Tribology is the science of interacting surfaces in relative motion, and it studies friction, lubrication and wear.
The Tribology Laboratory, housed in the Department of Orthopedic Surgery, supports the medical industry in finding solutions related to lubrication mechanisms of joints, causes of articular cartilage degradation, friction and biocompatibility of orthopedic prostheses. Our aim is to improve the understanding of surface-surface interactions to reduce friction and wear of natural and artificial joints. This includes developing more durable bearing surfaces to extend their useful lifespan in patients and test new surface treatments for orthopedic implants.
The Tribology Laboratory is working closely with the Motion Analysis, the Computational Biomechanics, the Implant Pathology and the Spine Biomechanics laboratories.
The Tribology Laboratory was founded as a laboratory to provide biomaterials testing for medical research over 20 years ago. Over time our capabilities have expanded into a wide range of tests related to evaluating the joint implants. Our research can be grouped in the following areas:
Joint replacement procedures are currently carried out for hips, knees, shoulder, elbows, ankles and spinal disks. While most implants remain fully functional, with a survival rate of joint implants exceeding 90% after 17 years, nearly 10% of implants required revision surgery. Research on the lubrication and mechanical and chemical degradation are require to extend their implantation time.
Artificial joint implants are used to relieve pain and restore function in degenerated joints caused by disease, trauma or genetic condition. The primary function of implants is tribological as the bearing surfaces articulate under load. However, all implantable metal alloys are also susceptible to corrosion to a certain degree, depending on the metallurgical condition, residual or service stresses and surface treatment applied prior to implantation. Corrosion can reinforce tribological damage and vice versa, this is called tribocorrosion. Therefore, artificial joints are susceptible to the usual tribology issues of high friction, wear, corrosion and fatigue and these problems can contribute to failure and revision. The actual corrosion resistance of a material can only be proven by long-term clinical trials, but accelerated laboratory tests can be used to predict certain effects. Understanding the complex physical and chemical interactions between contact surfaces and the surrounding body fluids is now an area of research in artificial joint tribology.
The role of interfacial reactions in the degradation of joint surfaces and junctions by tribocorrosion is studied in the laboratory. We have made substantial contributions to tribocorrosion research and to the understanding of synergies and antagonisms between wear and corrosion in the medical field. We remain active in all aspects of tribocorrosion research. Our activities include the following areas of interest:
Polyethylene components are used as liners and bearing surfaces for joint replacements. The Ultra High Molecular Weight Polyethylene (UHMWPE) is the dominant bearing material of choice in Total joint Arthroplasty for its tribological and mechanical properties that can ensure long in vivo service. Cross-linked UHMWPE greatly reduced wear, and particle biocompatibility without causing catastrophic ruptures and tissue reactions.
New and promising materials, like crosslinked and vitamin E charged polyethylenes, are considered safe but innovative and are therefore handled cautiously. Many in vitro tests and several in vivo demonstrations have confirmed the validity of these materials, but it is important to remember that they do not yet have long-term clinical histories. In the Tribology Laboratory, we are investigated the role of debris of crosslinked polyethylene, the quantity and reactivity of which are still to be elucidated and the long-term behavior of cross-linked material. The accurate documentation of the relative wear performance of well-characterized contemporary and historic polyethylene is important both in the projection of the future success of polyethylene-based implant treatment and in the consideration of alternative bearing types. Our interest covers the following topics:
Hemiarthroplasty is a procedure to replace degenerative and non healthy articular cartilage by implant material that will articulate against it. It is a surgery less invasive than total joint arthroplasty and preserve the cartilage and bone capital of patients.
The friction and lubrification of hemi implants articulated against articular cartilage is important to be investigated in laboratory in order to extend their lifetime and therefore postpone the implantation of total implant. We have the ability to conduct non stationary mechanical stimulation of live cartilage and complement it with biological analyses to understand the in vitro reaction of cartilage. Our research interests are to:
The preservation of articular cartilage is highly dependent on maintaining its organized architecture. A fundamental understanding of articular cartilage mechanics is essential for aiding clinicians in enhancing the longevity of healthy joints and rehabilitating injured joints.to the development of promising treatment.
