Markus A Wimmer's research while affiliated with University of Illinois at Chicago and other places

Publications (236)

Article
This study investigated the accuracy of the Insole3 wireless shoe device in estimating several clinically useful spatiotemporal parameters (STPs). Eleven subjects walked at slow (0.8-1.0 m/s) and moderate-paced (1.2-1.4 m/s) speeds. Data were simultaneously recorded using the Insole3 and an industry-standard, three-dimensional motion capture (MOCAP...
Article
The presented study dealt with the experimental analysis of friction and lubrication mechanism observed with fluorescent microscopy in total knee replacement represented by CoCrMo wheel and PMMA plate. Model synovial fluid with marked constituents was used as test lubricant. The experiments investigated three main parameters. Slide-roll-ratio (SRR)...
Article
Our objective was to quantify the effect of ACL transection on dynamic knee joint contact force distributions during simulated gait. Given the prevalence of medial compartment osteoarthritis in un-reconstructed ACL ruptured knees, we hypothesized that changes in contact mechanics after ACL transection would be most prevalent in the medial compartme...
Article
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Pressure-detecting insoles such as the Insole3 have potential as a portable alternative for assessing vertical ground reaction force (vGRF) outside of specialized laboratories. This study evaluated whether the Insole3 is a valid and reliable alternative to force plates for measuring vGRF. Eleven healthy participants walked overground at slow and mo...
Chapter
A novel approach to address the clinical issue of cell response to wear and corrosion debris from metal orthopedic implants consists of combining cell culturing with wear and corrosion debris generation. A biotribometer equipped with a three-electrode electrochemical chamber operates inside a CO2 incubator. Cells are cultured at the bottom of the c...
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There is a need for treatments to reduce coronavirus disease 2019 (COVID-19) mortality. Alpha-2 adrenergic receptor (α 2 AR) agonists can dampen immune cell and inflammatory responses as well as improve oxygenation through physiologic respiratory parameters. Therefore, α 2 AR agonists may be effective in reducing mortality related to hyperinflammat...
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The performance of CoCrMo alloy in orthopaedic implants may be unfavourably affected by hyaluronic acid (HA) in synovial fluid. In this study, the authors aimed to understand the interactions between HA and CoCrMo using dedicated electrochemical experiments and surface analyses. A sequence of electrochemical measurements (open-circuit potential, li...
Article
Currently, preclinical mechanical wear testing of total knee replacements (TKRs) is done using ideally aligned components using standardized TKR level walking under either force or displacement-control regimes. To understand the influence of implant alignment and testing control regime, we studied the effect of nine component alignment parameters o...
Article
CoCrMo-alloys are well-established biomaterials used for orthopedic joint replacement implants. However, such alloys have been associated with clinical problems related to wear and corrosion. A new generation of austenitic high-nitrogen steels (AHNS) has been developed for biomedical applications. Here, we have addressed influences of hyaluronic ac...
Article
Bone microarchitectural parameters significantly contribute to implant fixation strength but the role of bone matrix composition is not well understood. To determine the relative contribution of microarchitecture and bone matrix composition to implant fixation strength, we placed titanium implants in 12-week-old intact Sprague-Dawley rats, Ovariect...
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Nickel‐free, high‐nitrogen austenitic steels (AHNS) have been introduced for biomedical applications, with encouraging results in terms of mechanical and corrosion properties. Here, we tested the corrosion resistance of a nickel‐free high nitrogen steel (FeCrMnMoN0.9) in bovine serum solutions containing 0 or 3 g/L hyaluronic acid (HA), and 0, 3, o...
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Total knee arthroplasty is on the rise worldwide. Despite its success, revision surgeries are also increasing. According to the American Joint Replacement Registry 2020, 3.3% of revision surgeries are due to wear, and 24.2% are due to mechanical loosening. The combination of shear stresses and wear particles occurring at the bone/implant interface...
Article
Biomechanical influences play a fundamental role in the structural, functional, and biosynthetic properties of articular cartilage. During physiologic joint loading, the contact area between two surfaces migrates due to the primary and secondary motions of the joint. It has been demonstrated that a migratory contact area plays a critical role in re...
Article
Contemporary hip implants feature a modular design. Increased reported failure rates associated with the utilization of modular junctions have raised many clinical concerns. Typically, these modular interfaces contain circumferential machining marks (threads or microgrooves), but the effect of the machining marks on the fretting-corrosion behavior...
Article
Fretting corrosion of biomedical taper junctions has raised concerns about adverse local tissue reactions. Particularly for CoCr29Mo6/TiAl6V4 couplings the exact mechanisms and interactions are not fully understood. Proteinaceous tribomaterial within such contact interface may act as boundary lubricant and hindering corrosive attack. In this contex...
