Patent ID: 7582107

Claim:
A compression screw apparatus comprising: a) a primary screw having a leading end and an opposite trailing end, the primary screw having a lead portion configured for screwing into bone and the lead portion having an outer surface that is at least partially threaded and a trailing portion with a continuous outer surface that is at least partially threaded; b) a secondary screw having an outer surface that is at least partially threaded, the secondary screw defining a central opening with an inner surface that is at least partially threaded, the inner threaded surface being configured for mating engagement on the threaded trailing portion of the primary screw such that rotation of the secondary screw relative to the primary screw causes the translation of the secondary screw relative to the primary screw along the threaded trailing portion of the primary screw; c.) wherein the threads of the lead portion of the primary screw and the threads of the outer surface of the secondary screw are of at least substantially identical lead; and d.) wherein the threads of the trailing portion of the primary screw taper at least partially with a gradually decreasing diameter toward the trailing end of the primary screw.