Modern Design of Total Knee Replacement

The developments in total knee designs since the 1970s are discussed. The stages include evolutionary steps such as the movement toward condylar replacements of moderate conformity, and the design of instrumentation systems for accurate and reproducible component seating and overall alignment, and the more “revolutionary” concepts such as an integrated graduated system of components, metal backing of the tibial component, modularity, ligament substituting designs, and meniscal bearing concepts. The major question today is which concepts will best satisfy the present requirements. These include optimum function, high durability, reproducibility, ease of operation, reasonable cost, and low inventory. The question can be answered only by an appraisal of the extensive clinical experience to date, biomechanical studies, and by newer methods of simulation testing for design and materials.