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Modern Implants in orthopaedic TraumaModern Implants in orthopaedic Trauma
Arndt P Schulz, MD, MRCS (Glasgow)Arndt P Schulz, MD, MRCS (Glasgow)
University Hospital LUniversity Hospital Lbeck, Dept Trauma and Orthopaedicsbeck, Dept Trauma and Orthopaedics
Klaus Seide, MD, PhDKlaus Seide, MD, PhD
BG Trauma Hospital Hamburg, Biomechanical LaboratoryBG Trauma Hospital Hamburg, Biomechanical Laboratory
Masters Programme
Biomedical Engineering
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Orthopedic surgeons have aOrthopedic surgeons have abroad variety of implantsbroad variety of implants
for external and internalfor external and internalstabilisation of fracturesstabilisation of fractures
and luxationsand luxations
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External fixatorExternal fixator
ImplantsImplants
(e.g for the distal femur)(e.g for the distal femur)
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ScrewsScrews
Implants
(e.g for the distal femur)
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patient, female, 37 y.:patient, female, 37 y.: distal femoral fracture type B2distal femoral fracture type B2
caused by a fall down the stairs ; treated with 3 screwscaused by a fall down the stairs ; treated with 3 screws
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ImplantsImplants(e.g for the distal femur)(e.g for the distal femur)
Conventional plate systems:Conventional plate systems:
Condylar plate (so
called Burri-plate)
95 angular blade plate
Dynamic condylar screw(DCS)
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patient female 60 y.:patient female 60 y.: distal femoral fracturedistal femoral fracture
type A1 caused by a simple fall due to osteoporosis;type A1 caused by a simple fall due to osteoporosis;
treated with a DCStreated with a DCS
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IntramedullarIntramedullarnailsnails
ImplantsImplants
(e.g for the distal femur)(e.g for the distal femur)
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patient, male, 40 y.:patient, male, 40 y.:A1 distal femoral fracture typeA1 distal femoral fracture type
A1 caused by a car accident ; treated with anA1 caused by a car accident ; treated with an
intramedullary nailintramedullary nail
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Angular stable internal fixators withAngular stable internal fixators with
locked screwslocked screws
ImplantsImplants
(e.g for the distal femur)(e.g for the distal femur)
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patient, female, 18 y.:patient, female, 18 y.: distal femoral fracture typedistal femoral fracture type
C3 caused by a car accident ; treated with an angular stableC3 caused by a car accident ; treated with an angular stable
internal fixatorinternal fixator
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.and now let.and now lets have as have a
closer look on internalcloser look on internal
fixators or implants withfixators or implants withlocked screws or angularlocked screws or angular
stable implantsstable implants
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How to defineHow to define
angular stability ?angular stability ?
strong, longlasting butstrong, longlasting but
reversible union ofreversible union ofscrews and longitudinalscrews and longitudinal
stabilisator (plate, nailstabilisator (plate, nail
or external fixator rod)or external fixator rod)
(Wolter 1985)(Wolter 1985)
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Biomechanical principle IBiomechanical principle I
conventional plateconventional plate--
osteosynthesisosteosynthesisinternal plate fixatorinternal plate fixator
Seide et al. 1999
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Biomechanical principle IIBiomechanical principle II
conventionalconventionalplateplate--
osteosynthesisosteosynthesis
internal plateinternal plate
fixatorfixator
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Why do we need internal fixators?Why do we need internal fixators?
1.1. Higher and first of allHigher and first of alllongerlasting stability.longerlasting stability.
2.2. More independence fromMore independence frombone quality than inbone quality than inconventional plating.conventional plating.
3.3. Biological reasons. TheBiological reasons. Theblood supply of the boneblood supply of the boneby the periostium is lessby the periostium is lessdisturbed due to adisturbed due to adiminished pressure ondiminished pressure onthe bone by the plate.the bone by the plate.
