Femoral knee prosthesis system with augments and multiple lengths of sleeves sharing a common geometry

摘要

A modular knee prosthesis system includes a femoral component having a stem, a plurality of different sizes of sleeves mountable on the stem, and a plurality of different sizes of augments mountable on the femoral component. The system is modular, and provides the surgeon with the option of distally offsetting the joint line by selecting the size of sleeve that will provide the desired joint line. The different sizes of sleeves have different axial lengths but share a common geometry along a substantial part of their lengths so that the same bone cavity will accept multiple sizes of sleeves.

主权项

1. A modular knee prosthesis system, comprising: a distal femoral implant component having (i) a pair of spaced, curved distal condylar surfaces, (ii) a distal bone-facing surface, and (iii) a stem having an outer surface tapering from a distal end in a 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 distal femoral augment configured to be secured to the distal bone-facing surface of the distal femoral implant component, a proximal tibial implant component having an articulating surface to receive and articulate with the distal condylar surfaces of the distal femoral implant component and a stem, the stem having an outer surface tapering from a proximal end in the distal direction, the outer surface of the stem having a maximum outer diameter at the proximal end and a smaller outer diameter at a second position distal to the proximal end, a first metaphyseal member having an outer surface that tapers in the proximal direction and an inner surface defining a tapered bore sized and shaped to be mountable on the stem of one of the implant components and to create a frictional lock between the stem and the first metaphyseal member, the outer surface of the first metaphyseal member comprising a stepped portion having a plurality of steps, each step having a maximum medial-lateral dimension and a maximum anterior-posterior dimension, the stepped portion having an overall axial length L, and a second metaphyseal member having an outer surface that tapers in the proximal direction and an inner surface defining a tapered bore sized and shaped to be mountable on the stem of one of the implant components and to create a frictional lock between the stem and the second metaphyseal member, the outer surface of the second metaphyseal member comprising a stepped portion having a plurality of steps, each step having a maximum medial-lateral dimension and a maximum anterior-posterior dimension, the stepped portion having an overall axial length L+X, wherein (i) the maximum medial-lateral dimension of each step over the axial length L of the stepped portion of the second metaphyseal member is the same as the maximum medial-lateral dimension of each step over the axial length L of the stepped portion of the first metaphyseal member and the maximum anterior-posterior dimension of each step over the axial length L of the stepped portion of the second metaphyseal member is the same as the maximum anterior-posterior dimension of each step over the axial length L of the stepped portion of the first metaphyseal member so that the same prepared bone space will receive either the first metaphyseal member or the stepped portion of the second metaphyseal member having the axial length L, and (ii) the distal femoral augment has a thickness that is substantially equal to X, wherein the axial height of each step over the axial length L of the first metaphyseal member is equal to the axial height of each step over the axial length L of the second metaphyseal member,
wherein the distal femoral augment further includes (i) a tapered anterior surface configured to engage an anterior chamfer surface of the distal femoral implant component, (ii) a tapered posterior surface to engage a posterior chamfer surface of the distal femoral implant component when the distal femoral implant augment is secured to the distal bone-facing surface of the distal femoral augment component, and (iii) a posterior notch sized to receive a posterior femoral augment.