TY - GEN

T1 - Belt Machining and Testing of Ceramic Knee Implants

AU - Denkena, B.

AU - De Leon, L.

AU - Turger, Anke

AU - Richter, B.

AU - Hurschler, C.

PY - 2009/12/1

Y1 - 2009/12/1

N2 - Currently about five million people are diseased by arthrosis. This painful inflammation is often attended by an artificial joint replacement. Due to immune reactions resulting from the agglomeration of the polyethylene wear implant loosening appears. In the field of hip endoprostheses the functionality of ceramic hip implants is well known since many years. To minimize the necessary revision surgeries bioceramics will be also used for knee implants. However, the use of bioceramic hard-hard-pairings for total knee arthroplasty results in high demands on the geometrical accuracy as well as the surface topography of such complex implants. Since ceramics cannot cope with non-uniform loads, a new adapted design for ceramic knee implants is required. Hence, the biomechanical requirements have been investigated. In a roll-gliding wear simulator specimens of simplified geometries have been tested under movements and stresses similar to the knee joint. Due to the fact that the complex implants will be machined in one clamping, the high geometrical requirements can be achievable. After 5-axis-grinding with torical grinding pins the polishing process with flexible tools takes place in the same machine. Two concepts for flexible polishing tools are traced. Here, a new belt apparatus for flexible polishing is presented in addition to flexible rubber tools with bonded diamond grains.

AB - Currently about five million people are diseased by arthrosis. This painful inflammation is often attended by an artificial joint replacement. Due to immune reactions resulting from the agglomeration of the polyethylene wear implant loosening appears. In the field of hip endoprostheses the functionality of ceramic hip implants is well known since many years. To minimize the necessary revision surgeries bioceramics will be also used for knee implants. However, the use of bioceramic hard-hard-pairings for total knee arthroplasty results in high demands on the geometrical accuracy as well as the surface topography of such complex implants. Since ceramics cannot cope with non-uniform loads, a new adapted design for ceramic knee implants is required. Hence, the biomechanical requirements have been investigated. In a roll-gliding wear simulator specimens of simplified geometries have been tested under movements and stresses similar to the knee joint. Due to the fact that the complex implants will be machined in one clamping, the high geometrical requirements can be achievable. After 5-axis-grinding with torical grinding pins the polishing process with flexible tools takes place in the same machine. Two concepts for flexible polishing tools are traced. Here, a new belt apparatus for flexible polishing is presented in addition to flexible rubber tools with bonded diamond grains.

KW - Belt polishing

KW - Ceramic implants

KW - Gravimetrical wear detection

KW - Machining

KW - Roll-gliding-test-station

UR - http://www.scopus.com/inward/record.url?scp=77950155072&partnerID=8YFLogxK

U2 - 10.1007/978-3-642-03882-2-255

DO - 10.1007/978-3-642-03882-2-255

M3 - Conference contribution

AN - SCOPUS:77950155072

SN - 9783642038815

T3 - IFMBE Proceedings

SP - 958

EP - 961

BT - World Congress on Medical Physics and Biomedical Engineering

T2 - World Congress on Medical Physics and Biomedical Engineering: Image Processing, Biosignal Processing, Modelling and Simulation, Biomechanics

Y2 - 7 September 2009 through 12 September 2009

ER -