Total Joint Replacement Devices Research Articles

A Contemporary Approach to Non-Invasive 3D Determination of Individual Masticatory Muscle Forces: A Proof of Concept.

Over the past decade, the demand for three-dimensional (3D) patient-specific (PS) modelling and simulations has increased considerably; they are now widely available and generally accepted as part of patient care. However, the patient specificity of current PS designs is often limited to this patient-matched fit and lacks individual mechanical aspects, or parameters, that conform to the specific patient’s needs in terms of biomechanical acceptance. Most biomechanical models of the mandible, e.g., finite element analyses (FEA), often used to design reconstructive implants or total joint replacement devices for the temporomandibular joint (TMJ), make use of a literature-based (mean) simplified muscular model of the masticatory muscles. A muscle’s cross-section seems proportionally related to its maximum contractile force and can be multiplied by an intrinsic strength constant, which previously has been calculated to be a constant of 37 [N/cm2]. Here, we propose a contemporary method to determine the patient-specific intrinsic strength value of the elevator mouth-closing muscles. The hypothesis is that patient-specific individual mandible elevator muscle forces can be approximated in a non-invasive manner. MRI muscle delineation was combined with bite force measurements and 3D-FEA to determine PS intrinsic strength values. The subject-specific intrinsic strength values were 40.6 [N/cm2] and 25.6 [N/cm2] for the 29- and 56-year-old subjects, respectively. Despite using a small cohort in this proof of concept study, we show that there is great variation between our subjects’ individual muscular intrinsic strength. This variation, together with the difference between our individual results and those presented in the literature, emphasises the value of our patient-specific muscle modelling and intrinsic strength determination protocol to ensure accurate biomechanical analyses and simulations. Furthermore, it suggests that average muscular models may only be sufficiently accurate for biomechanical analyses at a macro-scale level. A future larger cohort study will put the patient-specific intrinsic strength values in perspective.

Adhesion of electrosprayed chitosan coatings using silane surface chemistry

Biomedical implant devices for dental/craniofacial and orthopedic applications are a reliable and effective means for repairing/re-storing function of damaged, diseased or missing tissues. Electrospray coating technologies provide an additive manufacturing route to endow implant surfaces with properties to improve their performance by controlled deposition of desired materials, compounds and/or agents in the form of nano- or micro-particles on the surface of implant devices under relatively mild conditions. They provide a means to control the structure of coatings with high precision that allows the functionalization of complex 3D geometries of the implants with a range of desired physical and bioactive properties. Devices such as dental implants, total joint replacement devices, bone plates and screws that cannot be easily coated by other manufacturing methodologies such as solution casting, sputtering, or electrochemical treatments, can be robustly handled by the electrospray technique. This study focuses on assessing the adhesion of electrosprayed chitosan coatings on model titanium surfaces and screws to explore their potential as an implant treatment technology. To maximize the adhesion strength between the chitosan coating and a titanium surface, a tri-ethoxy-silylbutyraldhyde silane-based treatment is applied to chemically bond the coated chitosan to the substrate. Adhesion strength values are reported and compared between electrosprayed and solution cast chitosan coatings. For both methods, the role played by the silanation process is also explored. It is seen that silanation significantly improves the adhesion of the coatings, and electrosprayed, silanated coatings have a strength (5.87 MPa ± 2.03 MPa) that is comparable to solution-cast, silanated coatings (4.85 MPa ± 1.34 MPa) and offer control and flexibility as an additive manufacturing/coating process. We also, coat titanium screws and measure the loss of mass of chitosan coating during simulated surgery of screwing them into a polyurethane bone foam. The average loss of mass of chitosan is 34.3%, with most of it coming from the leading edge of the screw that experiences maximum shear during drilling. The merits and shortcomings of the electrospray for coating chitosan are discussed with possible improvements for future developments.

