bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of flange compliance and mechanical loading on the tissue response to percutaneous devices
Authors: Tramaglini Dawn , Powers Dennis L. , Black Jonathan 
Published: May 2005

AbstractThe failure of most percutaneous devices (PD) is caused by infection initiated by a lack of a tight seal at the skin–device interface. This interface can be disrupted by both extrinsic and intrinsic forces. Many stress reduction methods have been proposed, the most common being the application of a subcutaneous flange. It is widely believed that the bending compliance of the flange plays a significant role in the success or failure of a PD.A study was conducted to observe the effect of flange compliance on local host response in both a functional and nonfunctional setting. Two PDs having flanges with different bending rigidities were implanted percutaneously in goats (n = 8). After a healing period of 2 weeks, half of these devices were externally stimulated with a random load. All the implants were retrieved after 4 weeks and evaluated histologically.The tissue capsule was significantly thicker and the incidence of severe fibrosis and/or necrosis was higher at the flange rim of the functional implants, irrespective of flange compliance. The more compliant devices were encapsulated with a thick fibrous capsule more frequently than the less compliant ones, irrespective of functional status. The more compliant devices also had a greater incidence of foreign body giant cells in the corner region and elicited severe acute inflammation at the corner and top of the flange more frequently than the less compliant implants. Numerous areas of degenerating foreign body giant cells accompanied with fibroblastic proliferation and dystrophic mineralization were identified in many of the capsules beneath the flanges.It was concluded that the rigid implants elicited a more desirable tissue response than the compliant implants while the functional implants elicited a less desirable response than the nonfunctional ones. There was no synergistic or antagonistic relationship between the functional status of the device and flange compliance. © 1993 John Wiley & Sons, Inc.
Histological and histomorphometrical evaluation of the bone reaction to three different titanium alloy and hydroxyapatite coated implants
Authors: Jansen J. A. , van der Waerden J. P. C. M. , Wolke J. G. C. 
Published: May 2005

AbstractThe aim of this study was to investigate the bone response to three different types of titanium (Ti) alloys and hydroxyapatite (HA) coated titanium alloy by histological and histomorphometrical analysis. Therefore, implants made of these materials were inserted into the tibia of rabbits. Implantation times were 6 and 16 weeks. The histological evaluation included measurement of the amount of bone apposition and analysis of the bone reaction and interface characteristics around the implants. The results demonstrated no marked differences in bony reaction to the different implant materials. In addition, the HA coatings showed loss of thickness. © 1993 John Wiley & Sons, Inc.
Effects of ions in aqueous media on hydroxyapatite induction by silica gel and its relevance to bioactivity of bioactive glasses and glass‐ceramics
Authors: Li P. , Ohtsuki C. , Kokubo T. , Nakanishi K. , Soga N. , Nakamura T. , Yamamuro T. 
Published: May 2005

AbstractHydroxyapatite induction by a synthesized pure silica hydrogel was examined in various simulated body fluids (SBFs) having different magnesium, calcium, and phosphate ion concentrations as well as pH values. The silica hydrogel generated biologically active apatite on its surface by taking up calcium and phosphorous ionic groups from a surrounding SBF that was prepared to emulate the human plasma in inorganic composition. The induction period for apatite nucleation on the surface of the silica was largely decreased with the addition of a small amount of the calcium or phosphate ions to the SBF and with an increase in pH, but increased with the addition of magnesium ion. Bioactivity of bioactive materials like Bioglass® and glass‐ceramic A‐W was well interpreted in terms of the rate of apatite formation reflected in these results. Moreover, the results provide the basic knowledge for designing new bioactive materials. © 1993 John Wiley & Sons, Inc.
Corneal endothelium cell adhesion on intraocular lenses in vitro
Authors: Arciola Carla Renata , Cenni Elisabetta , Tarabusi Cristina , Caramazza Roberto , Pizzoferrato Arturo 
Published: May 2005