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Different ImplantsDifferent ImplantsLess invasive stabilisation System (LISS)Less invasive stabilisation System (LISS)
Unidirectional,monocortical screws
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Multidirectional internal plate fixatorsMultidirectional internal plate fixatorsPressurePressure--PlatePlate--FixatorFixator
(PPF)(PPF) Titanium Internal-Fixateur (TiFix)
cervical, thoracical
and lumbar spine
femur
1st generation; distal
femur, tibia
2nd generation;the rest of thebody
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First Solution in 1931 by DrFirst Solution in 1931 by Dr
Reinhold/ ParisReinhold/ Paris
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First modern solution to produce anFirst modern solution to produce an
angular stable screwangular stable screw--plate interfaceplate interfaceMultidirectional internal fixator for the thoracic andMultidirectional internal fixator for the thoracic and
lumbar spine 1985lumbar spine 1985 -- Pressure plate principlePressure plate principle
Angular stability by locking the head ofAngular stability by locking the head ofthe screw in the plate hole withthe screw in the plate hole with
Stabilisation of a fracture of theStabilisation of a fracture of the
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Stabilisation of a fracture of theStabilisation of a fracture of the
1. lumbar vertebral body by a PPF1. lumbar vertebral body by a PPF
PressurePressure-PlatePlate-Fixator (PPF)Fixator (PPF)
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PressurePressure--PlatePlate--Fixator (PPF)Fixator (PPF)
for the femurfor the femur
`83 `85
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First patient
treated with aPPF*1941injured in 1983
83 85
`87 `93
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Bony consolidation inBony consolidation in
9/19939/1993
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l h
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Minimal invasive osteosynthesisMinimal invasive osteosynthesis
of the femur by a PPFof the femur by a PPF
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Plate:Plate: softersofter Material (e.g. titanium grade 1 )Material (e.g. titanium grade 1 )
Screw:Screw: harderharder material (e.g. titanium grade 4material (e.g. titanium grade 4or 5, titanium alloy) 1992or 5, titanium alloy) 1992
Angular stability by material reshapingAngular stability by material reshaping
Second solution to produce aSecond solution to produce a
locked screwlocked screw--plate interfaceplate interface
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TiFix 1TiFix 1stst GenerationGeneration
Thread-miller
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TiFix 1TiFix 1stst generationgeneration
The angleThe anglebetween screwbetween screw
and plate can beand plate can be
choosen freely upchoosen freely upto 45to 45 to eachto each
direction !direction !
TiFix 2TiFix 2ndnd GenerationGeneration
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TiFix 2TiFix 2ndnd GenerationGeneration
liplip--constructionconstruction
No threadNo thread--millermiller
needed!needed!
History of the development of multiHistory of the development of multi--
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History of the development of multiHistory of the development of multi
directional internal plate fixatorsdirectional internal plate fixators1985 PPF lumbar an1985 PPF lumbar and thoracicd thoracic
spinespine1991 PPF cervical spine1993 PPF femur
1997 TiFix tibia1998 TiFix calcaneus and
distal femur1999 TiFix humeral head,
forearm and tibial head
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First problemFirst problem
d bl
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Second problemSecond problem
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Solution?Solution?
Unilateral osteosynthesis ofUnilateral osteosynthesis of
tibial head by angular stabletibial head by angular stable
butress platebutress plate
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Biomechanical Study designBiomechanical Study design
Comparison of unilateral osteosynthesis of tibialComparison of unilateral osteosynthesis of tibial
head fractures by butress plate in angular stablehead fractures by butress plate in angular stable
and conventional technique in fresh humanand conventional technique in fresh humancadaveric tibial heads by biomechanical testing oncadaveric tibial heads by biomechanical testing on
a servohydraulic material test machine.a servohydraulic material test machine.
The technique of plating (angular stable orThe technique of plating (angular stable or
conventional) was the only variable.conventional) was the only variable.
