Finite Element Analysis of Total Knee Arthroplasty

Total knee arthroplasty (TKA) has become one of the most common operations in all of medicine, with an average of 966,000 performed annu - ally in the United States. Since its introduction in 1968, TKA surgical techniques and implant designs have improved to increase prosthesis longevity. However, aseptic loosening of TKA components continues to be the most common reason for revision surgery. Ideal implant characteristics, which minimize stress shielding have yet to be determined. The purpose of this study was to investigate how implant design parameters including fixation technique, tibial stem geometry, cement stiffness, and implant-bone frictional interface affect stress shielding within the tibia, and to determine the optimal combination that minimizes this effect. A CT scan of a tibia was used to simulate multiple tibial stem configurations for finite element analysis in ABAQUS. Stress shielding was calculated by using the average minimum principal stress at interval cuts along the length of the tibia. We found that short, fully-cemented stems, high-stiffness hybrid cemented stems, low-stiffness for fully-cemented stems, and a sliding friction interface to be ideal.