John D. DesJardins, Ph.D.
Assistant Professor in Bioengineering and
Director of Bioengineering Abroad Programs
Director of Bioengineering Abroad Programs
B.S. Mechanical Engineering (Biomedical Option), 1992,
Carnegie-Mellon University
M.S. Mechanical Engineering (Biomechanics Emphasis),
1994, University of Pittsburgh
Ph.D. Bioengineering (Biomaterials Tribology Emphasis),
2006,
Clemson University
Carnegie-Mellon UniversityM.S. Mechanical Engineering (Biomechanics Emphasis),
1994, University of PittsburghPh.D. Bioengineering (Biomaterials Tribology Emphasis),
2006,
Clemson UniversityResearch Interests
Orthopaedic Biomechanics, Biomaterials Tribology,
Total Joint Replacement Simulation
Engineering and Machine Design
Total Joint Replacement Simulation
Engineering and Machine Design
Email:
Office: 215 Rhodes Research Center
Phone: 864.656.4178
Office: 215 Rhodes Research Center
Phone: 864.656.4178
Honors, Awards, and Professional Activities
1995 Johns Hopkins University, Department of Orthopaedic Surgery, Biomechanics Research Laboratory, Researcher of the Year1996 Johns Hopkins University, Department of Orthopedics, Travel Award Participant2000 Sigma Xi, National Research Honor Society2001 Clemson University, Bioengineering Graduate Seminar Series, Best Presenter Award2005 Alpha Epsilon Lambda, National Graduate Student Honor Society2006 Georgia Institute of Tech., Microelectronics Research Center, Trailblazer Scholarship RecipientSociety Memberships:
American Society of Mechanical Engineers (ASME) American Society of Biomechanics (ASB)Society For Biomaterials (SFB)Orthopaedic Research Society (ORS)Society of Tribology and Lubrication Engineering (STLE)Current Research
Total Joint Replacement Simulation
Total joint replacement simulation is an experimental method whereby researchers hope to replicate the mechanics of artificial knee and hip joints in the laboratory. During daily activity, total joint replacement materials and wear surfaces are subjected to a variety of forces, motions and/or environmental conditions that are difficult to quantify within the patient. Total joint replacement simulation attempts to replicate these in-patient conditions in a controlled laboratory setting so that important measures of implant performance such as implant motions, stresses, failure modes, and long term bearing wear can be accurately quantified. Clemson University is proud to maintain an active research program in the area of knee joint replacement simulation and is one the few universities in the world to conduct peer-reviewed research on Instron/Stanmore force-controlled knee joint simulators. Current research in this area concentrates on: 1) the development of more descriptive loading and displacement simulation profiles for the more accurate assessment of the activities of daily living, 2) the assessment of novel implant designs, materials, and surface treatments for the enhancement of total joint function, 3) the development of new sterilization technologies for the treatment of biomaterials, and 4) the investigation of novel lubricant formulations for the simulation of total joint replacement wear processes.
Biomaterials Tribology
Hemi-arthroplasty is an orthopaedic procedure whereby only one of the rubbing articular surfaces is replaced with a biomaterial. At Clemson University, recent research in this area has led to the development of an in vitro experimental model for the tribological evaluation of cartilage replacement biomaterials. Small-animal articular cartilage specimen are being investigated as experimental pairings with novel polymer bearing materials to evaluate measures of tribologic importance. Some of the key objectives this research focus are: 1) to design experimental fixtures and testing methods to utilize small-specimen articular cartilage constructs as articulating implements during wear testing, 2) to enable the measurement of the coefficient of friction between the contacting polymers and articular cartilage during multi-directional sliding motions, and 3) to investigate the damage mechanisms of the cartilage/bio-material wear surfaces as a result of wear testing. Thus far, research efforts have been successful in establishing a reproducible test-bed from which future candidate cartilage replacement biomaterials can be evaluated. Experimental studies have also been able to elucidate a dependant wear relationship between the cartilage/material surfaces, similar to the in vivo case. Harder hemi-arthoplasy materials have been shown to possess good wear resistance but do so at the expense of the articular cartilage surface, damaging the articular cartilage and increasing the wear potential of the system. Softer hemi-arthoplasy materials preserve articular cartilage integrity, but ultimately possess shorter service lifetimes. Further research is needed to optimize the hemi-arthroplasty material properties to optimize this delicate tribological union between cartilage and material. Experimental variables that continue to be of interest in this research include articular geometry, uniformity of articular thickness across in vivo specimen, wear-testing pathway, and lubricant conditions during testing.
