Patent ID: 7833226

Claim:
A bone fixation device, comprising: one or more plates, each comprising: a bone-contacting surface; an upper surface opposite the bone-contacting surface; and one or more fastener-receiving apertures extending through the plate from the upper surface to the bone-contacting surface, wherein at least one fastener-receiving aperture comprises: a major opening proximate the upper surface, wherein the major opening comprises a frustoconical inner surface; a minor opening between the upper surface and the bone-contacting surface; and a cylindrical channel extending from the minor opening to the bone-contacting surface; one or more fixed screws having a head that has an upper surface, an arcuate lower surface and a threaded shaft extending from the arcuate lower surface, wherein the arcuate lower surface of the fixed screw head faces and is in contact with the frustoconical inner surface of the fastener-receiving aperture during fixation of a bone with the device and the arcuate lower surface of the fixed screw interfaces with the frustoconical inner surface of the fastener-receiving aperture at an interface, the interface providing a ring of contact between the arcuate lower surface of the screw and the frustoconical inner surface of the fastener-receiving aperture, wherein the shaft includes an upper shaft having a diameter that matches a diameter of the cylindrical channel, wherein the upper shaft is positioned within the channel during fixation of a bone with the device, fixing the position of the screw relative to the plate; and one or more variable screws including a head having an upper surface, an arcuate lower surface and a shaft extending from the arcuate lower surface, the head having a diameter that is greater than a diameter of the minor opening, wherein the arcuate lower surface of the screw head faces and is in contact with the frustoconical inner surface of the fastener-receiving aperture during fixation of a bone with the device, the shaft including an upper shaft having a diameter that is less than the diameter of the cylindrical channel such that a longitudinal axis of the variable screw may be positioned at an angle relative to a longitudinal axis of the channel during fixation of a bone with the device.