Surgical joint implant and a bone-mountable rig

Abstract

A surgical joint implant has a cap in the form of at least two intersecting circles of the same diameter having an articular outer surface and an inner surface for bone adhesion. At the center of each circle a peg, for bone insertion into a hole of a nominal diameter, extends. One peg is slightly larger than said nominal diameter, to achieve an interference fit and the other peg is slightly thinner, to achieve a slide fit. A tubular drill rig open at both ends and having an interior circumference corresponding to the outer shape of the implant, can be mounted over the bone surface to be repaired. It accommodates a double drill for drilling, at the same time, a shallow hole of the diameter of the intersecting circle and a deeper narrow hole at the center of the circle of said nominal diameter.

1 . Surgical The surgical joint implant having a cap with an articular outer surface and an inner surface adapted for bone adhesion, said cap having at least first and second pegs extending from said inner surface for anchoring said implant in a bone, characterized in that said at least first and second pegs have the same nominal diameter and that the diameter of said first peg deviates positively from said nominal diameter to provide an interference fit in relation to said nominal diameter and in that said second peg deviates negatively from said same nominal diameter to provide a clearance fit in relation to said same nominal diameter. 
     
     
         2 . The surgical joint implant according to  claim 1 , wherein said first peg deviates from said nominal diameter to provide a force fit in relation to said nominal diameter. 
     
     
         3 . The surgical joint implant according to  claim 1 , wherein said second peg deviates from said nominal diameter to provide a slide fit in relation to said nominal diameter. 
     
     
         4 . The surgical joint implant according to  claim 1 , wherein a third peg which deviates from said nominal diameter to provide a slide fit in relation to said nominal diameter. 
     
     
         5 . The surgical joint implant according to  claim 1 , wherein said cap has the form of two intersecting circles of the same diameter, said first and second pegs being disposed at the centers of the respective circles. 
     
     
         6 . The surgical joint implant according to  claim 4 , wherein the cap has the form of three intersecting circles of the same diameter, said first, second and third pegs being disposed at the centers of the respective circles. 
     
     
         7 . The surgical joint implant according to  claim 1 , wherein one of the pegs is significantly longer than the others. 
     
     
         8 . The surgical joint implant according to  claim 1 , wherein said articular outer surface is individually custom-formed. 
     
     
         9 . The surgical joint implant according to  claim 1 , wherein said inner surface adapted for bone adhesion and the surfaces of said pegs have an outer layer of a substance that promotes bone growth. 
     
     
         10 . A rig for correct drilling and insertion of a surgical joint implant as claimed in  claim 1 , having a hollow tubular shell open at both ends, wherein the interior of said shell defines at least first and second intersecting right circular cylinders of equal diameter. 
     
     
         11 . The rig according to  claim 10 , wherein the interior of said shell defines first, second and third intersecting right circular cylinders of equal diameter. 
     
     
         12 . The rig according to  claim 10 , wherein an arcuate wall is selectively insertable into said shell interior to complete the full circumference, as desired, one of said right circular cylinders. 
     
     
         13 . The rig according to  claim 10 , wherein the bone-engaging end of said hollow tubular shell is shaped to conform to the shape of the joint surface in which the implant is to be inserted. 
     
     
         14 . The rig according to  claim 10 , wherein said rig is provided with multiple holes for pins anchoring the rig securely in place on the surface to be repaired.