Arthroplasty systems and methods
Systems for joint arthroplasty include prostheses which are secured to bone with sliding anchors. Examples include unicondylar and bicondylar knee prostheses for hemi-arthroplasty and total arthroplasty. Instruments guide the anchors into proper engagement with the prosthetic components. Methods of using the prostheses and instruments are disclosed.
1. A joint arthroplasty system, comprising:
a prosthetic articular surface which replaces at least a portion of a natural articular surface of a bone;
a prosthetic component comprising a bone-contacting surface configured to compliment a resected or flattened bone surface, the bone-contacting surface comprising at least one undercut channel extending across at least a portion of the bone-contacting surface and through a perimeter edge of the bone-contacting surface; and
an anchor comprising a rail, a blade, and a support, the rail comprising at least one lateral protrusion, the blade offset from the rail, the support connecting the rail and the blade;
wherein the rail is insertable into the channel to connect the anchor to the prosthetic component;
wherein, when the rail is inserted into the channel, the support protrudes through the bone-contacting surface, and the blade is carried at a distance from the bone-contacting surface, characterized in that the lateral protrusion is adapted such that, when the rail is inserted into the channel, the lateral protrusion plastically deforms to create an interference fit in the channel.
2. The system of claim 1 , wherein the prosthetic component is selected from the group consisting of a knee tibial component, a knee femoral component, and a knee patellar component.
3. The system of claim 1 , wherein the prosthetic articular surface is opposite the bone-contacting surface.
4. The system of claim 1 , wherein the channel comprises at least one shoulder formed in an edge of the channel, wherein the shoulder deforms the lateral protrusion when the rail is inserted into the channel.
5. The system of claim 1 , wherein the system is a knee arthroplasty system and wherein the prosthetic articular surface replaces at least a portion of a natural articular surface of a knee joint.
6. The system of claim 5 , wherein the articular and bone-contacting surfaces are connected to a prosthesis selected from the group consisting of a knee tibial prosthesis, a knee femoral prosthesis, and a knee patellar prosthesis.
7. The system of claim 6 , wherein the prosthesis is selected from the group consisting of a unicondylar prosthesis and a bicondylar prosthesis.
8. The system of claim 1 , wherein a transverse cross section of the channel and a transverse cross section of the rail are complementary negative and positive dovetail shapes, respectively.
9. The system of claim 1 , wherein the blade is inclined at an acute angle relative to the bone-contacting surface when the rail is in the channel.
10. The system of claim 1 , wherein a leading end of the anchor includes oblique sharpened edges.
11. The system of claim 5 , wherein, when the rail is inserted into the channel, the rail seizes in the channel.
12. A method of assembling a joint arthroplasty prosthesis for replacing at least a portion of a natural articular surface of a synovial joint, comprising:
providing a prosthesis comprising a bone-contacting surface configured to compliment a resected or flattened bone surface and an articular surface, the bone-contacting surface comprising at least one undercut channel extending across at least a portion of the bone-contacting surface and through a perimeter edge of the bone-contacting surface, the articular surface replicating at least a portion of a natural articular surface of a synovial joint;
providing an anchor comprising a rail, a blade, and a support, the rail comprising at least one laterally protruding tab, the blade offset from the rail, the support connecting the rail and the blade;
sliding the rail into the channel, wherein the tab plastically deforms as the rail slides into the channel to create an interference fit in the channel; and
sliding a portion of the support into the channel, the support protruding through the bone-contacting surface, wherein a portion of the bone-contacting surface is spaced between the blade and the rail when the rail and the support are in the channel.
13. The method of claim 12 , wherein sliding the rail into the channel is performed before sliding the portion of the support into the channel.
14. The method of claim 12 , wherein sliding the rail into the channel further comprises sliding the tab past a shoulder formed in an edge of the channel, wherein the shoulder deforms the tab.
15. The method of claim 12 , wherein the blade is inclined at an acute angle relative to the bone-contacting surface when the rail is in the channel, wherein the acute angle opens toward a leading end of the anchor.
16. The method of claim 12 , further comprising:
providing a guide tool comprising an attachment portion and a guidance portion, the attachment portion releasably attachable to a portion of the prosthesis, the guidance portion including at least one track;
attaching the attachment portion to the prosthesis, wherein the track coaxially aligns with the channel when the attachment portion is attached to the prosthesis;
inserting the rail into the track; and
sliding the anchor toward the prosthesis.
17. The method of claim 16 , wherein attaching the attachment portion to the prosthesis comprises attaching a clip to the attachment portion and snapping the clip to the prosthesis.