Revision hip prosthesis having an implantable distal stem component
View Patent ↗A modular femoral prosthesis for use during performance of a hip revision procedure includes a proximal body component, a distal stem component, and a locking bolt. Surgical instruments and methods for use in implanting such a modular femoral prosthesis are disclosed.
1. An implantable modular orthopaedic hip prosthesis system comprising:
an implantable proximal body component including a tapered bore and a bolt including a first set of male threads,
a stem insertion tool including (i) an impaction plate positioned at a proximal end, (ii) a second set of male threads formed at a distal end, (iii) and an alignment notch formed in the distal end, and
an implantable distal stem component configured to be separately secured to the implantable proximal body component and the stem insertion tool, the implantable distal stem component having (i) a tapered post formed in an outer surface thereof, the tapered post being configured to be received into the tapered bore of the implantable proximal body component, (ii) an upper set of female threads having a superior end that opens into a superior surface of the distal stem component, the upper set of female threads extending inferiorly into the distal stem component, (iii) a lower set of female threads having an superior end that opens into an inferior end of the upper set of female threads, the lower set of female threads extending inferiorly from the upper set of female threads, wherein the diameter of the upper set of female threads is larger than the diameter of the lower set of female threads, (iv) an alignment key extending superiorly from the superior surface of the distal stem component, the alignment key configured to be received into the alignment notch formed in the stem insertion tool, and (v) a slot defined in the upper set of female threads opposite from the alignment key and configured to receive a corresponding key, the slot including a curved back wall that defines a lobe-shape, the back wall extending inferiorly from the superior surface of the distal stem component,
wherein when the implantable distal stem component is secured to the stem insertion tool, the second set of male threads is engaged only with the upper set of female threads and spaced apart from the lower set of female threads, and
wherein when the implantable distal stem component is secured to the implantable proximal body component in place of the stem insertion tool, (i) the bolt is spaced apart from the upper set of female threads and the first set of male threads is engaged only with the lower set of female threads, and (ii) the tapered post of the implantable distal stem component is received in the tapered bore of the implantable proximal body component.
2. The implantable modular orthopaedic hip prosthesis system of claim 1 , wherein an inner-most diameter of the upper set of female threads of the implantable distal stem component is larger than an inner-most diameter of the lower set of female threads.
3. The implantable modular orthopaedic hip prosthesis system of claim 1 , wherein an outer-most edge of each of the female threads of the lower set of female threads is rounded.
4. The implantable modular orthopaedic hip prosthesis system of claim 1 , wherein the slot is formed in a sidewall of the distal stem component that defines the superior end of the upper set of female threads.
5. The implantable modular orthopaedic hip prosthesis system of claim 1 , wherein:
the distal stem component comprises a bowed distal stem component having an apex extending along a convex side thereof, and
the alignment key is positioned on a side of the bowed distal stem component corresponding with the apex.