Modular Exchange Research Articles

Total hip arthroplasty instability in Italy.

Hip dislocation is a major and common complication of total hip arthroplasty (THA), which appears with an incidence between 0.3% and 10% in primary total hip arthroplasties and up to 28% in revision THA. The hip dislocations can be classified into three groups: early, intermediate and late. Approximately two-thirds of cases can be treated successfully with a non-operative approach. The rest require further surgical intervention. The prerequisite to developing an appropriate treatment strategy is a thorough evaluation to identify the causes of the dislocation. In addition, many factors that contribute to THA dislocation are related to the surgical technique, mainly including component orientation, femoral head diameter, restoration of femoral offset and leg length, cam impingement and condition of the soft tissues. The diagnosis of a dislocated hip is relatively easy because the clinical situation is very typical. Having identified a dislocated hip, the first step is to perform a closed reduction of the implant. After reduction you must perform a computed tomography scan to evaluate the surgical options for treatment of recurrent dislocation that include: revision arthroplasty, modular components exchange, dual-mobility cups, large femoral heads, constrained cups, elimination of impingement and soft tissue procedures. The objective is to avoid further dislocation, a devastating event which is increasing the number of operations on the hip. To obtain this goal is useful to follow an algorithm of treatment, but the best treatment remains prevention.

Success of Debridement and Implant Retention in Periprosthetic Joint Infection – Does the Surgeon Matter?

Objective:Prosthetic joint infection (PJI) is a devastating complication following total joint arthroplasty (TJA). In acute haematogenous and early post-operative PJI, debridement and implant retention (DAIR) surgery is often the initial treatment and success rates vary. This study aimed to identify factors affecting success rates of DAIR and in particular whether involvement of a lower limb arthroplasty surgeon can affect outcome.Method:This retrospective review included one hundred and sixty-two patients undergoing DAIR for first-episode PJI following hip and knee arthroplasty at one of three tertiary hospitals. Treatment success was defined as no relapse within two years of DAIR. Data on patient, hospital, and surgical factors were identified including duration of symptoms, time from primary, previous revisions, age of prosthesis, bacterial subtype, whether modular component exchange was performed and whether an arthroplasty surgeon performed the procedure. Adjusted multivariate analysis was performed to identify factors associated with success of the DAIR procedure.Results:Overall success rate of DAIR in both hip and knee arthroplasty was 60%. A specialist arthroplasty surgeon was present in 42% of cases. Arthroplasty surgeons performed modular exchange in 51% of cases compared to 32.5% for other surgeons. Inclusion of modular exchange in the procedure was the only factor associated with DAIR success (OR 3.1, p<0.013). Time to theatre of less than 24 hours (OR 0.59), duration of symptoms less than one week (OR 1.28), age of prosthesis less than 3 months (OR 1.47) and having an arthroplasty surgeon perform DAIR (OR 1.6) did not lead to statistically significant improvements in success rate.Conclusions:Modular exchange was associated with a significantly higher success rate for both hip and knee PJI, suggesting thorough debridement is important in DAIR. Arthroplasty surgeons were more likely to perform modular exchange, but their presence in theatre alone did not reduce the risk of failure.

National joint registry data underestimates the burden of prosthetic joint infection

Objective:Joint registries are powerful tools for tracking outcomes following joint arthroplasty. However recent literature has exposed deficiencies in data accuracy when reporting re-operations for prosthetic joint infections (PJI), particularly when no components are changed. The aim of this study was to compare accuracy of data from the New Zealand Joint Registry (NZJR) to a multi-centre audit of hospital records to establish the rate of capture for PJI reoperations.Methods:We followed 4009 patients undergoing total knee or hip arthroplasty performed at the three tertiary referral hospitals from January 2006 to December 2008 for two years. The reoperation rate for PJIs was extracted from the NZJR. In addition, an audit of hospital records for the same patients was carried out to identify reoperations for PJI. The audit data was then compared to the NZJR data.Results:The NZJR reported a reoperation rate of 0.67% for PJI within two years of the primary arthroplasty compared to 1.1% from the audit of hospital records, giving the NZJR a sensitivity of 63%. Only 36% of washout only procedures and 58% of modular exchange procedures were captured. Surgeons were more likely to report PJIs to NZJR if they performed the primary procedure.Conclusion:National joint registry data significantly underestimates the rate of reoperation for PJI. Strategies for improving data accuracy may include revising the registry forms to include reoperation without change of components and frequent validation of national data with other databases.

