TKA Development in Japan: LFA

The amount of ultra-high molecular weight polyethylene (UHMWPE) wear with a ceramic femoral component is 20% of that with a cobalt-chrome (Co-Cr) alloy component [1]. Therefore, in 1992, the authors developed LFA (low friction, anatomical)-I total knee prosthesis that included an alumina ceramic femoral component. The clinical results of total knee arthroplasty (TKA) with the LFA-I prosthesis were equivalent to those previously reported for common metal prostheses [2]. However, there were some problems with the LFA-I prosthesis. The alumina ceramic component was relatively weak against impact loads, and it was impossible to manufacture an anatomically shaped component using alumina ceramic. To solve these problems, we developed the LFA-III total knee system (Fig. 6.1a–d) in 1999. In this system, the anatomically designed femoral component was made of zirconia ceramic, which has high toughness and low wear properties. In this system, cruciate-retention and posterior-stabilizing types were clinically available in 1999 and 2002, respectively.