Adverse Local Tissue Responses to Failed Temporomandibular Joint Implants

The purpose of this study was to determine whether failed alloplastic temporomandibular joint replacement (TMJR) devices can elicit the aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL) reaction seen in some patients with metal-on-metal hip arthroplasties. This study involved analysis of paraffin-embedded sections of peri-implant tissue from failed TMJ implant cases obtained from 3 independent sources. Hematoxylin and eosin staining, conventional and polarized light microscopy, back-scattered electron imaging, and energy-dispersive x-ray analysis were used. Immunohistochemical methods were used to identify T and B lymphocytes and macrophages. The total TMJR device specimens showed primary macrophage and lymphocytic responses similar to responses reported previously for failed total hip implants, including ALVAL. No chronic or acute inflammation was apparent in the failed hemiarthroplasty TMJR cases. In this limited preliminary study, the local tissue responses to the failed TMJR implants showed similar primary macrophage and lymphocyte responses to previously reported failed metal-on-metal and metal-on-polyethylene orthopedic total joint replacement devices. No such local inflammatory responses were seen with the failed TMJR hemiarthroplasty devices.

Characterization of retrieved total ankle replacement liners

Abstract This paper describes the failure analysis of two Total Ankle Replacement (TAR) devices where one device failed mechanically and the other device failed due to excessive wear and loosening. Optical and confocal imaging procedures were used to identify various failure modes. Fourier transform infrared spectroscopy was used to determine the oxidation index and crystallinity of the liners and compared them with values obtained for a shelf-aged liner which is used as a control. Regression equations were developed based on literature data to correlate oxidation index with strength of the material. 3D models of each liner were constructed to understand the damage modes at surface and sub-surface levels. Shear banding and embrittlement were observed for one of the failed liners. Both abrasive and adhesive wear were observed in the liners but they are not the dominant wear mechanisms unlike in other total joint replacement devices. Based on obtained results, the STAR™ (Scandinavian Total Ankle Replacement) device failed under higher shear and compression stresses at the bearing component resulting in fatigue-induced fracture due to higher torsion generated at the ankle joint. The Agility™ (DePuy) device showed lack of proper bony ingrowth resulting in clinical failure.

Examination of failed retrieved temporomandibular joint (TMJ) implants

In the management of end-stage temporomandibular joint disorders (TMD), surgeons must often resort to alloplastic temporomandibular joint (TMJ) total joint replacement (TJR) to increase mandibular function and form, as well as reduce pain. Understanding wear and failure mechanisms of TMJ TJR implants is important to their in vivo longevity. However, compared to orthopedic TJR devices, functional wear of failed TMJ TJR implants has not been examined. Not only do wear and corrosion influence TJR implant in vivo longevity, but so does reactivity of peri-implant tissue to these two events. The aim of this study was to examine and report on the wear of retrieved, failed metal-on-metal (MoM), metal-on-polymer (MoP), and titanium-nitride coated (TiN Coated) TMJ TJR implant components.A total cohort of 31 TMJ TJR devices were studied of which 28 were failed, retrieved TMJ TJRs, 3 were never implanted devices that served as controls. The mean time from implantation to removal was 7.24years (range 3–15), SD 3.01. Optical microscopy, White Light Interferometry (WLI), Scanning Electron Microscopy (SEM), and Raman spectroscopy were utilized to characterize the surfaces of the devices. Data was acquired and evaluated by analyzing alloy microstructure. Substantial surface damage was observed between the articulating areas of the condylar head and the glenoid fossa components. Damage included pitting corrosion, evidence of deposited corrosion products, specific wear patterns, hard phases, surface depressions, and bi-directional scratches. Electrochemical analysis was performed on the MoM Control, retrieved, failed MoM, and TiN Coated devices. Electrochemical tests consisted of open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) tests conducted using the condylar head of the retrieved failed devices. EIS confirmed material properties as well as corrosion kinetics in vivo help to mitigate corrosion as reflected by the Raman spectroscopy results. In summary, this study demonstrated the role of wear and corrosion interactions on the early failure of TMJ TJR devices.Since the materials employed in most orthopedic TJR devices are similar to those used in TMJ TJR implants, studies such as this can provide data that will improve future embodiment paradigms for both. Further studies will include in vitro investigation of corrosion kinetics and the underlying tribocorrosion mechanism of TMJ TJR devices. Statement of SignificanceAn attempt is made in this study, to examine the retrieved TMJ implants and conduct surface and electrochemical analysis; further a translation research approach is employed to compare the observations from the total hip replacement (THR) retrievals. A total cohort of 31 TMJ TJR devices were studied of which 28 were failed, retrieved TMJ TJRs, 3 were never implanted devices that served as controls. Data was acquired and evaluated by analyzing alloy microstructure. Substantial surface damage was observed between the articulating areas of the condylar head and the glenoid fossa components. Electrochemical analysis was performed on the MoM Control, retrieved, failed MoM, and TiN Coated devices. This study demonstrated the role of wear and corrosion interactions on the early failure of TMJ TJR devices. Since the materials employed in most orthopedic TJR devices are similar to those used in TMJ TJR implants, a comparison study was conducted.