Article
This contribution is aimed at the detailed understanding of lubrication mechanisms within total knee replacement. While Part I is focused on the experimental investigation, Part II deals with the development of a predictive numerical model. Here, a knee simulator was used for direct optical observation of the contacts between a metal femoral and a...
Article
Total knee replacements are an effective surgical treatment to restore the function of the knee. For an adequate design, knowledge about stresses and lubrication conditions is vital. Part II proposes a fully-coupled transient 3D model for the soft elastohydrodynamically lubricated contact based upon the generalized Reynolds equation and Finite Elem...
Article
As a mechanoactive tissue, articular cartilage undergoes compression and shear on a daily basis. With the advent of high resolution and sensitive mechanical testing methods, such as micro-and nanoindentation, it has become possible to assess changes in small-scale mechanical properties due to compression and shear of the tissue. However , investiga...
Article
Total knee arthroplasty has become a routine procedure for patients suffering from joint diseases. Although the number of operations continuously increases, a limited service-life of implants represents a persisting challenge for scientists. Understanding of lubrication may help to suitably explain tribological processes on the way to replacements...
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Correction for ‘Nanoscale insight into the degradation mechanisms of the cartilage articulating surface preceding OA’ by Tooba Shoaib, et al. , Biomater. Sci. , 2020, 8 , 3944–3955, DOI: 10.1039/D0BM00496K.
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Osteoarthritis (OA) is a degenerative joint disease and a leading cause of disability globally. In OA, the articulating surface of cartilage is compromised by fissures and cracks, and sometimes even worn away completely. Due to its avascular nature, articular cartilage has a poor self-healing ability, and therefore, understanding the mechanisms und...
Conference Paper
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The aim of this study was to determine the effect of two in‐vivo–determined gait patterns, one with low and one with high anteroposterior (AP) motion, on total and backside polyethylene insert wear in comparison with the ISO (International Organization for Standardization) standard 14243‐3. In order to differentiate and accurately quantify topside...
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The aim of this study was to determine the effect of two in-vivo-determined gait patterns, one with low and one with high anteroposterior (AP) motion, on total and backside polyethylene insert wear in comparison with the ISO (International Organization for Standardization) standard 14243-3. In order to differentiate and accurately quantify topside...
Article
Aims A retrospective longitudinal study was conducted to compare directly volumetric wear of retrieved polyethylene inserts to predicted volumetric wear modelled from individual gait mechanics of total knee arthroplasty (TKA) patients. Methods In total, 11 retrieved polyethylene tibial inserts were matched with gait analysis testing performed on t...
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Polyethylene wear remains a contributor to long term failure in total knee replacements (TKRs). Advances in materials have improved polyethylene wear rates, therefore further wear reductions require a better understanding of patient specific factors that lead to wear. Variability of gait within patients is considerable and could lead to significant...
Article
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Total Joint Replacement (TJR) devices undergo standardized wear testing in mechanical simulators while submerged in a proteinaceous testing solution to mimic the environmental conditions of artificial joints in the human body. Typically, bovine calf serum is used to provide the required protein content. However, due to lot-to-lot variability, an un...
Article
Joint Replacement (JR) is one of the most successful and cost‐effective surgical procedures of all medical subspecialties. JR has been shown to reliably decrease pain and restore mobility and function in patients with end‐stage arthritis. As the mean age of our general population continues to increase, so will the number of JRs worldwide. This arti...
Article
The aim of this study was to determine the effect of two in vivo‐determined gait patterns, one with low and one with high anteroposterior (AP) motion, on total and backside polyethylene insert wear in comparison with the ISO standard 14243‐3. In order to differentiate and accurately quantify topside and backside wear, a novel technique was employed...
Article
The purpose of this retrieval study was to determine the effect of implant positioning on wear, taking patient‐related factors into account. Therefore, the volumetric material loss of 59 retrieved tibial liners was quantitatively determined using a coordinate measuring‐machine. All retrievals were made of the same polyethylene and design by a singl...
Chapter
Aseptic loosening remains a leading cause of long-term failure of total knee replacement (TKR) that can limit the lifetime of the implant past the second decade. To help accelerate and facilitate advances in TKR design, our goal was to develop a computational framework based on previous work, that could accurately and efficiently predict the effect...
Article
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Millions worldwide suffer from arthritis of the hips, and total hip replacement is a clinically successful treatment for end‐stage arthritis patients. Typical hip implants incorporate a cobalt alloy (Co–Cr–Mo) femoral head fixed on a titanium alloy (Ti‐6Al‐4V) femoral stem via a Morse taper junction. However, fretting and corrosion at this junction...
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In article 1903008, Shanoob Balachandran, Zita Zachariah, and co‐authors reveal the fretting corrosion mechanisms in a cobalt alloy/titanium alloy taper junction present in modular hip implants. Although the cobalt alloy is more wear resistant than the titanium alloy, microploughing phenomena on the titanium alloy surface promote tribocorrosion in...
