In addition to pioneering a hemi-arthroplasty (described in the first part of this series of articles), Themistocles Gluck is credited with the first hinged total knee prosthesis in 1891. It was made of ivory and was held in place with a cement made from colophony, pumice and gypsum. It was said that these implants resorbed quickly! It was not until the 1950s with the advent of non-reactive metals that hinges became the standard type of arthroplasty. The need for a hinge was 'self-evident'; the arthritic knee was unstable and therefore it was essential to provide stability via the implant. The failure to understand that the primary cause of instability in the rheumatoid knee was cartilage and bone loss, not the disruption of the collateral ligaments, was to delay the introduction of reliable knee replacement for two decades.
Borje Walldius from Sweden first inserted an acrylic resin prototype in severe rheumatoid patients in Octo-ber1951. Some cases were successful and two wheelchair bound patients regained an ability to walk. 1 One of these joints functioned well for 18 years. Subsequent prostheses were made from metal, due to breakages of the acrylic and better perceived wear properties of metal. 2--4 Initially stainless steel with a Teflon roller bearing was used, but this bearing was later replaced by a cobaltchrome alloy coupling bolt secured by a locking nut (Fig. ). Note that the prosthesis did not have a valgus angle to the femoral stem i.e. it was a universal right and left prosthesis. In 1958 the Walldius knee was modified to incorporate a patellar flange and longer stems for the