Modern concepts of knee Modern concepts of knee implants implants Dr. Clemens Dr. Clemens Menapace Menapace FA für Orthopädie und FA für Orthopädie und orthop. Chirurgie orthop. Chirurgie Ritter v. Schwarzstr. 8, Ritter v. Schwarzstr. 8, 5400 - Hallein 5400 - Hallein www.menapace.co www.menapace.co m m
Modern concepts of knee implants. Dr. Clemens Menapace FA für Orthopädie und orthop. Chirurgie Ritter v. Schwarzstr. 8, 5400 - Hallein. www.menapace.com. Modern concepts of knee implants. Clemens MENAPACE. M.D. Orthopedy and orthopedic surgery. - PowerPoint PPT Presentation
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Modern concepts of knee implantsModern concepts of knee implantsModern concepts of knee implantsModern concepts of knee implants
Dr. Clemens Dr. Clemens
MenapaceMenapace
FA für Orthopädie und orthop. ChirurgieFA für Orthopädie und orthop. Chirurgie
Ritter v. Schwarzstr. 8, 5400 - Hallein Ritter v. Schwarzstr. 8, 5400 - Hallein
www.menapace.comwww.menapace.com
Director of Director of the Departement for the Departement for
orthopedic and endoskopic orthopedic and endoskopic joint surgeryjoint surgery
Ritter v. Schwarzstr. 8 Ritter v. Schwarzstr. 8 5440-Hallein5440-Hallein
The knee is a multi-ax system: center of ax-rotation changes during cycle The knee is a multi-ax system: center of ax-rotation changes during cycle of motionof motion
Flexion and Extension is a role- and glide - mechanism because of a Flexion and Extension is a role- and glide - mechanism because of a negativ (decreasing) condyle-radius causing shear-forcesnegativ (decreasing) condyle-radius causing shear-forces
During cycle of motion different combination of ligaments provide stabilityDuring cycle of motion different combination of ligaments provide stability
Complex BiomechanicsComplex Biomechanics
Modern concepts of knee implantsModern concepts of knee implants
Complex Complex
BiomechanicsBiomechanics3 rotational axes of movement 3 rotational axes of movement
1 axis with moving center of rotation1 axis with moving center of rotation
rol & glide movement (translation-rol & glide movement (translation-rotation)rotation)
load-aera decreases in flexionload-aera decreases in flexion
(decreasing fc-radius)(decreasing fc-radius)
patellar biomechanicpatellar biomechanic
Modern concepts of knee implantsModern concepts of knee implants
Complex AnatomyComplex Anatomy
Modern concepts of knee implantsModern concepts of knee implants
In conclusion the Flexion / Extension movement of the knee is not a fixed hinge type system but rather a dynamic role- and glide- mechanism with an endrotation in full extension. Flexion and
extension is performed along several axes with dynamic centers of rotation secured statically by changing combinations of
ligaments and dynamically by groups/combinations of muscels.
Modern concepts of knee implantsModern concepts of knee implants
Performance-requirements for an Performance-requirements for an efficent kneeimplnat/-endoprothesisefficent kneeimplnat/-endoprothesis
Physiological range of motion without undue stress on components
StabilityStability
LongevityLongevity
Modern concepts of knee implantsModern concepts of knee implants
The ultimate goal is to imitate The ultimate goal is to imitate anatomy as anatomy as close as possibleclose as possible
Modern concepts of knee implantsModern concepts of knee implants
Anatomically correctAnatomically correctDecreasing /negativ radius of femurcondyles has to be imitated Decreasing /negativ radius of femurcondyles has to be imitated
changing changing centers of centers of rotation rotation
Modern concepts of knee implantsModern concepts of knee implants
Modern concepts of knee implantsModern concepts of knee implants
Fixed tbial bearing
The Vienna Derby
Modern concepts of knee implantsModern concepts of knee implants
Mobile bearing Back into the futureBack into the future
Modern concepts of knee implantsModern concepts of knee implants
CongruencyCongruency
High contact High contact stressstress
Low contact Low contact stressstress
Modern concepts of knee implantsModern concepts of knee implants
Large contact area reduces Large contact area reduces contact stresscontact stress
Modern concepts of knee implantsModern concepts of knee implants
Different qualities of force exacted on a fixed bearing implantDifferent qualities of force exacted on a fixed bearing implant
Modern concepts of knee implantsModern concepts of knee implants
Constraint means that shear and torsion Constraint means that shear and torsion forces could be transmitted to fixation forces could be transmitted to fixation
interfaces and cause looseninginterfaces and cause loosening
Modern concepts of knee implantsModern concepts of knee implants
Mobile bearing prevents sheering forcesMobile bearing prevents sheering forces
Modern concepts of knee implantsModern concepts of knee implants
Modern concepts of knee implantsModern concepts of knee implants
Modern concepts of knee implantsModern concepts of knee implants
Modern concepts of knee implantsModern concepts of knee implants
mobile patellar bearingmobile patellar bearing
Modern concepts of knee implantsModern concepts of knee implants
cemented-noncemented mobile bearing systemcemented-noncemented mobile bearing system
Modern concepts of knee implantsModern concepts of knee implants
Revision-surgeryRevision-surgery
Modern concepts of knee implantsModern concepts of knee implants
Constraint systems in use for cases with severe bonedefectConstraint systems in use for cases with severe bonedefect
Tumor-surgery
Revison-surgery
Modern concepts of knee implantsModern concepts of knee implants
Revision-surgery with semiconstraint knee -Revision-surgery with semiconstraint knee -prosthesis after failure of duocondylar implantprosthesis after failure of duocondylar implant
Modern concepts of knee implantsModern concepts of knee implants
Semiconstraint implants for cases with sever Semiconstraint implants for cases with sever bonedefect, instability, malalignementbonedefect, instability, malalignement
Modern concepts of knee implantsModern concepts of knee implants
Unicondylar implantsUnicondylar implants
Modern concepts of knee implantsModern concepts of knee implants
Unicondylar implantsUnicondylar implants
Modern concepts of knee implantsModern concepts of knee implants
Modern concepts of knee implantsModern concepts of knee implants
MGII MGII NEXGENNEXGEN
Modern concepts of knee implantsModern concepts of knee implants
Mobile bearing knee implantMobile bearing knee implant
Modern concepts of knee implantsModern concepts of knee implants