AbstractAn in vitro evaluation was conducted of the adhesion capabilities of rabbit corneal endothelial cells on intraocular lenses (IOLs) made of heparin‐coated polymethylmethacrylate (HSM‐PMMA). The concave endothelial surfaces of albino rabbit corneas were placed in contact in vitro with the convex surfaces of the optical side of HSM‐PMMA IOLs in 4‐day cultures. PMMA IOLs served as controls. After an incubation period, the preparations were examined via phase‐contrast microscopy and via inverted microscopy after staining with vital dye (neutral red), both with and without the cornea in place. After fixation and staining with Giemsa, the cells adherent on the lens were counted on five different microscopic fields. It was observed that the corneal endothelial cells adhered equally to heparin‐coated and untreated PMMA IOLs. © 1993 John Wiley & Sons, Inc.
A new bioactive glass–ceramic as a coating material on titanium alloy
Authors: Takatsuka Kazutaka , Yamamuro Takao , Kitsugi Toshiaki , Nakamura Takashi , Shibuya Tekehiro , Goto Tatsuya 
Published: May 2005

AbstractApatite–wollastonite‐containing glass–ceramic (A ‐ W · GC) has a strong ability to bond to bone and relatively high mechanical strength. Therefore, as a bulk material it has recently been applied clinically even in load‐bearing sites. In this study, we modified A–W · GC by altering its composition ratio with the removal of CaF2 and the addition of B2O3, and examined the potential use of the resulting new glass–ceramic as a material for coating on a titanium (Ti) alloy. The bioactivity of this new coating (NC) material and its bonding ability to bone were investigated mechanically and histologically. After implantation of the Ti alloy plate coated with this material into the tibiae of rabbits for 2, 3, 4, 8, and 25 weeks, a detaching test was performed. The detaching failure load of the NC plates was compared with those of A–W · GC plates, hydroxyapatite (HA) plates, and uncoated Ti alloy plates implanted in the same way. The failure load of NC was as high as that of A–W · GC for all periods, whereas it was significantly higher at 3 and 4 weeks than that of HA. Uncoated Ti alloy showed lower failure loads for all periods, differing significantly from the other materials. There was no breakage or detachment of the coating layer observed after the detaching test. Histological examinations by CMR, Giemsa surface staining, and SEM‐EPMA showed that NC bonded directly to bone without any intervening soft tissue layer. A calcium–phosphorus‐rich layer (apatite layer) was observed within the coating layer, as is the case in A–W · GC. These results indicate that this new glass–ceramic has earlier bone‐bonding ability and high mechanical strength, making it a promising coating material. © 1993 John Wiley & Sons, Inc.
Metallic wear debris in metal‐backed patellar failure
Authors: Stulberg Bernard N. , Merritt Katharine , Bauer Thomas W. 
Published: May 2005

AbstractEight patients with failure of metal‐backed patellar components were studied for evidence of intraarticular and systemic metal deposition. Seven of the eight patients had failure of a titanium‐based patellar component that then articulated with a cobaltchromium femoral component. One patient had articulation of a cobalt‐chromium patellar component against a cobalt‐chromium femoral component. All components failed by the same pattern of failure. Wearing of the ultra high molecular weight polyethylene was followed by displacement of the polyethylene and then metal‐to‐metal contact of the components.Methods for analysis of the debris included light and electron microscopy of synovial tissue and electron dispersive x‐ray analysis (EDAX) of tissue. Graphite furnace atomic absorption spectroscopy (GFAAS) was done on synovial fluid and synovial tissue as well as urine and blood specimens taken at various times from implantation to patellar revision.Massive deposition of metallic debris within the knee joint was documented both histologically and by GFAAS. Titanium levels reached as high as 2776 ppm (mg/L) in the synovial fluid and as high as 917 mg/g of synovial tissue. Elevation of all the pertinent metals was seen in the tissue and body fluids. Titanium and aluminum levels were the highest. Titanium levels in the serum generally were highest near the time of implant failure. Other metal elevations were variable and could not be related to the time of failure. Synovial fluid levels of all metals and serum levels of titanium are reflective of intraarticular generation of metallic debris.This study demonstrates that in situations of failure of a device, massive intraarticular debris generation occurs and systemic transport will occur. To date no systemic consequences can be attributed to the deposition of debris and follow‐up urine and blood specimens suggest that debridement and revision of the failed device results in lowering of the ion levels. © 1994 John Wiley & Sons, Inc.
Chemical and mechanical degradation of UHMWPE: Report of the development of an in vitro test
Authors: Rimnac Clare M. , Burstein Albert H. , Carr James M. , Klein Robert W. , Wright Timothy M. , Betts Foster 
Published: May 2005

