF
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
UUii
i⋅°= 10ϕ
specificspecific mapmap of of shearshear flexibilityflexibility behaviourbehaviour
Fshear =
0
250
500
750
1000
0 1 2 3
U_shear in mm
F_sh
ear i
n N
Phi = 0°Phi = 90°Phi = 180°Phi = 270°
direction dependent contact
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
modification of musculoskeletal model „gait 3D“ from AnyBodyrepository 6
internal loads(muskuloskeletal model)
internal loads(muskuloskeletal model)
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
modification of musculoskeletal model „gait 3D“ from AnyBodyrepository 6
yy
xxzz
-2000
-1500
-1000
-500
0
500
0 0,2 0,4 0,6 0,8 1 1,2
time in s
inte
rnal
forc
e in
N
Fx
FY
Fz
-10
-5
0
5
10
15
20
25
0 0,2 0,4 0,6 0,8 1 1,2
time in s
inte
rnal
mom
ent i
n N
Mx
My
Mz
Internal load case with AnyBody
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
fract. geometryfract. geometry
transverse fract. oblique fract. bending wedge fract.
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
simulation of fracture healing process
FEACalculation of local mechanical stimuli
FEACalculation of local mechanical stimuli
FE-PreprozessorChange of element stiffnessesFE-Preprozessor
Change of element stiffnesses
cbone(t), IFM(t)Prediction of healing outcome
cbone(t), IFM(t)Prediction of healing outcome
Initial conditionInitial condition
Fuzzy-Logic-ControlerRevascularisation and tissue conversionFuzzy-Logic-Controler
Revascularisation and tissue conversion
nexttime step
flexibility behaviour of BIC(FE contact model)
flexibility behaviour of BIC(FE contact model)
internal loads(muskuloskeletal model)
internal loads(muskuloskeletal model) fract. geometryfract. geometry
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
results of healing simulationtime course of bone concentration in the callus region
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
0
1
2
3
4
0 50 100 150 200 250
iterative step
IFM
_she
ar a
nt/p
ost i
n m
m d_nail = 11 mm
d_nail = 10 mm
d_nail = 9 mm
Influence of nail diameter (interface distance)time course of IFM, transverse fracture
dnail = 11 mm 10 mm 9 mm
bone concentration (red = 100%)
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
0
1
2
3
4
0 50 100 150 200 250
iterative step
IFM
_she
ar a
nt/p
ost i
n m
m d_nail = 11 mm
d_nail = 10 mm
d_nail = 9 mm
Influence of nail diameter (interface distance)time course of IFM, transverse fracture
dnail = 11 mm 10 mm 9 mm
bone concentration (red = 100%)
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
0
1
2
3
4
0 50 100 150 200 250
iterative step
IFM
_she
ar a
nt/p
ost i
n m
m d_nail = 11 mm
d_nail = 10 mm
d_nail = 9 mm
Influence of nail diameter (interface distance)time course of IFM, transverse fracture
dnail = 11 mm 10 mm 9 mm
bone concentration (red = 100%)
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
Influence of fracture type
0
1
2
3
4
0 50 100 150 200 250
iterative stepIF
M_s
hear
ant
/pos
t in
mm d_nail = 11 mm
d_nail = 10 mm
d_nail = 9 mm
0
1
2
3
4
0 50 100 150 200 250
iterative step
IFM
_she
ar a
nt/p
ost i
n m
m d_nail = 11 mm
d_nail = 10 mm
d_nail = 9 mm
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
limitations• Influence of cancellous bone and soft tissue on the BIC
flexibility behaviour was neglected
• Internal loads for stimulus were taken out of normal gait of a healthy human
• Only idealized fracture geometries were investigated
• Beside valcularity, no biological factors were simulated
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
discussion• Influence of the mechanical behaviour of the BIC with regard to
healing time can be analyzed
• Thin intramedullary unreamed nails (large interface distance)
and
• transverse osteotomies are critical for fracture healing processany might prolong the healing time
• method will be used for optimizing current osteosynthesisimplants in terms of minimizing the healing time
www.biomechanics.de
ANSYS ANSYS ConferenceConference & 25& 25thth CADFEM Users' Meeting 2007CADFEM Users' Meeting 2007November 21November 21stst –– 2323rdrd, 2007 , 2007 -- International Congress Center Dresden, GermanyInternational Congress Center Dresden, Germany
Acknowledgements:- biomechanical research lab, BGU Murnau
- G. v. Oldenburg, Stryker Osteosynthesis