Articular or hyaline cartilage is a thin layer of specialized connective tissue that covers the ends of bones. Its primary function is to provide low friction and wear under normal function and to facilitate the transmission of loads to the underlying subchondral bone. When hyaline cartilage begins to degenerate with age, or when it is damaged by injury, the tissue may be overstressed. The injury and resulting loss of function can increase friction, signal further matrix degeneration and initiate osteoarthritis (OA).
Unlike most tissues, articular cartilage is devoid of blood vessels, nerves, or lymphatics. It is composed of a dense extracellular matrix (ECM) with a sparse distribution of highly specialized cells called chondrocytes. The ECM is principally composed of water, collagen, and proteoglycans, with other non-collagenous proteins and glycoproteins present in lesser amounts. Together, these components help to retain/attract water, which is critical to maintain its unique mechanical properties.
From a mechanical point of view, articular cartilage is a composite of materials composed of a fluid phase (mainly water) and a solid phase (ECM). Cartilage is considered a permeable, viscous and elastic material. Due to its elasticity, articular cartilage gives rise to deformations, but always returns to its original shape, and it combines a remarkably long life with low friction. Under dynamic loads, a sort of pumping effect occurs. This leads to an increase in volume and also causes an increase in tension in the collagen fibers, which increases the elasticity of the tissue. Collagen fibers provide good tensile strength. The water-proteoglycan compounds provide compressive strength and elasticity.
The biological and mechanical properties of articular cartilage are very complex and vary from area to area depending on its composition (water concentration, proteoglycan content, collagen fibers orientation). The preservation of articular cartilage is highly dependent on maintaining its organized architecture. A fundamental understanding of articular cartilage mechanics is essential for aiding clinicians in enhancing the longevity of healthy joints and the development of promising treatments for injured joints.
Our group is investigating the unique properties of articular cartilage such as the intrinsic viscoelasticity, the wear resistance and the stiffness. The current interesting research area are focusing on:
Infection on and around an artificial implant prosthesis, such as knee or hip replacement surgery can be a devastating and costly complication. It is amongst the leading causes of revised surgery and poor surgical outcomes in orthopedics.
Biomaterial-associated infections are a result of microorganisms adhering to a medical implant or device. Following adherence of the microorganism to the implant or medical device, biofilm formation can occur. Development of biofilm on an implant surface makes these infections highly resistant to immune host defense and antimicrobials. This resistance makes these biomaterial-associated infections difficult to treat. These types of infections can be challenging to manage and result in:
Our team focuses on methods of prevention and treatment of periprosthetic joint infection (PJI), which is infection on and around an artificial implant prosthesis, such as those used in knee or hip replacement surgery. PJI can be a devastating and costly complication of joint replacement surgery and is amongst the leading causes of revised surgery and poor surgical outcomes in orthopedics.
Building on the experience of conducting sterile lab tests and corrosion research, our group investigates the following areas:
Orthopaedic Research Society Annual Meeting, Dallas, TX, February 2023
7th World Tribology Congress 2022, Lyon, France
33rd Annual Congress of International Society for Technology in Arthroplasty, Maui, HI, USA
Our team consist of experts in materials, mechanics, chemistry, and biology.
Professor Wimmer is the Grainger Director of the Rush Arthritis and Orthopedics Institute in Chicago and serves as the Associate Chairman for Research in the Department of Orthopedic Surgery at Rush University Medical Center. He holds conjoint appointments in the Departments of Rheumatology, Anatomy and Cell Biology, as well as Biomedical Engineering at the University of Illinois at Chicago.