New Zealand Joint Registry data underestimates the rate of prosthetic joint infection

Background and purpose — Recent studies have revealed deficiencies in the accuracy of data from joint registries when reoperations for prosthetic joint infections (PJIs) are reported, particularly when no components are changed. We compared the accuracy of data from the New Zealand Joint Registry (NZJR) to a multicenter audit of hospital records to establish the rate of capture for PJI reoperations. Methods — 4,009 cases undergoing total knee or hip arthroplasty performed at 3 tertiary referral hospitals over a 3-year period were audited using multiple hospital datasets and the NZJR. The number of reoperations for PJI that were performed within 2 years of the primary arthroplasty was obtained using both methods and the data were compared. Results — The NZJR reported a 2-year reoperation rate for PJI of 0.67%, as compared to 1.1% from the audit of hospital records, giving the NZJR a sensitivity of 63%. Only 4 of 11 debridement-in-situ-only procedures and 7 of 12 modular exchange procedures were captured in the NZJR. Interpretation — The national joint registry underestimated the rate of reoperation for PJI by one third. Strategies for improving the accuracy of data might include revising and clarifying the registry forms to include all reoperations for PJI and frequent validation of the registry data against other databases.

Photoluminescent polysaccharide-coated germanium(IV) oxide nanoparticles

In current biomedically oriented research, the development of a biomimetic nanoparticle platform is of interest to provide a molecular toolbox (i.e., allowing easy modular exchange of its parts depending on actual needs while being nontoxic and allowing real-time recognition and tracking using various methods, such as fluorescence). We report the development of germanium(IV) oxide-polysaccharide composite particles possessing these properties. The nanoparticles are based on a crystalline germanium oxide core with a size range of 20–30 and 300–900 nm. Two new simple coating techniques were compared for the preparation of the photoluminescent polysaccharide-coated germanium(IV) oxide nanoparticles. The germanium(IV)-based core allows for in situ polysaccharide attachment via direct chelation. In addition, the nanoparticles were coated with thin layer of silicon oxide. After coating, 3-(triethoxysilyl)propyl isocyanate was grafted onto the surface, and the polysaccharides were immobilized on the particle surface via a covalent urethane linkage, which allows for an even more stable polysaccharide coating than that obtained via chelation. This approach provides access to a new material platform for biological track and image applications.

High Failure Rate of Modular Exchange With a Specific Design of a Constrained Liner in High-Risk Patients Undergoing Revision Total Hip Arthroplasty

BackgroundAddressing recurrent instability in patients with poor bone stock and inadequate abductor tensioning remains a challenge in revision total hip arthroplasty. One treatment method is implantation of a constrained liner. The purpose of this study was to determine clinical outcomes, redislocation rate, and revisions of a focally constrained liner in a high-risk patient cohort. MethodsFifty-eight hips between 2008 and 2011 underwent implantation of a focally constrained liner. Nineteen were placed concurrent with acetabular component revision and 39 were placed into a well-fixed acetabular shell. Mean age was 69 years and mean number of previous ipsilateral hip surgeries was 4.2. At mean follow-up of 3.5 years, we analyzed clinical outcomes, redislocation, and revisions. ResultsMean Harris Hip Scores was 74. Fourteen hips (24%) were revised and 3 hips (5%) required reoperation at final follow-up. Eleven hips (19%) redislocated at a mean time to dislocation of 12.2 months; 31% (11 of 36 patients) that underwent modular exchange specifically for instability redislocated. Risk factors for redislocation included number of previous surgeries (P = .013), implantation of a 28 mm femoral head (hazards ratio 12.8), revision indication of instability (P = .04), and modular exchange with constrained liner implantation without acetabular shell revision (P = .01). ConclusionImplantation of a focally constrained liner in revision total hip arthroplasty for recurrent instability has a high failure rate, especially with a modular exchange. Although concurrent acetabular revision had a lower redislocation rate, the decision to revise a well-fixed cup should be weighed with potential complications associated with cup revision.

Design and Analysis of Scanning Probe Microscopy Cantilevers With Microthermal Actuation

The scanning probe microscope has revolutionized our ability to image and characterize the physical and chemical properties of material with atomic resolution. It has evolved as a versatile instrument for nanofabrication including atomic deposition, nanolithography, nanomachining, atomic manipulation, and assembly. However, in order to enable practical nanofabrication with scanning probe tips, it is critical to address the issues of throughput, tip wear effects, chemical cross contamination, and scalability. In this paper, we address these issues by designing, optimizing, fabricating, and testing active electromechanical cantilever probes with an integrated microgripper for automated modular tip exchange. The cantilevers are designed and optimized to be compatible with existing atomic force microscope systems. Mechanical performance and optimization are carried out by the development of an analytical electrothermomechanical model and multiphysics finite-element analysis. The silicon cantilevers are formed by microfabrication processes and characterized by scanning electron microscopy, laser vibrometry, and in situ optical microscopy current–voltage studies. The cantilever grippers are shown to actuate with a maximum displacement of $3~\mu \text{m}$ for each arm at an applied voltage of 4 V 6- $\mu \text{m}$ total displacement for grasping modular tool-tips. Gripping is demonstrated by grasping and releasing of a cylindrical microtool (wire). [2014-0332]

Evolution and Emergence of Enteroviruses through Intra- and Inter-species Recombination: Plasticity and Phenotypic Impact of Modular Genetic Exchanges in the 5’ Untranslated Region

