Over the past 2 decades our understanding of the anatomy and biomechanics of the knee joint has dramatically increased. The translation of this knowledge into clinical practice has greatly improved athletic training and medical treatment when injury occurs. Advances in imaging techniques have played a role in this improvement. The next step for imaging is to move beyond merely providing morphology and to assess the functional mechanics of the knee. This article focuses on the biomechanics of the femorotibial joint and its relevance to imaging.