Dr. Wimmer received his diploma in Mechanical Engineering from the Technical University of Munich, Germany. After a post-graduate year in Chicago, Dr. Wimmer continued his education in Germany and earned a doctorate in Biomechanics at the Hamburg University of Technology. Before joining Rush in 2001, he spent four years at the AO Research Institute in Davos, Switzerland.
Dr. Schmid is a Biochemist and Cell Biologist. His research career has focused primarily on biomarkers in cartilage. He discovered type X collagen and showed it is a biomarker for hypertrophic chondrocytes at the interface of calcified and uncalcified cartilage. The synthesis of type X collagen is induced by Ca<sup>+2</sup> ions. He also identified superficial zone protein (lubricin) as a biomarker at the surface of articular cartilage where it is synthesized by superficial zone chondrocytes. It acts as a major lubricant in synovial joints by lowering the coefficient of friction at this surface. Its synthesis is induced by TGFa released as one tissue rubs against another.
Amandine Impergre is the Tribology Laboratory Supervisor in the Department of Orthopedic Surgery at Rush University Medical Center.
Her research areas include corrosion, tribocorrosion and biocompatibility of metal biomaterials, with a focus on preventing accelerated chemical degradation and cytotoxicity of cartilage. She completed her Bachelor of Science degree in Physics and Chemistry and her Master in Corrosion and Materials engineering at the University of La Rochelle, in France. She graduated first in her class with the highest GPA. She pursued her Ph.D. at MATEIS Laboratory in INSA of Lyon, France under the mentorship of Dr. Normand, a preeminent electrochemist scientist who is world-renowned for the corrosion characterization of metals and particularly in tribocorrosion.
Dr. Impergre completed her postdoctoral studies at Rush investigating the in vitro biotribological properties of the Pyrolytic Carbon implant (InSpyre), a non-metallic shoulder interposition implant, which minimize the replacement of healthy tissue in the joint. Since joining Rush in 2019, Dr. Impergre has brought knowledge of electrochemistry in the biomedical field, and lead biocompatibility assays of cartilage.
John L. Hamilton is an Instructor in the Department of Orthopedic Surgery at Rush. He received his MD, PhD, and postdoctoral training at Rush University Medical Center. During this training, he was awarded an NIH F31 Predoctoral Fellowship in the Department of Biochemistry at Rush and investigated underlying mechanisms of osteoarthritis pathology as well as development of novel osteoarthritis treatments.
As an NIH T32 Postdoctoral Fellow in the Departments of Orthopedics, Internal Medicine, and Anatomy and Cell Biology at Rush, he investigated methods of immunomodulation to prevent periprosthetic joint infection. Current research efforts include translational projects in the fields of periprosthetic joint infection, degenerative joint disease, inflammation and immunology, and COVID-19.
Mohammed is a postdoctoral research fellow in the Department of Orthopedic Surgery at Rush. He is a veteran who received his MD degree from St. George’s University School of Medicine in 2022, and his Chemistry Bachelor’s Degree from the University of Illinois at Chicago in 2014.
While still in medical school, he was awarded an NIH T32 Fellowship research training grant in joint health in the Department of Orthopedic Surgery at Rush. His past employemnt as an automotive mechanic provided him with extensive experience in mechanics. He also worked in the biochemisty department at the University of Illinois at Chicago. Current research work includes wear simulation and modeling, and investigating the rheological properties and behavior of bovine knee cartilage to help in understanding the mechanisms and progression of osteoarthritis, which is key for prevention and for optimal design of replacements
Adrienn Markovics MD, PhD is an Assistant Professor at the Department of Orthopedics. Her area of interest includes immunology, orthopedics and pharmacology. She holds a medical degree from the University of Pecs, Hungary, where she was awarded a PhD scholarship in pharmacological sciences. Dr. Markovics joined Rush University Medical Center in 2014 and investigates joint-related pathophysiology such as periprosthetic joint infection and the autoimmune rheumatoid arthritis. She is a member of The American Association of Immunologists and the Orthopaedic Research Society. She has been published in several peer-reviewed journals, her complete list of bibliography can be found at this link.
