Endosteal referencing in revision total knee arthroplasty

A method of orienting the femoral and tibial bone cuts relative to the endosteal cortex of the femur and tibia was used in 32 patients who underwent revision total knee arthroplasty. The mean orientation of the femoral component was 96.74 degrees +/- 1.03 degrees, mean orientation of the tibial baseplate was 90.71 degrees +/- 1.10 degrees, mean anatomic tibiofemoral alignment was 7.42 degrees +/- 1.69 degrees of valgus, and mean mechanical tibiofemoral alignment was 1.09 degrees +/- 1.83 degrees of valgus. Mean tibial bowing was 1.63 degrees +/- 1.57 degrees of valgus, and mean femoral bowing was 0.58 degrees +/- 1.53 degrees of varus. Valgus tibial bowing was correlated with valgus orientation of the tibial component (r = .86, P < .000001), and varus femoral bowing was correlated with orientation of the femoral component (r = .54, P = .0054). Referencing the implant position from the endosteal cortex of the intramedullary canals provides a reliable method of achieving satisfactory alignment in most revision total knee arthroplasties; however, bowing of the femur or tibia can affect alignment.