Load-Induced Hydrodynamic Lubrication of Porous Films.

We present an exploratory study of the tribological properties and mechanisms of porous polymer surfaces under applied loads in aqueous media. We show how it is possible to change the lubrication regime from boundary lubrication to hydrodynamic lubrication even at relatively low shearing velocities by the addition of vertical pores to a compliant polymer. It is hypothesized that the compressed, pressurized liquid in the pores produces a repulsive hydrodynamic force as it extrudes from the pores. The presence of the fluid between two shearing surfaces results in low coefficients of friction (μ ≈ 0.31). The coefficient of friction is reduced further by using a boundary lubricant. The tribological properties are studied for a range of applied loads and shear velocities to demonstrate the potential applications of such materials in total joint replacement devices.

Twenty-Year Follow-up Study on a Patient-Fitted Temporomandibular Joint Prosthesis: The Techmedica/TMJ Concepts Device

To evaluate subjective and objective outcomes of patients receiving Techmedica (currently TMJ Concepts) patient-fitted temporomandibular joint (TMJ) total joint replacement (TJR) devices after 19 to 24 years of service. This prospective cohort study evaluated 111 patients operated on by 2 surgeons using Techmedica (Camarillo, CA) patient-fitted TMJ TJR devices from November 1989 to July 1993. Patients were evaluated before surgery and at least 19 years after surgery. Subjective evaluations used standard forms and questions with a Likert scale for 1) TMJ pain (0, no pain; 10, worst pain imaginable), 2) jaw function (0, normal function; 10, no movement), 3) diet (0, no restriction; 10, liquid only), and 4) quality of life (QoL; improved, the same, or worse). Objective assessment measured maximum incisal opening (MIO). Comparison analysis of presurgical and longest follow-up data used nonparametric Mann-Whitney and Wilcoxon signed rank tests. Spearman correlations evaluated the number of prior surgeries in relation to objective and subjective variables. Of the 111 patients, 56 (50.5%) could be contacted and had adequate records for inclusion in the study. Median follow-up was 21 years (interquartile range [IQR], 20 to 22 yr). Mean age at surgery was 38.6 years (standard deviation, 10 yr). Median number of previous TMJ surgeries was 3 (IQR, 4). Presurgical and longest follow-up data comparison showed statistically significant improvement (P < .001) for MIO, TMJ pain, jaw function, and diet. At longest follow-up, 48 patients reported improved QoL, 6 patients reported the same QoL, and 2 patients reported worse QoL. Spearman correlations showed that an increased number of previous surgeries resulted in lower levels of improvement for TMJ pain and MIO. At a median of 21 years after surgery, the Techmedica/TMJ Concepts TJR continued to function well. More previous TMJ surgeries indicated a lesser degree of improvement. No devices were removed owing to material wear.