AbstractUltra high molecular weight polyethylene (UHMWPE), used in total joint replacement implants, undergoes oxidative degradation due to gamma radiation sterilization and to exposure to oxidizing agents in the body environment. UHMWPE components also experience large stresses both on and near the articulating surface. It is hypothesized that there is a causal relationship between chemical degradation and mechanical loading of UHMWPE joint components. This report describes the development of an in vitro test to examine the combined effects of chemical environment and cyclic loading history on the chemical, physical, and mechanical properties of UHMWPE. The test apparatus consists of modular load trains, in which strings of UHMWPE test specimens can be subjected to cyclic tensile and compression load ranges, while being exposed to either control or degrading environments. Following cyclic loading for specified time intervals, the specimens can be statically loaded to determine the effect of cyclic loading and environment on the monotonic tensile and compressive stress–strain behavior of UHMWPE. To determine the appropriate control and degrading environments, gamma radiation sterilized UHMWPE specimens were maintained (unloaded) for up to 6 months in aqueous environments of distilled water and three concentrations of hydrogen peroxide (0.01, 0.1, and 1.0%) in distilled water at 37°C. Specimens were evaluated with depth from the surface for changes in density. Infrared spectroscopy (IR) analysis was conducted on selected surface sections. No significant changes in density or surface IR spectra occurred for specimens in distilled water as compared with the UHMWPE in the initial radiation sterilized condition. Specimens exposed to hydrogen peroxide solutions demonstrated changes in density and IR spectra consistent with oxidative degradation and comparable to the changes previously observed on retrieved UHMWPE components. Based on these results, distilled water was selected for the control environment. A 0.5% hydrogen peroxide solution was selected for the test environment, to produce moderate changes at a rate compatible with the maximum 12‐month time period of the experiment. © 1994 John Wiley & Sons, Inc.
Incidence of infection and analysis of contributing factors in revision joint arthroplasty over a two‐year period
Authors: Merritt K. , Panigutti M. A. , Kraay M. J. , Brown S. A. 
Published: May 2005

AbstractThis study examined the incidence of infection and the contributing factors in 166 patients undergoing total joint revision surgery. Of these 32 (19%) had organisms grown from material taken at the local site at the time of revision surgery. Six of the culture‐negative patients were clinically suspected of having an infection. With the inclusion of these six, the total incidence of infection in these revision patients was 23%. This is not the incidence of infection in total joint surgery. This is the incidence of infection in patients undergoing revision surgery for whatever reason. The cause of infection in 53% of the cases was either Staphylococcus aureus or coagulase‐negative Staphylococci. The Gram‐negative bacteria were implicated in only five (15%) of the cases. Many of these infections (31%) were in patients who had had the implant for greater than 7 years. Only 15% of the infections were in patients who had the implant for less than 6 months with an additional 9% being revised in the first year. There were no clinical symptoms or underlying conditions, including allergy, that distinguished the infected from the noninfected group. The infection rate was somewhat higher with the cobalt chromium alloys, somewhat less in the uncemented devices, and somewhat higher in the patients with total knee replacements than those with total hip replacements. The histopathologic analysis revealed that the presence of polymorphonuclear leukocytes (PMNS) was correlated with infection, but most patients with infection had lymphocytes rather than PMNS indicative of a chronic infection. Thus the diagnosis of infection on the basis of histopathology needs to be carefully evaluated. The presence of PMNS is diagnostic for infection, but has a high number of false negatives. The histopathologic data and the data on implantation time indicate that most of these infections are chronic infections. © 1994 John Wiley & Sons, Inc.
Polyethylene wear debris and tissue reactions in knee as compared to hip replacement prostheses
Authors: Schmalzried Thomas P. , Jasty Murali , Rosenberg Andrew , Harris William H. 
Published: May 2005