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Background: There is interest in minimally invasive solutions that reduce osteoarthritic symptoms and restore joint mobility in the early stages of cartilage degeneration. The aim of the present study was to evaluate an alumina-zirconia composite (AZC) as a counterface for articulation against live cartilage explants in comparison to the clinicall...
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Background Currently, it is not feasible to obtain laboratory-based measures of joint motion in large numbers of older adults. We assessed the utility of a portable depth-sensing camera for quantifying hip and knee joint motion of older adults during mobility testing in the community. Methods Participants were 52 older adults enrolled in the Rush...
Conference Paper
Fretting corrosion of taper junctions is long known and of great concern, because of metal ion and particle release and their related adverse local and systemic effects on the human body (1–3). Orthopedic taper junctions are often comprised of CoCr29Mo6/TiAl6V4 pairings. Beside others the imprinting of the TiAlV-machining marks into the CoCrMo-tape...
Article
Background The knee adduction moment (KAM) is a surrogate measure of mediolateral distribution of loads across the knee joint and is correlated with progression and severity of knee osteoarthritis (OA). Existing biomechanical approaches for unloading the arthritic medial knee compartment vary in their effectiveness in reducing KAM. This study emplo...
Article
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Metal ion release from the orthopedic implants is a great concern for the clinicians and patients. Currently, the inductive coupled plasma-mass spectroscopy (ICP-MS) technique is used to detect and estimate the metal ions in the blood or synovial fluid, which is expensive and needs technical assistance. Hence, the aim of the current work is to deve...
Article
Background: The aim of this study was to compare the polyethylene wear rate, particle size, and particle shape of primary semiconstrained, fixed-bearing, bone-sparing total ankle arthroplasty using conventional ultrahigh-molecular-weight polyethylene (CPE) versus highly cross-linked polyethylene (HXLPE) by applying a level walking input using a jo...
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Category Ankle Arthritis Introduction/Purpose The aim of this study was to compare the polyethylene wear rate, particle size, and particle shape of primary semi-constrained, fixed-bearing, bone-sparing total ankle arthroplasty using conventional ultra-high molecular weight polyethylene (CPE) versus highly cross-linked polyethylene (HXLPE) by apply...
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Introduction: Little is known about the loading patterns in unilateral hip osteoarthritis (OA) and their relationship to radiographic severity and pain. We aimed to examine the loading patterns at the hips of those with unilateral symptomatic hip OA and identify associations between radiographic severity and pain with loading alterations. Methods...
Article
Background: The goal of this study is to set up a functional motion analysis test to examine effects of the anterior cruciate ligament in total knee arthroplasty (TKA) patients by comparing knee kinematics, kinetics, and muscle activation patterns during level and downhill walking for patients with posterior cruciate-retaining (PCR) and bicruciate...
Article
Current treatment for end-stage osteoarthritis is total knee replacement. Given that the number of total knee replacement surgeries is expected to approach 3.48 million by 2030, understanding long-term failure is important. One of the preclinical tests for total knee replacements is carried out using mechanical wear testing under generic walking co...
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Introduction: Pre-clinical testing of hemiarthroplasty devices requires that the tribological conditions present in vivo with live cartilage be closely duplicated. A current limitation in the tribological testing of live cartilage involves the use of cell-culture media as lubricant. Study aim: to develop and test a new hyaluronan-phospholipid ba...
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Background: The fretting-corrosion behavior of mixed metal contacts is affected by various mechanical and electrochemical parameters. Crevice conditions at the junction and patient-specific pathologies can affect the pH of the prosthetic environment. The main objective of this study is to understand the effect of pH variation at the stem/head junc...
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It is well established that the total protein concentration and albumin-to-globulin ratio influence the wear of ultra-high molecular polyethylene (UHMWPE, “polyethylene”) in joint prostheses. A factor on wear not yet studied, but of possible clinical relevance, is protein cleavage. Such cleavage is expected in the presence of an inflammatory respon...
Article
Nearly 20% of patients who have undergone total knee arthroplasty (TKA) report persistent poor knee function. This study explores the idea that, despite similar knee joint biomechanics, the neuro-motor synergies may be different between high-functional and low-functional TKA patients. We hypothesized that (1) high-functional TKA recruit a more comp...
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As the number of annual Total Hip Replacement (THR) surgeries continues to increase, the longevity of metal based hip implants is a major concern. Tribochemical reactions cause the Cobalt-Chromium-Molybdenum (CoCrMo) hip implant to release wear debris that interacts with decomposed proteins to form a tribolayer. We conducted an electrochemical inve...
Article
Recent findings suggest that during wear CoCrMo alloys develop a protein-rich protective tribochemical film formed by interaction of released molybdate ion with proteins in the lubricant. The purpose of this study was to determine the effect of adding molybdate ions directly to the medium on the fretting corrosion of a high carbon CoCrMo alloy in c...
