The classification system commonly used the Muller and Schatzker ones those relate grade to treatment ad outcome.
Recently it has been increasing the interest of theorthopaedic surgeon about those tools o devices to optimize the results of the replacement surgery. In fact in the last few years the incidence of operations executed in order to treat patients affected by osteoarthritis of the hip with THR is increased, and so the need ness of giving back more long-lived implants. For this reason new navigation systems, based CT have been developed, which, during surgey, can make the positioning hip and knee prosthesis easier. A pool of international workers (surgeon, engineers, etc.) has developed recently an articular navigation system based on surgery reliefs, using tools gauged and provided with visible markers detected by a computerized system which uses infrared cameras. For this reason new navigation systems, based CT have been developed, which, during surgey, can make the positioning hip and knee prosthesis easier. A pool of international workers (surgeon, engineers, etc.) has developed recently an articular navigation system based on surgery reliefs, using tools gauged and provided with visible markers detected by a computerized system which uses infrared cameras. In fact it is not based on CT images of thehip, but on direct data (kept during the operation) analysis, and for this reason the procedure should be more accurate.