M t i lM t i l
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MaterialMaterial
5 paarige humane Tibiakopfpr5 paarige humane Tibiakopfprparate aufparate auf45mm gek45mm gekrzt.rzt.
5 paired fresh human cadaveric tibialheads cut down to a length of 45millimeters
Measurement of bone densityMeasurement of bone density
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Measurement of bone densityMeasurement of bone density
by computer tomographyby computer tomography
European spine
phantom
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M t i l t ti hiM t i l t ti hi
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Material testing machineMaterial testing machine
Biaxial, servohydraulicBiaxial, servohydraulic
material testingmaterial testingmachine MTS Typmachine MTS Typ
Bionix 858.2Bionix 858.2
St d di d tiStandardized preparation
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Standardized preparationStandardized preparation
XX t ll d t th it ll d t th i
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XX--ray controlled osteosynthesisray controlled osteosynthesis
Testing assemblyTesting assembly
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Testing assemblyTesting assembly
Tibial head
Femoral partof a knee
prothesis
LVDT
plate
LVDT
link joint
X-Y-table
Testing protocolTesting protocol
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Testing protocolTesting protocol
preload 10Npreload 10N
sinus shaped, cyclic, forcesinus shaped, cyclic, force--induced load,induced load,frequence 4 Hzfrequence 4 Hz
initial axial load 100 Ninitial axial load 100 N increase of load by 50 N every 2000increase of load by 50 N every 2000
cycles until failure of the construct or 700 Ncycles until failure of the construct or 700 Nareare reached (maximum 26000 cycles)reached (maximum 26000 cycles)
ResultsResults II
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ResultsResults II
failurefailure (at load in N )(at load in N )numbernumber bone densitybone density
(mg HA/cm(mg HA/cm)) angular stableangular stable conventionalconventional11 146.8146.8 600600 350350
22 63.163.1 >700>700 300300
33 78.178.1 550550 20020044 60.460.4 600600 400400
55 118.7118.7 650650 450450
medianmedian 600600 350350
minmin 550550 200200
maxmax >700>700 450450
Results IIResults II
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Results IIResults IIvarus motion at 100Nvarus motion at 100N (mm)(mm) offset at 100Noffset at 100N (mm)(mm)numbernumber
angular stableangular stable conventionalconventional angular stableangular stable conventionalconventional
11 0.1130.113 0.1390.139 0.4440.444 0.4240.42422 0.0030.003 0.0870.087 0.2690.269 0.4250.425
33 0.1460.146 0.6310.631 0.3310.331 1.2071.207
44 0.2530.253 0.2690.269 0.2940.294 0.2680.26855 0.060.06 0.1390.139 0.2010.201 0.3500.350
medianmedian 0.1130.113 0.1390.139 0.2940.294 0.4240.424
minmin 0.0030.003 0.0870.087 0.2010.201 0.2680.268
maxmax 0.2530.253 0.6310.631 0.4440.444 1.2071.207
SummarySummary
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SummarySummary
The angular stable construct showed in
every single test a significant higherstability in comparison to the conventionalconstruct (p < 0,05)
The increase of stability concerning varus
motion and offset reached up to 500%.
A loosening of the angular stable screw-plate interface was seen in no case
And in the FutureAnd in the Future ??
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And in the FutureAnd in the Future??
