Dynamic Roentgen stereophotogrammetry has proven valuable in the evaluation of fixation for hip and knee arthroplasty, as early RSA evaluations have shown high predictive value for later aseptic component loosening. In contrast, Dynamic RSA makes it possible to accurately assess both micro movements in the fixation interface and kinematics of the prosthetic components in three dimensions, during active motions. Dynamic Roentgen stereophotogrammetry Dynamic Roentgen stereophotogrammetry (also referred to as dynamic RSA) is a modern and sophisticated x-ray recording method, used to measure real-time 3D motions of prostheses and bones during motion with high accuracy. It is mostly used in orthopedic research settings and
Multiple discovery pre-existing concepts and facts. This is what is meant when one says that a scientist or artist has been "influenced by" another—etymologically, that a concept of the latter's has "flowed into" the mind of the former. Not every new concept so formed will be viable: adapting social Darwinist Herbert Spencer's phrase, only the fittest concepts survive. Multiple independent discovery and invention, like discovery and invention generally, have been fostered by the evolution of means of communication: roads, vehicles, sailing vessels, writing, printing, institutions of education, reliable postal services, telegraphy, and mass media, including the internet. Gutenberg's invention of printing (which