Variability in distal femoral anatomy in patients undergoing total knee arthroplasty: measurements on 13,546 computed tomography scans

Abstract

Proper mechanical and rotational alignment plays an important role in achieving the success of the total knee arthroplasty (TKA). The purpose of the present study was to retrospectively determine with computed tomography (CT) the distal femoral valgus angle (DFVA) and femoral rotation angle (FRA). Our cohort included 13,546 CT scans of patients undergoing TKA. The average DFVA was 5.7 +/- 2.3 degrees (range from 1 to - 16 degrees) with 13.8% of patients identified as outliers. The distal FRA angle average was 3.3 +/- 1.5 degrees (range from - 3 to 11 degrees) with 2.8% of patients identified as outliers. These data can be useful in making orthopedic surgeons aware of the variability of femoral anatomy. Using the same cutting angle may lead to malposition of the femoral component.