Method and apparatus for attachment in a modular hip replacement or fracture fixation device
Methods and apparatus for orthopedic replacement of the hip and hip fracture fixation devices include structures and techniques for fixing or enhancing interconnection of implant components, such as by increasing the interconnection in an interference fit with one or more tapers, threads, and/or cooling of components prior to assembly. For example, a prosthetic femoral neck implant can include a thread and a Morse taper for lockable attachment to a prosthetic femoral head and/or intramedullary stem.
1. A method of attaching a prosthetic femoral neck to a prosthetic femoral head, comprising:
rotating a femoral neck component with respect to a femoral head component to engage a threaded interface between the femoral neck component and the femoral head component;
engaging a tapered cone surface on a distal portion of the femoral neck component with a tapered bore surface on a bore of the femoral head component;
lowering the temperature of at least a portion of the femoral neck component;
permitting the temperature of the portion of the femoral neck component to rise such that an interference fit between the femoral neck component and the femoral head component is increased
lowering the temperature of at least a portion of a third component;
interconnecting the portion of the third component with a portion of at least one of the femoral neck component and the femoral stem component in a second interference fit; and
permitting the temperature of the portion of the third component to rise such that the interference fit between the third component and one of the femoral neck component and the femoral stem component is increased.
2. The method of claim 1 , further comprising locking the threaded interface femoral head component.
3. The method of claim 1 , wherein the rotating to engage the threaded interface aligns the engagement of the femoral neck component and the femoral head component.
4. The method of claim 1 , wherein the rotating to engage the threaded interface controls a taper engagement force between the femoral neck component and the femoral head component.
5. The method of claim 1 , wherein the rotating step is configured to reduce any of the group consisting of fretting, corrosion, and material release from the femoral neck component and the femoral head component.
6. A method of attaching a prosthetic femoral neck to a prosthetic femoral stem, comprising:
rotating a femoral neck component with respect to a femoral stem component to engage a threaded interface between the femoral neck component and the femoral stem component;
engaging a tapered cone surface on a distal portion of the femoral neck component with a tapered bore surface on a bore of the femoral stem component;
lowering the temperature of at least a portion of the femoral neck component;
permitting the temperature of the portion of the femoral neck component to rise such that an interference fit between the femoral neck component and the femoral stem component is increased;
lowering the temperature of at least a portion of a third component;
interconnecting the portion of the third component with a portion of at least one of the femoral neck component and the femoral stem component in a second interference fit; and
permitting the temperature of the portion of the third component to rise such that the interference fit between the third component and the femoral neck component is increased.
7. The method of claim 6 , further comprising locking the threaded interface.
8. The method of claim 7 , wherein the rotating to engage the threaded interface controls a taper engagement force between the femoral neck component and the femoral stem component.
9. The method of claim 6 , wherein the rotating to engage the threaded interface aligns the engagement of the femoral neck component and the femoral stem component.
10. The method of claim 6 , wherein the rotating step is configured to reduce any of the group consisting of fretting, corrosion, and material release from the femoral neck component and the femoral stem component.