Modular implant system with fully porous coated sleeve

Abstract

A modular knee implant system allows a surgeon to select between several different styles of distal femoral implant components and several different styles of stem extensions while also allowing for use of a metaphyseal component. The metaphyseal component can be a universal one that is usable with all of the styles of distal femoral implant components through use of an adapter. A second adapter allows for use of stem extensions with different types of connectors with the metaphyseal component. A separate metaphyseal component could also be provided with a distal Morse taper post to mate with a distal femoral component having a proximal Morse taper bore. The metaphyseal component may have an outer surface that is configured to maximize contact area with the patient's bone, and may have a surface finish over a substantial part of its overall length that is conducive to bone ingrowth.

1 . A modular orthopaedic knee implant system comprising:
 a distal femoral component;   a tapered metaphyseal component having a distal end and a proximal end with a proximal opening at the proximal end and an interior surface defining a proximal tapered bore extending from the proximal opening toward the distal end of the tapered metaphyseal component, the tapered metaphyseal component being mountable to the distal femoral component, the tapered metaphyseal component having an outer surface including a plurality of steps and being widest at its distal end;   a first femoral stem extension having a distal end and a proximal end, the distal end comprising a tapered post shaped and sized to be received in and frictionally mate with the proximal tapered bore the tapered metaphyseal component;   a second femoral stem extension having a distal end and a proximal end, the distal end of the second femoral stem extension comprising a threaded post; and   a stem adapter for connecting the second femoral stem extension to the tapered metaphyseal component, the stem adapter having a central longitudinal axis, a distal end including a tapered post and a proximal end with a proximal opening at the proximal end and an interior surface defining a threaded bore extending from the proximal opening toward the distal end of the stem adapter, the threaded bore being shaped and sized to engage the threaded post of the second femoral stem extension;   wherein the tapered post of the stem adapter has a longitudinal axis and the threaded bore of the stem adaper has a longitudinal axis co-linear with the longitudinal axis of the tapered post of the stem adapter and the longitudinal axes of the tapered post and threaded bore are co-linear with the central longitudinal axis of the stem adapter.   
   
   
       2 . The modular orthopaedic knee implant system of  claim 1  wherein the tapered metaphyseal component has a distal opening at the distal end and an interior surface defining a distal bore extending from the distal opening toward the proximal end of the tapered metaphyseal component. 
   
   
       3 . The modular orthopaedic knee implant system of  claim 2  further comprising a second adapter having a tapered proximal outer surface shaped and sized to be received within and frictionally lock with the distal bore of the tapered metaphyseal component. 
   
   
       4 . The modular orthopaedic knee implant system of  claim 3  further comprising a bolt for connecting the second adapter to the distal femoral component. 
   
   
       5 . The modular orthopaedic knee implant system of  claim 2  wherein the distal femoral implant component includes a post shaped and sized to be received within and frictionally lock with the distal bore of the tapered metaphyseal component. 
   
   
       6 . The modular orthopaedic knee implant system of  claim 2  wherein the distal femoral component has a pair of spaced, curved distal articulating surfaces, a proximal end opposite the articulating surfaces, an interior surface defining a tapered bore at the proximal end, the tapered bore being widest at the proximal end and extending distally from the proximal end, and an exterior surface spaced from the distal articulating surfaces, at least a portion of the exterior surface surrounding the tapered bore, the portion of the exterior surface surrounding the tapered bore being asymmetrical in at least one cross-section, the maximum dimension of the distal femoral component in the proximal-distal direction being the distance from the distal articulating surfaces to the proximal end. 
   
   
       7 . The modular orthopaedic knee implant system of  claim 6  further comprising a second adapter having a central longitudinal axis and comprising a first tapered post sized and shaped to be receivable within the tapered bore of the distal femoral component and to create a frictional lock between the distal femoral component and the second adapter, the second adapter further comprising a second tapered post sized and shaped to be receivable within the distal tapered bore of the tapered metaphyseal component, wherein the first and second tapered posts of the second adapter are aligned along the central longitudinal axis of the second adapter and are widest at a location between the ends of the second adapter.