<qa>  What is the name of the prosthesis used to preserve the bone in the upper feBased on the foregoing disadvantages of the femoral components, which are commonly used, has for years been experimenting with the introduction of shorter implants, which are either anchored in the femoral neck or femoral neck combined with the very top end of the femur bone metaphysis. By using such a prosthesis, it is proven to preserve the bone in the upper femur forward and avoids the disadvantage in terms of the above described femoral pain. There is also described problems by using these short prostheses, especially in the form of solution, and pain secondary to anchor bolts in the upper femur forward. 