Patent ID: 7524325

Claim:
An orthopedic implant assembly, comprising: a screw retention member, having a bore formed therethrough, the bore having top and bottom ends connected by a passageway having a first diameter at the top end and a second diameter at the bottom end, a tapered retention seat being formed along an intermediate portion of the passageway, the tapered retention seat comprising a shoulder formed at a bottom thereof and a wall that monotonically decreases in diameter over a height thereof; a frustoconical split ring, having inside and outside diameters that each decrease monotonically over a height thereof from a maximum diameter at a bottom, the split nature of the ring allowing expansion of the inside and outside diameters from a relaxed state; and a bone screw, comprising a shaft with a head at an end thereof, the head being generally spherical, with a bottom spherical portion, connected to the shaft, and a top spherical portion, the bottom and top spherical portions separated by a threaded section; wherein the split ring is removably seated in the retention seat and rotating engagement of the threaded section of the bone screw with the top inside diameter of the split ring lifts the split ring in the retention seat from a position below the bone screw head to a position above the bone screw head.