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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.
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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 Director of the Departement for orthopedic and endoskopic joint surgery Ritter v. Schwarzstr. 8 5440-Hallein Guggenbichlerstr, 20 5020-Salzburg www.menapace.com
Modern concepts of knee implants Clemens MENAPACE M.D. Orthopedics and orthopedic surgery Director of the Departement for orthopedic and endoscopic joint surgery Ritter v. Schwarzstr. 8 5440-Hallein Guggenbichlerstr, 20 5020-Salzburg www.menapace.com
Modern concepts of knee implants Dr. Clemens Menapace Department for orthopedic and endoscopic joint surgery www.menapace.com
Modern concepts of knee implants Orthopedic surgery is getting more and more technically demanding
Modern concepts of knee implants Developement of state of the art kneeimplant was impaired by Biological complexity complicated biomechanics complicated anatomy of the knee Technical complexity Component- design problems Problems with materials
Modern concepts of knee implants Complex Biomechanics Biomechanically the knee contains 3 separate joints Medial lateral Femorotibial joint Femoropatellar joint The knee is a multi-ax system: center of ax-rotation changes during cycle of motion Flexion and Extension is a role- and glide - mechanism because of a negativ (decreasing) condyle-radius causing shear-forces During cycle of motion different combination of ligaments provide stability
Modern concepts of knee implants Complex Biomechanics 3 rotational axes of movement 1 axis with moving center of rotation rol & glide movement (translation-rotation) load-aera decreases in flexion (decreasing fc-radius) patellar biomechanic
Modern concepts of knee implants Complex Anatomy
Modern 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 implants Performance-requirements for an efficent kneeimplnat/-endoprothesis Stability Longevity Physiological range of motion without undue stress on components
Modern concepts of knee implants The ultimate goal is to imitate anatomy as close as possible
Modern concepts of knee implants Anatomically correct Decreasing /negativ radius of femurcondyles has to be imitated changing centers of rotation
Modern concepts of knee implants Restore perfect alignement Alignement deficiencies have to be corrected painstakingly to avoid peak-pressure locally valgus varus
Modern concepts of knee implants preop Planning of proper alignément postop
Modern concepts of knee implants Restore perfect ligament tension and balance
Modern concepts of knee implants Combination of low friction interface FemurTibia Ceeramics ceramics Ceramics Polyaethylen Metal Polyaethylen Metal Metal
Modern concepts of knee implants stabel fixation of components to bone cement Press fit screw fixation
Modern concepts of knee implants D e v e l o p m e n t
Modern concepts of knee implants Stoneage of knee-implants
Modern concepts of knee implants GSB-Hinge-Type 1970 semiconstraint Tour de France ?
Modern concepts of knee implants Fixed tbial bearing The Vienna Derby
Modern concepts of knee implants Mobile bearing Back into the future
Modern concepts of knee implants Congruency High contact stress Low contact stress
Modern concepts of knee implants Large contact area reduces contact stress
Modern concepts of knee implants Different qualities of force exacted on a fixed bearing implant
Modern concepts of knee implants Constraint means that shear and torsion forces could be transmitted to fixation interfaces and cause loosening
Modern concepts of knee implants Mobile bearing prevents sheering forces
Modern concepts of knee implants mobile patellar bearing
Modern concepts of knee implants cemented-noncemented mobile bearing system
Modern concepts of knee implants Revision-surgery
Modern concepts of knee implants Constraint systems in use for cases with severe bonedefect Tumor-surgery Revison-surgery
Modern concepts of knee implants Revision-surgery with semiconstraint knee -prosthesis after failure of duocondylar implant
Modern concepts of knee implants Semiconstraint implants for cases with sever bonedefect, instability, malalignement
Modern concepts of knee implants Unicondylar implants
Modern concepts of knee implants Unicondylar implants
Modern concepts of knee implants MGII NEXGEN
Modern concepts of knee implants Mobile bearing knee implant
Modern concepts of knee implants Duocondylar knee implnats Surgical principles of
Modern concepts of knee implants Defining the resection lines by using a weight bearing total limb X-ray Ahlbäcks desease