Temporomandibular Joint Replacement Device Research Wear and Corrosion Technology Transfer from Orthopedics

The general requirements for joint replacement devices emphasizes the importance of device material biocompatibility, with no inflammatory or toxic response to wear beyond a tolerable level, the appropriate mechanical properties for the desired application, and lastly economically viable manufacturing and processing methods. Implicit in these requirements is the importance of understanding wear and failure mechanisms of implanted devices. However, compared to orthopedic total joint replacement (TJR) devices, functional wear failure mechanisms for temporomandibular joint (TMJ) TJR implants have not been clearly defined. Our research group has started initial translational investigations involving the analysis of failed retrieved TMJ TJR devices alloy microstructure compared to control, never implanted, TMJ TJR devices utilizing established orthopedic TJR device retrieval tribocorrosion evaluation protocols. This and future studies will guide future material choices and functional design improvements for TMJ TJR devices. Orthopedic TJR implant schemes may also be improved by understanding the degradation mechanism of TMJ TJR implants, as the materials employed in both TJR devices are similar.

Perioperative, Postoperative, and Prophylactic Use of Antibiotics in Alloplastic Total Temporomandibular Joint Replacement Surgery: A Survey and Preliminary Guidelines

In 2009, the American Academy Of Orthopedic Surgeons recommended lifelong prophylaxis after orthopedic total joint replacement (TJR) before these patients undergo dental, aerodigestive, genitourinary (GU), and gastrointestinal (GI) procedures. Because oral and maxillofacial surgeons worldwide are implanting alloplastic total temporomandibular joint replacements (TMJ TJRs), it appeared reasonable to survey these surgeons to obtain data that might shed some light, not only on this issue, but also to obtain some data to begin to develop preliminary guidelines for the peri- and postoperative use of antibiotics for TMJ TJR using these results and the orthopedic data. A total of 35 surgeons worldwide, members of either the TMJ Concepts or Biomet Microfixation online networks were e-mailed a standard questionnaire surveying their perioperative, postoperative, and prophylactic use of antibiotics for their TMJ TJR cases. Of the 35 surgeons, 26 (74.2%) from 8 different countries responded. A total of 2,476 cases (3,368 joints) were retrospectively surveyed. Of the responding surgeons, 96.2% used, in order of frequency, cefazolin, clindamycin, cephalosporin, or penicillin-based antibiotics in the perioperative period and continued their use for a mean of 7 days (range 5 to 14) postoperatively. Also, 46.2% soaked the TJR components either in the perioperative antibiotic or in vancomycin, poviodine, gentamycin, or peroxide before implantation. In addition, 61.5% irrigated the wounds after device implantation with bacitracin, vancomycin, poviodine, peroxide, or the perioperative antibiotic. These surgeons reported that 51 joints (1.51%) had become infected within a mean of 6 months (range 2 weeks to 12 years) postoperatively. A total of 32 devices (0.95%) required removal and/or replacement. In cases in which the organisms were isolated, the organisms commonly associated with biofilm infection of TJR devices, Staphylococcus aureus, S epidermidis, Peptostreptococcus, and Pseudamonas aeruginosa, were cultured. In only 1 joint (0.003%) was there a suggestion of an association with an invasive dental/aerodigestive, GU/GI procedure. Regarding prophylaxis after TMJ TJRs and before dental/aerodigestive, GU, or GI procedures, 53.8% of the respondents reported that they provided prophylaxis. Of these, 1 recommended doing this for 6 months and 4 for 2 years, such as has been the American Dental Association/American Academy of Orthopedic Surgeons recommendation since 2003; and 9 reported they believe these TMJ TJR patients should have lifetime antibiotic prophylaxis before invasive dental/aerodigestive, GU, or GI procedures. The evidence provided from the present small study survey and a review of the orthopedic data could provide the opportunity to develop guidelines for the preoperative, intraoperative, and postoperative antibiotic management for TMJ TJRs and spur additional research into this important area of patient management.