AbstractDifferences in bearing surface conformity and wear mechanisms suggest that the polyethylene (PE) wear debris generated by total knee replacement (TKR) prostheses should be different than that in total hip replacement prostheses (THR). To address this issue, PE wear debris and the cellular response in periprosthetic tissues from 19 failed TKRs was compared to that from 24 failed THRs using polarized light microscopy and a semiquantitative grading system. The foreign‐body inflammatory reaction in the THR cases was characterized by plump macrophages with a diffuse cytoplasmic birefringence when examined under polarized light, indicating the presence of multiple submicron particles of PE. The majority of the PE particles were <1 μm in size and only a small fraction of the total were >10 μm. The foreign‐body inflammatory reaction in the TKR cases was characterized by giant cells with fewer macrophages. In the TKR specimens, the size range of PE particles was broader than in the hips. PE particles between 2 and 20 μm were frequent in TKR specimens; particles <1 μm in length were less common than in the THR specimens. Diffuse cytoplasmic birefringence was not a characteristic of the TKR cases. These histologic differences were so consistently distinct that the source of the specimen (i.e., from a THR or TKR) could be blindly determined by light microscopy. The size distribution of the PE wear particles in these cases indicate that THRs generate a higher number of submicron PE particles and relatively few large particles while TKRs generate a broader range of particles that includes fewer submicron particles. The observed differences in the cellular responses is likely a direct result of the differences in the spectrum of PE wear particles. These differences may in part account for differences in periprosthetic bone resorption and loosening in TKRs as compared to THRs. © 1994 John Wiley & Sons, Inc.
A new technique for quantitation of metal particulates and metal reaction products in tissues near implants
Authors: Blumenthal N. C. , Cosma V. , Jaffe W. , Stuchin S. 
Published: May 2005

AbstractTissue specimens retrieved from four regions adjacent to hip implants during revision surgery were subjected to a novel treatment to make possible the quantitative separation of residual metal particulates and metal reaction products (metal ions and metal‐protein complexes). The tissues were exposed to sodium hypochlorite solution that degraded and solubilized them, liberating metal reaction products and leaving behind metal wear particles, which were separated by centrifugation. Atomic absorption spectrophotometry was used to analyze the concentrations of the separated metal ions and wear particles. Co ion concentrations were 0.05 to 0.9 mM, Cr ion concentrations were 0.04 to 2.1 mM, and Ti ion concentrations were 0.30 to 0.60 mM. The weight of Co metal particles was 0.1 to 4.9 mg/100 mg tissue, of Cr metal particles 0.07 to 2.2 mg/100 mg tissue, and of Ti particles 0.09 to 5.2 mg/100 mg tissue; one black tissue sample contained 3333 mg Ti/100 mg tissue. No correlation was found between the concentrations of these two entities in the samples examined, probably due to the complex and varied processes creating them. The procedures discussed here will result in data that can help elucidate the separate contributions of metal reaction products and metal particulates to implant loosening. © 1994 John Wiley & Sons, Inc.
Chemical stress relaxation of polyglycolic acid suture
Authors: Hayes Michael J. , Lauren Mark D. 
Published: May 2005

AbstractChemical stress relaxation methods are employed to study chemical and mechanical factors influencing the degradation of uncoated polyglycolic acid (PG) sutures. Specially constructed instrumentation is used to study the kinetics of the load bearing capability of PG (DexonTM) 3‐0 sutures in hydrolytic solution. The effects of pH, temperature, strain rate, and initial load on the rate of chemical stress relaxation are presented. Data show how mechanical factors such as the rate of loading (related to the speed of knot tying), as well as the final tension, are related to the rate of structural degradation. Maximum stability is observed at approximately 40°C, with slower degradation both above and below this point. Results show that the slower and tighter the suture is pulled, the greater its ability to sustain tensile loads during hydrolysis. © 1994 John Wiley & Sons, Inc.
New advances in electronic devices for hole detection
Authors: Cox Mary Jude , Bromberg William J. , Zura Robert D. , Foresman Pamela A. , Morgan Raymond G. , Edlich Richard F. 
Published: May 2005