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Background Patient-specific gait and surgical variables are known to play an important role in wear of total hip replacements (THR). However a rigorous model, capable of predicting wear rate based on a comprehensive set of subject-specific gait and component-positioning variables, has to our knowledge, not been reported. Questions/purpose(1) Are th...
Article
Background: It is not known if the loads and motions reported for instrumented knees are generalizable to a larger population of total knee arthroplasty (TKA) patients. The purpose of this study is to (1) report axial implant force data for chair and stair activities for a population of cruciate-retaining TKA patients and (2) compare the populatio...
Article
Objective To investigate the responses of refrigerated osteochondral allograft cartilage (OCA) and fresh cartilage (FC), including cell survival and metabolism, to surgical impaction and proinflammatory cytokines. Design Osteochondral plugs (8 mm diameter) were harvested from prolonged-refrigerated (14-28 days) and fresh (≤24 hours postmortem) hum...
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Context: The overhand pitch is one of the fastest known human motions and places enormous forces and torques on the upper extremity. Shoulder and elbow pain and injury are common in high-level pitchers. A large body of research has been conducted to understand the pitching motion. Evidence acquisition: A comprehensive review of the literature wa...
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Background Many i n vitro damage models investigate progression of cartilage degradation after a supraphysiologic, compressive impact at the surface and do not model shear-induced damage processes. Models also neglect the response to uninterrupted tribological stress after damage. It was hypothesized that shear-induced removal of the superficial zo...
Article
Mechano-biochemical wear encompasses the tribological interplay between biological and mechanical mechanisms responsible for cartilage wear and degradation. The aim of this study was to develop and start validating a novel tribological testing system, which better resembles the natural joint environment through incorporating a live cartilage-on-car...
Article
The purpose of this study was to investigate the effects of trauma and subsequent articulation on adult human ankle cartilage subjected to injurious impact. Trauma was initiated through impaction on talar cartilage explants. Articulation and loading were applied in a joint bioreactor over five consecutive days. The early (24 hrs) effects of impacti...
Article
Recently developed techniques have enabled volume loss measurements on surgically retrieved total knee replacements (TKR). However, it is not well understood how volume loss relates to polyethylene surface damage appearance. Sixty-four fixed bearing cruciate retaining components retrieved from revision and postmortem surgeries were analyzed for pen...
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Considering total hip arthroplasty, so-called tribolayers (aka tribomaterial), consist of carbonaceous material from the periprosthetic joint fluid or bovine serum mixed with nanometer size metal and oxide wear particles. Currently, its growth sequence and rate are unknown. Thus, smooth surfaces of low-Carbon (LC-) vs. high-Carbon (HC-)CoCrMo (Coba...
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Background: Recently, there has been increasing concern in the orthopedic community over the use of hip implant modular devices due to an increasing number of reports of early failure, failure that has been attributed to fretting-corrosion at modular interfaces. Much is still unknown about the electrochemical and mechanical degradation mechanisms...
Article
Hip osteoarthritis (OA) has been shown to affect gait patterns of lower extremities. However, until now, no specific identifying gait characteristics for the various disease stages of hip OA have emerged. The present study addresses the following questions: (1) does a vector-based principal component analysis (PCA) discriminate between various dise...
Article
The knee adduction moment (KAM) is an established marker of compartmental load distribution across the tibiofemoral joint. Research suggests a link between the magnitude of the KAM and center of plantar pressure (COP) thus alterations in the two may be related. The objective of this study was to investigate whether the COP predictably shifts when t...
Article
Posttraumatic osteoarthritis (PTOA) is the most common form of osteoarthritis (OA) of the ankle joint. PTOA occurs as a result of several factors, including the poor regenerative capacity of hyaline articular cartilage as well as increased contact stresses following trauma. The purpose of this article is to review the epidemiology, pathogenesis, an...
Article
Purpose: To investigate the potential causes of diminished knee extension after acute anterior cruciate ligament (ACL) injury using both surface electromyography (sEMG) analysis of the quadriceps and hamstrings, and gait analysis to assess muscle action and tone. Methods: Consecutive patients with an acute ACL tear underwent sEMG and gait analys...
Article
Background The longevity of total hip (THR) and knee replacements (TKR) that used historical bearing materials of gamma-in-air sterilized UHMWPE was affected more by osteolysis in THRs than in TKRs, although osteolysis remains a concern in TKRs. Therefore, the study of polyethylene wear is still of interest for the knee, particularly because few st...
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This study aimed to clarify the influence of various speeding strategies (i.e. adjustments of cadence and stride length) on external joint moments. This study investigated the gait of 52 healthy subjects who performed self-selected normal and fast speed walking trials in a motion analysis laboratory. Subjects were classified into three separate gro...