Implant and anchor assembly

1. An implant assembly comprising:

an implant including:

an implant body having a load bearing surface with a contour corresponding to a patient's articular surface, a bone facing surface, a fixation ring extending outward generally below said bone facing surface, and at least one recess extending at least partially around an outer perimeter of the fixation ring, wherein said load bearing surface comprises a plastic composition or a metal composition; and

an implant fixation member comprising at least one fastener segment configured to snap into said at least one recess to couple said implant fixation member to said implant body, said implant fixation member further including a first fixation element comprising either a plastic composition or a metal composition;

an anchor configured to be secured to bone beneath said patient's articular surface, said anchor including a second fixation element; and

wherein said first fixation element is configured to be secured to said second fixation element; and

wherein when said first fixation element comprises said plastic composition, said second fixation element comprises a plastic composition and said load bearing surface comprise a metal composition; or

wherein when said first fixation element comprises said metal composition, said second fixation element comprises a metal composition and said load bearing surface comprise a plastic composition.

2. The implant assembly of claim 1 , wherein:

said load bearing surface of implant comprises said plastic composition; and

said first fixation element comprises said metal composition and said second fixation element comprises said metal composition.

3. The implant assembly of claim 1 , wherein:

said load bearing surface of said implant comprises said metal composition; and

said first fixation element comprises said plastic composition and said second fixation element comprises said plastic composition.

4. The implant assembly of claim 1 , wherein:

said first fixation element and said second fixation element are configured to mechanically connect with each other to form a mechanical connection therebetween.

5. The implant assembly of claim 4 , wherein:

said first fixation element and said second fixation element are further configured to frictionally engage with each other to form a frictional connection therebetween.

6. The implant assembly of claim 5 , wherein:

said first fixation element includes a tapered portion and said second fixation element includes a tapered portion; and

said tapered portions are configured to frictionally engage with each other to form said friction connection therebetween.

7. The implant assembly of claim 5 , wherein:

said first fixation element comprises a tapered recess; and

said second fixation element comprises a tapered protrusion.

8. The implant assembly of claim 5 , wherein:

said first fixation element comprises a tapered protrusion; and

said second fixation element comprises a tapered recess.

9. The implant assembly of claim 5 , wherein:

one of said first fixation element or said second fixation element comprises a protrusion having a protrusion sidewall; and

said protrusion sidewall includes at least one protrusion sidewall fixation feature.

10. The implant assembly of claim 9 , wherein:

said at least one protrusion sidewall fixation feature comprises at least one barb.

11. The implant assembly of claim 10 , wherein:

said at least one barb comprises at least one barb ring which extends around a circumference of said protrusion.

12. The implant assembly of claim 11 , wherein:

said at least one barb ring extends continuously around said circumference of said protrusion.

13. The implant assembly of claim 11 , wherein:

said at least one barb ring comprises a plurality of barb ring segments which extend around said circumference of said protrusion.

14. The implant assembly of claim 11 , wherein:

said at least one barb comprises at least two barb rings which extends around a circumference of said protrusion.

15. The implant assembly of claim 14 , wherein:

each of said at least two barb rings comprises a plurality of barb ring segments which extend around said circumference of said protrusion; and

said plurality of barb ring segments of each of said at least two barb rings are laterally offset relative to one another around said circumference of said protrusion.

16. The implant assembly of claim 9 , wherein:

said at least one protrusion sidewall fixation feature comprises at least one rib.

17. The implant assembly of claim 16 , wherein:

said at least one rib comprises a plurality of ribs.

18. The implant assembly of claim 17 , wherein:

said plurality of ribs extend substantially longitudinally along a longitudinal length of said protrusion.

19. The implant assembly of claim 17 , wherein:

said plurality of ribs are substantially equally spaced around a circumference of said protrusion.

20. The implant assembly of claim 17 , wherein:

said plurality of ribs are substantially parallel to each other.

21. The implant assembly of claim 4 , wherein:

said first fixation element and said second fixation element are further configured to mechanically interlock with each other to form a positive mechanical engagement therebetween.

22. The implant assembly of claim 21 , wherein:

said first fixation element comprises a tapered recess and wherein said second fixation element comprises a tapered protrusion.

23. The implant assembly of claim 21 , wherein:

said first fixation element comprises a tapered protrusion and wherein said second fixation element comprises a tapered recess.

24. The implant assembly of claim 21 , wherein:

one of said first fixation element or said second fixation element comprises a protrusion having a protrusion sidewall; and

said protrusion sidewall includes at least one protrusion sidewall fixation feature; and

said other of said first fixation element or said second fixation element comprises a recess having a recess sidewall; and

said recess sidewall includes at least one recess sidewall retention feature.

25. The implant assembly of claim 24 , wherein:

said at least one protrusion sidewall fixation feature is configured to mate with said at least one recess sidewall fixation feature to form said mechanical interlock.

26. The implant assembly of claim 24 , wherein:

said at least one protrusion sidewall fixation feature comprises at least one barb;

said at least one recess sidewall fixation feature comprises at least one ridge; and

said at least one barb is configured to cooperate with said at least one ridge to form said mechanical interlock.

27. The implant assembly of claim 24 , wherein:

said at least one protrusion sidewall fixation feature comprises at least one projection; and

said at least one recess sidewall fixation feature comprises at least one indentation; and

said at least one projection is configured to mate with said at least one indentation to form said mechanical interlock.

28. The implant assembly of claim 1 , wherein:

at least a portion of said anchor includes a threaded portion configured to engage said bone.

29. The implant assembly of claim 1 , wherein:

said implant is a synovial joint implant.

30. The implant assembly of claim 1 , wherein:

said implant is a ball and socket joint implant.

31. The implant assembly of claim 1 , wherein:

said implant is a shoulder joint implant.

32. The implant assembly of claim 1 , wherein said first fixation element and said second fixation element form a Morse tapered connection.

33. The implant assembly of claim 1 , wherein said at least one recess extends continuously around the perimeter of the fixation ring.