Improved wear resistance of orthopaedic UHMWPE by reinforcement with zirconium particles

A considerable number of total-joint replacement devices used in orthopaedic medicine involve articulation between a metallic alloy and ultra-high molecular weight polyethylene (UHMWPE). Though this polymer has excellent wear resistance, the wear particulate that is produced leads to the limited lifetime of the devices—osteolytic bone loss. Crosslinking has been shown to reduce the wear rate of UHMWPE, but can cause a reduction in various mechanical properties such as impact toughness. Previous work by the authors has shown that UHMWPE-based composites have wear resistance comparable to the irradiation-crosslinked polymer. However, the selection of the reinforcing material is complicated both by understanding the mechanical behavior of the filler and also by biocompatibility considerations. Zirconium has been shown to have excellent corrosion resistance and biocompatibility, and the authors have used the material as a reinforcing filler in UHMWPE with promising results. Compression-molded UHMWPE composites with up to 20 wt.% of microsized zirconium particles were investigated with regards to wear behavior and impact toughness. These composites showed a significant reduction in wear compared to unfilled polymer while still maintaining impact toughness. These results reinforce the paradigm of using polymer composites for orthopaedic applications and may provide a viable alternative to the property tradeoffs encountered with irradiation crosslinking.

Immunogenecity of Modified Alkane Polymers Is Mediated through TLR1/2 Activation

BackgroundWith the advancement of biomedical technology, artificial materials have been developed to replace diseased, damaged or nonfunctional body parts. Among such materials, ultra high molecular weight alkane or modified alkyl polymers have been extensively used in heart valves, stents, pacemakers, ear implants, as well as total joint replacement devices. Although much research has been undertaken to design the most non-reactive biologically inert polyethylene derivatives, strong inflammatory responses followed by rejection and failure of the implant have been noted.Methodology/Principal FindingsPurification of the alkane polymers from the site of inflammation revealed extensive “in vivo” oxidation as detected by fourier transformed infra-red spectroscopy. Herein, we report the novel observation that oxidized alkane polymers induced activation of TLR1/2 pathway as determined by ligand dependent changes in intrinsic tyrosine fluorescence intensity and NF-κΒ luciferase gene assays. Oxidized polymers were very effective in activating dendritic cells and inducing secretion of pro-inflammatory cytokines. Molecular docking of the oxidized alkanes designated ligand specificity and polymeric conformations fitting into the TLR1/2 binding grooves.Conclusion/SignificanceThis is the first report of a synthetic polymer activating immune responses through TLR binding.

Investigation of articular cartilage and counterface compliance in multi-directional sliding as in orthopedic implants

As the use of total-joint replacement devices has become widespread, debris-induced osteolysis from ultra-high molecular weight polyethylene (UHMWPE) is still the primary challenge to lengthening the pain-free lifetime of these implants. Investigators have long suspected that the natural cartilage-on-cartilage interface found in synnovial joints is an optimal system, but technology has not advanced to the point of producing such an implant for use in total-joint replacement. The authors have investigated the performance of such a joint by developing an in vitro model of a cartilage-on-cartilage system. Bovine articular cartilage was fabricated into pins and subjected to multi-directional sliding in the Dual Axis Wear Simulator (DAWS), a machine developed by the authors to simulate conditions in an in vivo joint. The pins were worn against a rigid stainless steel counterface, similar to that found in conventional total-joint implants, and these results were compared to wear against a compliant polymeric counterface. The rigid counterface produced cartilage wear amounts with a mean of 25.65 mg after 100,000 cycles of 39 N loading and a 6.4-mm square wear path. However, use of the compliant counterface yielded a mean wear value of 9.97 mg for the same testing conditions. It is likely that the mechanism responsible for this wear involves the generation and subsequent depletion of a fluid layer at the interface between the cartilage pin and the counterface such that the majority of material removal occurred during the fluid deficient portions of the wear cycle. This difference in wear amounts was attributed to the substantial difference in contact pressures between the rigid and compliant counterfaces. To estimate the contact pressures in each case, the storage and loss moduli were measured for cartilage samples through dynamic mechanical analysis (DMA). It was found that over a frequency range from 0.1 to 10 Hz, the storage modulus ranged from 470 to 1010 kPa, while the loss modulus increased more modestly, from 176 to 249 kPa. The results of wear testing and the measurement of the viscoelastic properties of articular cartilage suggest the possibility of successful cartilage-on-metal implant systems where the contact pressures are kept low through joint geometry or the use of a biocompatible compliant surface on the metallic component.

