Miyasaka T, Saito M, Kurosaka D, et al. - This study was intended to evaluate the effect of posterior femoral condylar cartilage and posterior intercondylar distance on the rotation of the femoral component in total knee arthroplasty. Researchers applied plain X-rays to measure the thickness of the medial and lateral posterior condylar cartilage fragments postoperatively, and evaluated the impacts of differences in cartilage thickness on final femoral component (FC) rotation. Between August 2015 and May 2017, 50 knees (19 men, 31 women) had undergone primary TKA to treat medial knee osteoarthritis at the hospital. They first assessed the distance between the posterior femoral condyles, resected the posterior condyle, and evaluated the thickness of the resected cartilage fragments. The impacts of differences were tested in cartilage thickness on final FC rotation of the residual medial and lateral cartilage with a trigonometric function. In cases where the FC external rotation angle is ascertained applying the posterior condyles as landmarks, this angle can be influenced by the intercondylar distance, particularly in Japanese women who have small physical stature. The outcomes imply that several anatomical landmarks should be referenced to achieve accurate FC rotation.