Combined Experimental and Statistical Model to Understand the Role of Anatomical and Implant Alignment Variables in Guiding Knee Joint Motion

Kinematics variation is the inheritant part of the joint mechanics; factors such as patient anatomy, joint loading and implant alignments are all variable in nature. Improvement in the design of orthopedic implants requires a good understanding of the roles that anatomy and implant alignment plays in guiding joint motion. The proposed research focuses on describing the relationship of various anatomical and implants alignment factors with the tibiofemoral kinematics during passive envelope and walk. An experimental method to manually assess passive knee envelope was described. Principal component (PC) model was developed for the varus-valgus (V-V), internal-external (I-E) and anterior-posterior (A-P) envelope using twenty-one native cadaveric knees and the mode of envelope variations were identified. Subsequently, gait simulation was run on seventeen knees using the Kansas Knee Simulator. Effects of variation in V-V and I-E envelope and anatomy on the envelope along with the gait kinematics were assessed using another PC model. Same PC model was used to understand the effect of anatomy and the implant alignment features on the post-TKA envelope and gait kinematics