How to increase hip ROM by 20° for impingement-free motion that avoids dislocations.

A dry hip will move 223 degrees. We can, if we make it side-specific, we don't get any extra movement, we just alter the arc of movement. So we can balance those two arcs. And down the bottom there just shows you a standard hip, a Koraya, an Exeter, how it impinges. The chamfers on the neck are actually quite useless, but if you see this elliptical neck that's modified and rifled, etc., we can actually reduce the impingement. And even if it does occur, it's less, less aggressive. So we can reduce posterior prosthetic impingement as well. So we get an extra 20 degrees range of movement. So size-specific stems increase both flexion extension before impingement occurs, will reduce multiple risks, and the extra 20 degrees range of motion enlarges the Levenix safe zone.