Patent ID: 8585743

Claim:
A screw and washer system, comprising: a) a screw having a non-threaded conical head and a shaft with bone engaging threads, said head of said screw provided with a distal end from which said shaft extends, and a proximal end opposite said shaft, said proximal end defining a convex top surface portion and a torque driver engagement portion; and b) a washer having a top, a bottom, a maximum vertical dimension extending between the top and bottom, a vertical center at a midpoint of said maximum vertical dimension, a maximum diameter provided above said vertical center, a smoothly curving exterior lower surface extending upward to said maximum diameter, an axial bore extending through said washer from said top to said bottom, said bore having an upper conical portion shaped to receive in mating contact the conical head and a lower cylindrical portion, and at least one interference element extending radially inward into said axial bore of the washer only above said upper smooth conical portion so that when said head of said screw is inserted into said axial bore of said washer with said conical head in mating contact against said conical portion of said bore, said at least one interference element extends above said conical portion and into contact about said convex top surface portion to retain said screw and washer as an assembly.