Development and evaluation of a multi-axis biomechanical testing apparatus for knee

Abstract

This work describes the design and capabilities of a multi-axis biomechanical testing apparatus (MABTA). This loading frame was designed and developed to conduct in-vitro experiments on cadaveric human, animal and composite specimens while simulating loading poses taken from gait cycles, but applied in a quasi-static fashion. The purpose of this study was to develop a high standard apparatus with high repeatability for experimenting with composite and biological tissues. MABTA features three manually adjustable rotational axes: flexion-extension, varus-valgus and internal-external, as well as three translational load applications: proximal-distal, medial-lateral and anterior-posterior. MABTA can apply loads up to 4,448 N in the proximaldistal direction and 2,224 N in the medial-lateral and anterior-posterior directions. MABTA is capable of rotating to 100° flexion, 50° hyperextension, 20° in the varus-valgus direction and 30° in the internal-external direction. This apparatus can be used to evaluate human, animal and composite specimens in various physiological positions for validating finite element models, investigating anterior cruciate ligament fixations, patellar dislocation forces at various degree of flexion-extension and exploring the design of total knee prostheses. MABTA can provide good strain results and good repeatability between tests when testing with a third generation composite tibia and femur.