Knee prosthesis system with standard and distal offset joint line

摘要

A modular knee prosthesis system includes a femoral component having a stem and a sleeve. The system is modular, and provides the surgeon with the option of distally offsetting the joint line by controlling the relative axial positions of the stem and the sleeve. Alternative options include providing sleeves with tapered bores of different diameters, providing a shim to be placed between the sleeve and the stem and providing the stems as adapters having different diameters.

主权项

1. A modular knee prosthesis system comprising:
a distal femoral component having a distal bone-facing surface, a pair of spaced, curved distal condylar surfaces and a stem having an outer surface tapering from a distal end in the proximal direction, the outer surface of the stem having a maximum outer diameter at the distal end and a smaller outer diameter at a second position proximal to the distal end; a first metaphyseal member having an outer surface that tapers in a proximal direction and an inner surface defining a tapered bore sized and shaped to be mountable on the stem of the distal femoral component and to create a frictional lock between the stem of the distal femoral component and the first metaphyseal member, the tapered bore having a maximum inner diameter at a distal end, the maximum inner diameter corresponding with the maximum outer diameter of the stem of the distal femoral component; the tapered bore of the first metaphyseal member having a central longitudinal axis that intersects a plane at the distal end of the stem of the distal femoral component when the first metaphyseal member is mounted on the stem of the distal femoral component, the distal end of the tapered bore and the plane being at a first distance; a second metaphyseal member having an outer surface that tapers in a proximal direction and an inner surface defining a tapered bore sized and shaped to be mountable on the stem of the distal femoral component and to create a frictional lock between the stem of the distal femoral component and the second metaphyseal member, the tapered bore having a maximum inner diameter at a distal end, the maximum inner diameter corresponding with the outer diameter of the stem of the distal femoral component at the second position so that the first metaphyseal member and the second metaphyseal member are mountable on the stem of the distal femoral component to create frictional locks at different positions in the proximal-distal direction on the stem of the distal femoral component; the tapered bore of the second metaphyseal member having a central longitudinal axis that intersects a plane at the distal end of the stem of the distal femoral component when the second metaphyseal member is mounted on the stem of the distal femoral component, the distal end of the tapered bore and the plane being at a second distance, the second distance being greater than the first distance; and a distal femoral augment having a thickness; wherein the difference between the first distance and the second distance defines a distal offset of the distal femoral component and the thickness of the distal femoral augment is substantially the same as the distal offset provided by the second metaphyseal member.