Under the direction of Dr. Guoan Li and Dr. Harry Rubash, the arthroplasty group works closely with clinicians in the Adult Reconstructive Surgery Service to conduct basic science research for the advancement of the current state of knee joint arthroplasty. We use a combination of advanced imaging techniques (magnetic resonance imaging + bi-planar fluoroscopy) and custom computational tools, to study various aspects of knee biomechanics in the healthy, diseased and reconstructed knees.
Using these techniques we showed that the knees of patients with osteoarthritis show a distinctly different kinematic pattern compared to those in healthy subjects. However, this change in the kinematics patterns of the knee following severe joint disease is not restored to normal following conventional arthroplasty. Therefore, the group continues to explore opportunities to improve current implant design and surgical procedures, to enable the improvement of functional outcome following knee joint arthroplasty.
In another study we collaborated with researchers from the Scripps Clinic in La Jolla, CA to investigate the dynamic forces and articular contact patterns experiences by the knee joint during daily activities. This was accomplished using specially design knee replacement implants with embedded force sensors and dynamic fluoroscopy.The study provided critical data for more accurate reproduction of in vivo loads and articular motion patterns in wear simulations and finite element models. This in turn with help advance our understanding of factors limiting longevity of knee replacement implants such as component loosening and wear, and enable improved designs.
Implant model matched to fluoroscopic image
Net force within knee joint (brown line) as subject rises from and sits in a chair. BW = body weight
Determination of articular contact
- Yue B, Varadarajan KM, Moynihan AL, Liu F, Rubash HE, Li G. “Kinematics of Medial Compartment OA Knees before and after Total Knee Arthroplasty”, J Orthop Res, 2010.
- Varadarajan KM, Rubash HE, Li G. “Are Current TKA Implants Designed to Restore Normal Trochlear Groove Geometry?”, J Arthroplasty, 2010.
- Varadarajan KM, Freiberg AA, Gill TJ, Rubash HE, Li G. “Relationship Between Three- Dimensional Geometry of the Trochlear Groove and In vivo Patellar Tracking During Weight-Bearing Knee Flexion”, J BiomechEng, 132(6), pp 8-1:8-7, 2010.
- Varadarajan KM, Gill TJ, Freiberg A, Rubash HE, Li G. “Patellar Tendon Orientation and Patellar Tracking in Male and Female Knees”, J Orthop Res, 28 (3), pp 322-8, 2010.