A new compression design that increases proximal locking screw bending resistance in femur compression nails

The aim is to present our new method of compression, a compression tube instead of conventional compression screw and to investigate the difference of proximal locking screw bending resistance between compression screw application (6 mm wide contact) and compression tube (two contact points with 13 mm gap) application. We formed six groups each consisting of 10 proximal locking screws. On metal cylinder representing lesser trochanter level, we performed 3-point bending tests with compression screw and with compression tube. We determined the yield points of the screws in 3-point bending tests using an axial compression testing machine. We determined the yield point of 5 mm screws as 1963±53 N (mean±SD) with compression screw, and as 2929±140 N with compression tubes. We found 51% more locking screw bending resistance with compression tube than with compression screw (p=0,000). Therefore compression tubes instead of compression screw must be preferred at femur compression nails.