Alfons Fischer received his Dipl.-Ing. degree in mechanical engineering from the Ruhr Universität Bochum, Germany in spring of 1980. He completed his Dr.-Ing. (Ph.D.) and Priv.-Doz. (Private Lecturer) degrees in materials science and engineering from the same university in summer of 1984 and in fall of 1992, respectively.
From 1992 to 1996, he was head of quality management as well as vice-head of the center of analyses and testing of NuTech GmbH, Neumünster, Germany; a company providing laser-processing technologies, materials testing, and failure analyses.
Since 1996, he was a full professor for materials science and engineering at the University of Duisburg-Essen in Germany from which he retired February 2019. His research (fundamental and applied) as well as his services (materials development and testing, failure analyses, expert reports) focus on fatigue, wear and corrosion of metals and metal-matrix composites with institutional and industrial partners in mechanical, production, automotive, off-shore, tooling, and biomedical engineering.
Since 2005, he is a visiting researcher at Rush University Medical Center, Dpt. of Orthopedic Surgery, Chicago IL, USA and since March 2019 also at the Max-Planck-Institut für Eisenforschung, Duesseldorf, Germany. He serves as co-editor-in-chief of the archival journal WEAR since Jan. 1st 2020. He has published more than 240 papers and co-authored five books.
Dr. Koya is an orthopedic surgeon who has specialized in knee surgery in Japan. While working at the Showa University Koto Toyosu Hospital and Fujigaoka Hospital, he treated knee injuries and osteoarthritis by performing joint repairs such as ligament reconstructions and meniscus repairs and joint preserving surgeries such as osteotomies and arthroplasty procedures (TKA, UKA). Since April 2022, he has joined the Tribology and Motion Analysis Laboratories at Rush University as a Postdoctoral Trainee under Dr. Wimmer. His current research focuses on the influence of biomaterials articulating against cartilage to improve hemiarthroplasty and studying TKA function during recreational activities such as golf.
Francesca de Vecchi is a Biomedical Engineering graduate student enrolled in a double degree program between University of Illinois at Chicago and Politecnico of Milan. She achieved her bachelor’s degree in Biomedical Engineering at Politecnico of Milan and continued her studies there with a master’s degree focused on Biomechanics and Biomaterials.
In August of 2021, she moved to University of Illinois Chicago to complete the double degree program in the US. There, she joined the Tribology Laboratory at Rush University to work on her thesis, which she defended in December of 2022. Her research focuses on the tribological and mechanical characterization of bovine articular cartilage after chemical treatments to study the influence of divalence ions on the tissue.
Name | Period | Academic School | Research Project |
---|---|---|---|
Catherine Yuh |
2015-2020 |
Rush Univ., Biotechnology |
Investigation of articulation-induced articular cartilage stiffening |
Filippo Cinotti |
2019-2020 |
Politecnico di Milano, Italy |
Assessment of TiN coatings for TJR |
Lorenzo Girotto |
2019-2020 |
Politecnico di Milano, Italy |
Surface modification of titanium to combat PJI |
Jacqueline Simon |
2013-2019 |
Rose-Hulman Institute of Technology |
Functional assessment of bicruciate total knee replacement |
Chris Knowlton |
2009-2019 |
Univ. of Illinois at Urbana-Champaign |
Volumetric wear determination of retrieved knee implants |
Taylor Holcomb |
2016-2018 |
Cornell University |
Full-scale design of a novel tribo-corrosion cell culture system |
Steven Mell |
2013-2018 |
University of Illinois at Chicago |
A computational framework for parametric evaluation of TKR wear |
Robert Trevino |
2011-2016 |
Pace University |
Role of mechanical wear in healthy cartilage |