Orthopaedic Biomechanics
Work in the area of orthopaedic biomechanics at Clemson University focuses on the quantification of musculoskeletal mechanics and the development of novel techniques for the treatment of bone and joint conditions. Current research efforts focus on: 1) the assessment of clinically successful and novel fracture fixation devices, 2) the quantification of joint mechanics for the elucidation of force and motion envelopes within the activities of daily living, and 3) the treatment of the arthritic condition utilizing conservative cartilage interventions, joint lubricant visco-supplementation, joint resurfacing with novel biomaterials, and cutting-edge total joint replacement procedures.
Engineering and Machine Design
The laboratory assessment of the orthopaedic condition requires the design and fabrication of experimental testing fixtures and complex simulation hardware. Key to this effort is the development of research methods that reproduce or replicate the mechanical conditions of force or motion that occur within the living system. Machine design of these bioreactors or simulators requires the detailed study of the model of interest followed by the meticulous design and fabrication of fixtures, hardware, and software for the implementation of experimental methods. Work at Clemson University has focused on the development of wear-testing methodologies and systems for the elucidation of multi-axis motion wear processes in orthopaedic biomaterials. The MAX-Shear (Multi-Axis Cross Shear) wear-testing machine is one such wear-testing platform and was developed at Clemson University to address the experimental observation that multi-directional motions on total joint replacement materials accelerate bearing material wear. This is a significant concern to the total knee joint industry because these devices have been shown to possess this multi-directional bearing motion, and the number of total knee procedures is significantly increasing world-wide. Industrially sponsored research on this testing platform has provided further insight into the mechanisms of accelerated implant wear and assisted in the quantification of wear mechanisms that limit the longevity of total joint devices.
Recent Publications
J. DesJardins - Curriculum Vitae
M.R. Gevaert, M. LaBerge, J.M. Gordon, J.D. DesJardins , The Quantification of Physiologically Relevant Cross Shear Wear Phenomena on Orthopaedic Bearing Materials Using a Novel Wear Testing Machine, Journal of Tribology, Vol. 127, No. 4, pp. 740-749, October 2005.
A. Aurora, J.D. DesJardins, P.F.Joseph, M. LaBerge, Effect of Lubricant Composition on the Fatigue Properties of Ultra High Molecular Weight Polyethylene (UHMWPE) For Total Knee Replacement, Proceedings of the Institute of Mechanical Engineering, Part [H], 220(4): pp. 541-51, 2006.
J.D. DesJardins, A. Aurora, S.L. Tanner, T.B. Pace, D. M. LaBerge, Development of a clinically relevant TKR simulator lubricant, Proceedings of the Institute of Mechanical Engineering, Part [H], 220(5), pp. 609-623, 2006.
L.M. Gustafson, J.D. DesJardins, L.C. Benson, M. LaBerge, Quantification of Dynamic Tibiofemoral Contact in a Total Knee Replacement During Simulated Daily Activity. MUSC Orthopaedic Journal, Vol. 9, pp. 12-19, June 2006.
H. Haider, P.S. Walker, J.D. DesJardins, G.W. Blunn, Effects of Pateint and Surgical Alignment Variables on Kinematics in TKR Simulation Under Force-Control. Journal of ASTM International, Vol. 3, No. 10, pp. 1-14, Nov/Dec 2006.
