Experience with the Lord Prosthesis

Abstract

We have been using the cement-free Lord total hip system in our department for four years. Our confidence in this system is based upon the very high strength that is achieved when the components are implanted correctly. This strength derives not only from the interlock produced by bony ingrowth into the madreporic surface of the prosthesis but also from the manner in which the femoral component is seated within the medullary cavity and upon the greater trochanter. To achieve the strongest possible bond between the components and surrounding bone, Lord provided his components with a “madreporic” surface, i.e., a surface that is roughened by the deposition of numerous tiny beads, each having the shape of a 3/4 sphere. This enlarges the surface area by a factor of 3 while providing a framework for bone ingrowth. Animal studies have shown that this form of surface enlargement is superior to “negative” forms in which pores or recesses are used to increase surface area.