AbstractHoles in surgical gloves are considered to be an important source of transmission of pathogens between surgeon and patient. Two new glove hole detectors have been devised to alert the surgeon to the presence of holes. These devices have been evaluated using six powder‐free and seven powdered varieties of surgical gloves that were either dry or exposed to hydration. Eight of the 13 surgical gloves hydrated rapidly with water, altering their resistance to the conduction of electricity. Because the Barrier Integrity MonitorTM only has a hydration monitor, 68 false positives occurred during the evaluation, indicating to the surgeon that he/she should change gloves unnecessarily because the glove had no hole. In contrast, the Surgic Alert MonitorTM (SAMTM) had a hydration alarm as well as a glove hole detection alarm. During the 104 tests, the SAMTM device showed no false positives. In the testing of five of the rapidly hydrating types of surgical gloves, the SAMTM device could not reliably detect holes. On the basis of this study, the SAMTM device, in conjunction with gloves that resist hydration, appeared to be a reliable hole detection monitor. © 1994 John Wiley & Sons, Inc.
Ciprofloxacin attachment to porous‐coated titanium surfaces
Authors: Dunn D. S. , Raghavan Srini , Volz R. G. 
Published: May 2005

AbstractA simple and effective method for attaching ciprofloxacin HCl salt to the surface of porouscoated titanium based orthopedic materials was developed. The method utilizes the electrophoretic migration of both fine ciprofloxacin HCl particles and ciprofloxacin ions to deposit the antibiotic salt on a positively biased surface. The quantity of antibiotic deposited can be easily and effectively controlled by varying the time of deposition and applied voltage. In vitro tests have indicated that the antimicrobial activity of the treated surfaces is retained for a period of 5 days. The method allows a significant amount of antibiotic to be deposited and could theoretically be used to deliver antibiotics to the tissues surrounding prosthetic devices in order to prevent postoperative infections. © 1994 John Wiley & Sons, Inc.
Compressive stress relaxation behavior of irradiated ultra‐high molecular weight polyethylene at 37°C
Authors: Waldman Stephen D. , Bryant J. Timothy 
Published: May 2005

AbstractThe preconditioned stress relaxation behavior of irradiated ultra‐high molecular weight polyethylene (UHMWPE), a commonly used bearing surface in total joint replacements (TJR), was modelled in uniaxial compression at 37°C. Twenty cylindrical specimens (10 mm dia. × 27 mm length) were machined from a compression molded plate of medical grade UHMWPE and γ‐irradiated to a minimum dose of 2.5 Mrad. At an initial strain rate 1000%/s, five specimens were each tested at constant strains of 1, 2, 5 and 10%. The modified superposition principle provided a good agreement of the nonlinear viscoelastic (stress relaxation) behavior of UHMWPE (standard error of 0.0753 MPa). © 1994 John Wiley & Sons, Inc.
Effects of fixation technique on displacement incompatibilities at the bone–implant interface in cementless total knee replacement in a canine model
Authors: Berzins Aivars , Sumner Dale R. , Turner Thomas M. , Natarajan Raghu 
Published: May 2005

AbstractBone–implant displacements can be caused by rigid body motion and by differences in material properties of the implant and bone. In the present study of the tibial component in total knee replacement, we tested a series of tibial component fixation designs to determine how certain design features influenced the magnitude of the tangential displacement between the component and supporting bone in a canine model. The transverse expansion of the proximal tibia under static axial loading was measured in the intact tibia and then in the same bone following implantation of tibial components with different interface characteristics: cementless flat smooth, cementless flat porous‐coated, cementless flat porous‐coated with screws, cementless pegged porous‐coated, cementless pegged porous‐coated with screws, cemented pegged, and cemented pegged with screws. In all cases, the magnitude of the transverse expansion increased with higher applied loads. When the statistical analysis was restricted to the cementless interfaces, the presence/absence of the porous coating, the presence/absence of pegs, and the use of screws had no significant influence on tibial expansion. However, in an analysis including the cemented and cementless pegged components, tibial expansion was reduced with the use of screws. The magnitude of the interface motion due to these displacement incompatibilities was approximately fivefold lower than the amount of interface motion related to rigid body motion found in a separate study with the canine model. The measured expansion was similar in the intact tibiae and the implanted tibiae, suggesting that the transverse constraint in the canine proximal tibia must be provided by the surrounding cortical ring rather than the subchondral bone. © 1994 John Wiley & Sons, Inc.