Systemic metal-protein binding associated with total joint replacement arthroplasty.

The distribution of titanium [Ti] and chromium [Cr] in serum protein fractions of patients with and without total joint replacements containing Cr and Ti was studied. Three groups were evaluated: 10 patients with cobalt-chromium [CoCr] alloy prostheses and known elevated levels of Cr; 10 patients with Ti containing implants and known elevated levels of Ti; and 10 age matched controls without prostheses. Metal-protein binding was also examined by adding various concentrations of Cr(+3) (CrCl(3)) to control serum. Cr and Ti were bound to serum proteins within specific molecular weight ranges in both patient groups. Two molecular weight ranges were found to bind Cr (at approximately 70 and approximately 180 kDa) in patients with CoCr alloy prostheses, whereas a single molecular weight range (at approximately 70 kDa) was found to bind Ti in patients with Ti alloy implants. This metal-protein binding was reproduced in vitro by adding CrCl(3) at concentrations of approximately 100 and 1000 ppb Cr, which is orders of magnitude higher than that contained in the serum of patients with CoCr alloy implants ( approximately 3 ppb Cr). This suggests that protein binding is initiated in the periprosthetic space where metal concentrations are typically 2-3 orders of magnitude higher than that observed systemically in the serum. In vitro, high molecular weight proteins including immunoglobulins demonstrated the highest affinity to Cr. Determination of specific protein carriers of metal degradation products is an essential component in the assessment of the long-term biological affects of total joint replacement devices.

Systemic metal–protein binding associated with total joint replacement arthroplasty

The distribution of titanium [Ti] and chromium [Cr] in serum protein fractions of patients with and without total joint replacements containing Cr and Ti was studied. Three groups were evaluated: 10 patients with cobalt-chromium [CoCr] alloy prostheses and known elevated levels of Cr; 10 patients with Ti containing implants and known elevated levels of Ti; and 10 age matched controls without prostheses. Metal–protein binding was also examined by adding various concentrations of Cr+3 (CrCl3) to control serum. Cr and Ti were bound to serum proteins within specific molecular weight ranges in both patient groups. Two molecular weight ranges were found to bind Cr (at ≈70 and ≈180 kDa) in patients with CoCr alloy prostheses, whereas a single molecular weight range (at ≈70 kDa) was found to bind Ti in patients with Ti alloy implants. This metal–protein binding was reproduced in vitro by adding CrCl3 at concentrations of ≈100 and 1000 ppb Cr, which is orders of magnitude higher than that contained in the serum of patients with CoCr alloy implants (≈3 ppb Cr). This suggests that protein binding is initiated in the periprosthetic space where metal concentrations are typically 2–3 orders of magnitude higher than that observed systemically in the serum. In vitro, high molecular weight proteins including immunoglobulins demonstrated the highest affinity to Cr. Determination of specific protein carriers of metal degradation products is an essential component in the assessment of the long-term biological affects of total joint replacement devices. © 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 49, 353–361, 2000.

Simultaneous Determination of Aluminium, Titanium and Vanadium in Serum by Electrothermal Vaporization–Inductively Coupled Plasma Mass Spectrometry

L. YU, S. ROY KOIRTYOHANN, MELVIN L. RUEPPEL, ANASTASIA K. SKIPOR and JOSHUA J. JACOBS, J. Anal. At. Spectrom., 1997, 12, 69 DOI: 10.1039/A604797A