Bone anchors having two or more portions exhibiting different performance characteristics and method of forming the same

摘要

A bone anchor including a bone engaging element and an implant engaging element. The bone engaging element includes a first portion formed of a first material and a second portion formed of a second material and extending at least partially along a length of the first portion, and with the second portion of the bone engaging element positioned between the first portion and adjacent bone tissue when the bone engaging element is engaged with the bone to provide an interface with the adjacent bone tissue. In one embodiment, the first portion of the bone engaging element exhibits a first level of rigidity and the second portion exhibits a second level of rigidity less than the first level of rigidity. In another embodiment, the bone engaging element includes external threads, with the second portion of the bone engaging element defining at least a portion of the external threads.