Routine Load Measurements ininternal Fixator Systems
Monitoring of Fracture Healing
Optimisation of postoperative Treatment
Concept
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Locked Implant
DMS Sensors
Microelektronic/Telemetry
Encapsulation
Concept
Telemetry
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Telemetry
RF-Interface
C basedcontrol unit
Energy
Data
Disla
ApplicationPC with custom-designed
software
C basedtransponder
Readout circuit
Sensor
Pow
er
Readercoil
Transpondercoil
External Electronics Implantable System
Transponder with Sensor Interface
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Transponder with Sensor-Interface
Implants for Tibia and Femur
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Implants for Tibia and Femur
Readout
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Readout
Biomechanic in vitro testing
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Biomechanic in vitro testing
Biegung senkrecht zur Plattenebene
unter simulierten Frakturbedingungen
-300
-200
-100
0
100
200
300
0 100 200 300 400 500 600 700 800 900
Newton
V/V
F4
F5
F6
F7
F8
F9
F10
F11
F12
F13
F14F15
F16
F17
F18
F19
F20
F21
F22
F23
F24
F25
E1
E5
E6
In-vivo testing in sheep
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In-vivo testing in sheep
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Korrelation Fixateurbelastung vs. Kraft
(8 Kraftzyklen)y = 2,4677x + 35,171
R2
= 0,9532
Steifigkeit: 0,41 N/(m/m)
0,0
25,0
50,0
75,0
100,0
125,0
150,0
175,0
200,0
0,0 5,0 10,0 15,0 20,0 25,0 30,0 35,0 40,0 45,0 50,0
Externe Kraft [N]
F
ixateurbelastung(Dehn
ung[m/m]
Bluetooth-Readout
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Bluetooth Readout
In-vivo use in Patients
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In vivo use in Patients
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Patient 2, 11.08.05, postop
0,0
100,0
200,0
300,0
400,0
500,0
600,0
0,000 50,000 100,000 150,000 200,000
Time [s]
Measured
data
Kraft [N] Fixateur (A/D Code [dez])
Physiotherapy
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Implantat-Biegebelastung bei KG-bungen
0%
100%
200%
300%
400%
500%
600%
Implantatbelastung unter 10kgaxial
max. Anspannung der OS-Muskulatur
Anheben des Beines inRckenlage
KG-bungen mitTorsionskomponente
Prozent
ys ot e apy
Outlook
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Routine Use
Telemedical Patient Supervision
Optimisation of postop. treatment regime
Future of External Fixation ?
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First external fixator(Wutzer, 1843)
Electronically Controlled (Electronically Controlled (IntelligentIntelligent))
External Fixator SystemsExternal Fixator Systems
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Measurement of fracture healingprogress
Detecting delayed healing orpseudarthrosis formation
Controlling patient activity bydisplay or voice
Actively controlling optimal load onthe fracture gap (Dynamisation)
Actively performing fracturereduction
y
Control
Unit
Force Sensors
Linear
Motors
Motor Driven FixatorMotor Driven Fixator
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Motor Driven FixatorMotor Driven Fixator
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R.L.08/2003
Motor Driven FixatorMotor Driven Fixator
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R.L.08/2003
33--Dimensional Load MeasurementsDimensional Load Measurements
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Fground
fixator
callus
bone
Fground
fixator
callus
bone
0
5
10
15
20
25
30
2 4 8 12
Mxy(Nmm/N)
0
5
10
15
20
25
30
2 4 8 12
time ( weeks )
Mxy(Nmm/N)
0
5
10
15
20
25
30
2 4 8 12 MZeit (Wochen)
Mxy(Nmm/N)
5 A2
6 A27 A2
8 B2
9 C3
0
5
10
15
20
25
30
2 4 8 12 MZeit (Wochen)
Mxy(Nmm/N)
1 A3
2 A3
3 A3
4 A3
Patient A: delayedfracture healing
Patient B: normalfracture healing
SummarySummary Universal and precise 3Universal and precise 3--dimensional bone movementsdimensional bone movements
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Universal and precise 3Universal and precise 3 dimensional bone movementsdimensional bone movements
Path of reduction / correction can be modified at any timePath of reduction / correction can be modified at any time
To be applied with different fixator systemsTo be applied with different fixator systems
Painless fracture reductionPainless fracture reduction
Motors and measurement additions possible (Motors and measurement additions possible (Intelligent FixatorIntelligent Fixator))
Very helpful addition to the treatment optionsVery helpful addition to the treatment options
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Thank You!Thank You!
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