European Counterpoint to Chapter 24

Abstract

Drs. Otto and L’Hommedieu are to be commended for their account in Chapter 24 of the development of orthopedic implants. There are, however, a few points where I would disagree with their interpretation of history. They state that Charnley used a chromecobalt and high-density polyethylene combination and coined the term “low-friction arthroplasty” to describe the combination. In fact, Charnley used a stainless steel stem against a high-density polyethylene socket and the term “low-friction arthroplasty” is a contraction of the term “low-frictional torque arthroplasty.” The term does not describe the friction of the bearing surfaces but rather the low-turning moment on the outer surface of the socket consequent on the significant difference in diameter between the outer surface and the bearing surface arising as a result of the small femoral head (1). Charnley hoped that low frictional torque would reduce the force on the socket cement— bone interface and thereby reduce loosening rates. Stainless steel is still employed in the Charnley implant, the latest stems being made of a trademarked high nitrogen coldworked stainless steel called Ortron 90 (De Puy, Leeds, UK). Just as in the United States, British surgeons strive to improve the long-term results of joint replacement by employing cementless devices, alternate bearing surfaces (ceramic and metal on metal), and by revisiting the concept of surface replacement.