Name | Period | Academic School | Research Project |
---|---|---|---|
Yigiterkut Canpolat |
2014-2015 |
University of Duisburg-Essen |
Knee wear tests according to two different ISO standards |
Ryan Freed |
2013-2015 |
Clemson University |
Translation motion analysis data to TKR simulator for walking and stair activities |
Christoph Daniels |
2013-2014 |
University of Duisburg-Essen |
Patient specific TKR wear simulation and cross-validation with retrieved polyethylene liners |
Elmira |
2013-2015 |
Shahid Bahonar Univ of Kerman |
Volumetric wear assessment and characterization of tibial inserts |
Johnny Dufils |
2013-2014 |
Ecole Centrale Lyon |
Design and setting up of a corrosion fretting apparatus to investigate the effect of molybdate ions |
Robert Cichon |
2011-2012 |
University of Duisburg-Essen |
Design of a new bioreactor test rig for tribo-corrosion studies |
Bojan Mitevski |
2011-2012 |
University of Duisburg-Essen |
Wear analysis and patient data correlation of cruciate retaining total knee replacements |
Diego Orozco |
2006-2012 |
University of Colima, Mexico |
Activities of Daily Living and Their Impact on Total Knee Replacement Wear |
Jonathan Stoia |
2010-2011 |
University of Illinois at Chicago |
Cartilage articulating system as a wear benchmark for artificial joint replacement |
Bryan Schlink |
2009-2011 |
Purdue University |
Gait biomechanics and disease severity in hip osteoarthritis |
Patrick Werner |
2010-2011 |
Technical University of Munich |
Development and evaluation of gait retraining for patients with knee osteoarthritis using telemetric shoe insoles with tactile and audio feedback |
Felix Liedtke |
2010-2011 |
University of Essen-Duisburg |
Generation of CoCr mechanically mixed zones and the tribological behavior under reverse sliding |
Christian Schoss |
2010-2011 |
University of Duisburg-Essen |
Wear tests of a surface structured CoCrMo-alloy |
Name | Period | Academic School | Research Project |
---|---|---|---|
Chris Ferrigno |
2011-2015 |
Medical College of Georgia |
The effect of bio feedback on knee adduction moment |
Yuen-Ying Valentina Ngai |
2006-2010 |
University of Manitoba; |
Assessment of in vivo gait patterns on wear of total knee replacements |
Yasha Dwivedi |
2007-2009 |
Vishwakarma Institute of Technology |
The influence of proteins on the wear of UHMWPE |
Idubijes Rojas |
2007-2009 |
University of Illinois at Chicago |
Dynamic surface EMG of TKR patients: |
Luis Antonio Gallardo |
2007-2009 |
Instituto Tecnologico y de Estudios Superiores de Monterrey |
Oxidative stability of ultra-high molecular weight polyethylene doped with europium stearates |
Vivek Shekhawat |
2004-2009 |
Nagpur University, India; |
Influence of Kinematics on Mechano-Biological Response of Articular Cartilage – An in vitro Investigation |
Thorsten Schwenke |
2003-2008 |
Hamburg University of Technology |
Wear of the Tibial Polyethylene Component in Total Knee Replacements - The Significance of Sliding Velocity During Gait |
Richard Kang |
2006-2007 |
Northwestern University |
A Controlled Laboratory Study of the Biologic Effects of Repeated and Varying Loads on Osteochondral Grafts |
Andrea Swanson |
2005-2007 |
Northwestern University |
In vivo methods for locating the tibio-femoral contact pathway in TKR during gait |
Christiane Schulz |
2006-2007 |
Univ. Duisburg-Essen |
Fretting of UHMWPE against stainless steel |
Robin Pourzal |
2005-2006 |
Univ. of Duisburg-Essen |
Determination of polyethylene wear location and volume in well functioning acetabular cups |
Diego Orozco |
2004-2006 |
University of Colima, Mexico |
An artificial neural network approach to understand wear of TKR |
Laura Thorp |
2002-2006 |
University of Scranton, PA |
The relationship between structure and function in knee osteoarthritis: a mechanical perspective utilizing gait analysis |
Sidhart Nileshwar |
2003-2005 |
University of Mumbai |
