Development of a Bicondylar Surface for a Biomimetic Knee Joint capable of 3D Motion

The knee is a major joint that is capable of 6 degrees of freedom (DoF) motion. In this paper, we present a biomimetic design of a bicondylar knee joint capable of 3D motion. The development of bicondylar surfaces is limited by the absence of accurate condylar surface development methodologies. Hence, this paper proposes a novel methodology, to obtain accurate bicondylar surfaces. The proposed method is used to develop a physical knee joint model. This knee joint model is experimentally evaluated using a model lower limb test setup (replicating the ankle, knee, and hip). The squatting motion of a human is replicated using this test setup. The hip motion of a healthy male test subject is recorded via image capture, and the hip joint of the test setup is actuated to follow this path. The computational model of the knee joint is used to predict the expected motion path during squatting, and the experimental result is compared against it. The results show RMSEs of less than 2.4 mm and 5.78 mm for anterior-posterior and inferior-superior displacements, respectively. Hence, it shows that the proposed bicondylar surface development methodology can be used to develop a biomimetic knee joint capable of 3D motion.