Prosthetic knee design by simulation [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1999. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- PDF-FILE: 5 ; SIZE: 0.2 MBYTES pages
- Additional Creators:
- Lawrence Livermore National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
- Restrictions on Access:
- Free-to-read Unrestricted online access
- Although 150,000 total knee replacement surgeries are performed annually in North America, current designs of knee prostheses have mechanical problems that include a limited range of motion, abnormal gait patterns, patellofemoral joint dysfunction, implant loosening or subsidence, and excessive wear. These problems fall into three categories: failure to reproduce normal joint kinematics, which results in altered limb function; bone-implant interface failure; and material failure. Modern computer technology can be used to design, prototype, and test new total knee implants. The design team uses the full range of CAD-CAM to design and produce implant prototypes for mechanical and clinical testing. Closer approximation of natural knee kinematics and kinetics is essential for improved patient function and diminished implant loads. Current knee replacement designs are based on 19th Century theories that the knee moves about a variable axis of rotation. Recent research has shown, however, that knee motion occurs about two fixed, offset axes of rotation. These aces are not perpendicular to the long axes of the bones or to each other, and the axes do not intersect. Bearing surfaces of mechanisms that move about axes of rotation are surfaces of revolution of those axes which advanced CAD technology can produce. Solids with surfaces of revolution for the two axes of rotation for the knee have been made using an HP9000 workstation and Structural Ideas Master Series CAD software at ArthroMotion. The implant's CAD model should closely replicate movements of the normal knee. The knee model will have a range of flexion-extension (FE) from -5 to 120 degrees. Movements include varus, valgus, internal and external rotation, as well as flexion and extension. The patellofemoral joint is aligned perpendicular to the FE axis and replicates the natural joint more closely than those of existing prostheses. The bearing surfaces will be more congruent than current designs and should generate lower stresses in the materials.
- Published through SciTech Connect., 07/30/1999., "ucrl-id-138971", and Hollerbach, K; Hollister, A.
- Funding Information:
View MARC record | catkey: 13811276