Relating surface damage of articular cartilage to local mech properties |
Maximilian Müller |
2004-2005 |
Tech Univ. Munich |
The role of biomechanical forces on cell deformation |
Sascha Müller |
2004-2005 |
Tech Univ Chemnitz |
Cartilage stiffness and related stress during impaction grafting of osteochondral tissue |
Rachna Sah |
2004–2005 |
MGM College, Mombai, India |
The role of biomechanical forces on cell deformation (Bioengineering) |
Laura Borgstede |
2002-2004 |
Colorado State University |
Parametric analysis of wear mechanisms in total knee replacement |
Priyanka Paul |
2002-2004 |
Univ. of Illinois at Urbana-Champaign |
Wear characterization of retrieved total knee implants |
Bill Nechtow |
2002-2004 |
Univ. of Illinois at Urbana-Champaign |
Activity of total knee replacement patients |
Tamara Pylawka |
2003-2004 |
University of Illinois |
Role of Nitric Oxide in Metabolic Function of Cold Preserved Allograft Cartilage |
Mozammil Hussain |
2001-2003 |
University of Chandigarh |
Stresses in polyethylene tibial inserts for two walking patterns using FEM |
Staff:
Name | Period | Role |
---|---|---|
Spencer Fullam | 2016-2021 | Laboratory Supervisor |
Carol Pacione | 2013-2016 | Laboratory Supervisor |
Tobias Uth | 2009-2013 | Laboratory Supervisor |
The tribology laboratory is equipped with a full range of friction/wear tests and joint simulators that simulate the forces and fluid environment of joints. Researchers also have the ability to perform electrochemical and tribocorrosion tests to study the corrosion resistance of orthopedic implants. Various surface characterizations and analyses are available to complete the evaluation of the in vivo behavior of orthopedic implants and the failure of joints in the human body.
The tribology laboratory also has the capability to perform friction tests in contact with cells/tissues such as cartilage explants. The biocompatibility or biological response of tissues undergoing mechanical testing (micro-, nano- and macro-) is assessed and complemented by a variety of biochemistry techniques.
Several tribometers are available to evaluate the resistance to wear and corrosion of orthopedic implants. Direct contact with cell cultures is possible thanks to a tribometer housed in an incubator.
Detail of the fretting corrosion chamber.
Tribocorrosion bioreactor.
Six stations pin-on-discs apparatus.
Knee joint simulator with four stations.
Mechanical view of the knee joint simulator.
Example of a knee implant.
Custom cartilage damage impactor.
Custom cartilage shear impactor housed in an incubator.
Modular compact Rheometer.
Our group has the infrastructure on site, such as a Biohazard Safety Level 2 room. This room is located on the 7th floor of the Cohn Research Building. The Cohn Research Building is suitable to perform both microbiological and rodent experiments. Our equipment includes but is not limited to the following:
Basic laboratory equipment are also available such as ultrasound cleaner, balances, magnifying glasses, pH-meter, centrifuge, water purification, chemical fumehoods, biosafety cabinet, sputter coater for sample preparation, etc.
Ti-950 Nanoindenter
Fourier Transform Infrared (FTIR) spectrometer
Confocal Raman Microscope
3D Surface Profiler
Scanning electron microscope (SEM)
We gratefully acknowledge funding from philanthropy, industry, foundations, as well as federal agencies, including the National Science Foundation and the National Institutes of Health.
Department of Orthopedics
Rush University Medical Center
1611 W. Harrison St, Suite 204-205
Chicago, IL 60612
The group is always looking for PhD students and post-doctoral researchers. If you are interested in joining us and would like to find out about any current vacancies please contact Dr. Wimmer (Markus_A_Wimmer@rush.edu). If you are interested in collaborating with us or joining our research team, please get in touch with a relevant staff member.