Genetic recombination shapes the diversity of RNA viruses, including enteroviruses (EVs), which frequently have mosaic genomes. Pathogenic circulating vaccine-derived poliovirus (cVDPV) genomes consist of mutated vaccine poliovirus (PV) sequences encoding capsid proteins, and sequences encoding nonstructural proteins derived from other species’ C EVs, including certain coxsackieviruses A (CV-A) in particular. Many cVDPV genomes also have an exogenous 5’ untranslated region (5’ UTR). This region is involved in virulence and includes the cloverleaf (CL) and the internal ribosomal entry site, which play major roles in replication and the initiation of translation, respectively. We investigated the plasticity of the PV genome in terms of recombination in the 5’ UTR, by developing an experimental model involving the rescue of a bipartite PV/CV-A cVDPV genome rendered defective by mutations in the CL, following the co-transfection of cells with 5’ UTR RNAs from each of the four human EV species (EV-A to -D). The defective cVDPV was rescued by recombination with 5’ UTR sequences from the four EV species. Homologous and nonhomologous recombinants with large deletions or insertions in three hotspots were isolated, revealing a striking plasticity of the 5’ UTR. By contrast to the recombination of the cVDPV with the 5’ UTR of group II (EV-A and -B), which can decrease viral replication and virulence, recombination with the 5’ UTRs of group I (EV-C and -D) appeared to be evolutionarily neutral or associated with a gain in fitness. This study illustrates how the genomes of positive-strand RNA viruses can evolve into mosaic recombinant genomes through intra- or inter-species modular genetic exchanges, favoring the emergence of new recombinant lineages.

Study of Hydraulic Characteristics of Modular Heat and Mass Exchange Packed Contact Device

Hydraulic resistance of contact device for implementing high-heat mass exchange processes is analyzed. Hydraulic resistance values for several configurations of the device are given, computational correlations are proposed, and distinctive features of resistance curves are noted.

Diagnosis and Management of Adverse Local Tissue Reactions Secondary to Corrosion at the Head-Neck Junction in Patients With Metal on Polyethylene Bearings

We reviewed 27 patients who underwent revision for an adverse local tissue reaction (ALTR) secondary to corrosion at the head-neck junction with MoP bearings. Serum cobalt and chromium levels were elevated in all cases, with a mean cobalt of 11.2ppb and chromium of 2.2ppb. Patients underwent modular bearing exchange, including a ceramic head with a titanium sleeve in 23 of 27 cases with only one recurrence of ALTR in one of the four patients not treated with a ceramic head. The diagnosis of ALTR secondary to corrosion is associated with cobalt levels of >1ppb with cobalt levels elevated above chromium. Retention of a well-fixed stem and modular exchange to a ceramic head leads to resolution of symptoms and decreases in metal levels.

Structure-guided sequence specificity engineering of the modification-dependent restriction endonuclease LpnPI.

The eukaryotic Set and Ring Associated (SRA) domains and structurally similar DNA recognition domains of prokaryotic cytosine modification-dependent restriction endonucleases recognize methylated, hydroxymethylated or glucosylated cytosine in various sequence contexts. Here, we report the apo-structure of the N-terminal SRA-like domain of the cytosine modification-dependent restriction enzyme LpnPI that recognizes modified cytosine in the 5′-C(mC)DG-3′ target sequence (where mC is 5-methylcytosine or 5-hydroxymethylcytosine and D = A/T/G). Structure-guided mutational analysis revealed LpnPI residues involved in base-specific interactions and demonstrated binding site plasticity that allowed limited target sequence degeneracy. Furthermore, modular exchange of the LpnPI specificity loops by structural equivalents of related enzymes AspBHI and SgrTI altered sequence specificity of LpnPI. Taken together, our results pave the way for specificity engineering of the cytosine modification-dependent restriction enzymes.

Розробка модульної системи інформаційного обміну прив’язної підводної системи

Розробка модульної системи інформаційного обміну прив’язної підводної системи

The IRIS Development Platform and Proposed Object-Oriented Data Base

Various code development platforms, such as the ATHENA Framework [1] of the ATLAS [2] experiment encounter lengthy compilation/linking times. To augment this situation, the IRIS Development Platform was built as a software development framework acting as compiler, cross-project linker and data fetcher, which allow hot-swaps in order to compare various versions of software under test. The flexibility fostered by IRIS allowed modular exchange of software libraries among developers, making it a powerful development tool. The IRIS platform used input data ROOT-ntuples [3]; however a new data model is sought, in line with the facilities offered by IRIS. The schematic of a possible new data structuring—as a user implemented object oriented data base, is presented.

Optimized design of substrate-integrated hollow waveguides for mid-infrared gas analyzers

Design and analytical performance studies are presented for optimizing a new generation of hollow waveguides suitable for quantitative gas sensing—the so-called substrate-integrated hollow waveguide (iHWG). Taking advantage of a particularly compact Fourier transform infrared spectrometer optimized iHWG geometries are investigated toward the development of a multi-constituent breath analysis tool compatible for usage, e.g., in exhaled mouse breath analysis. Three different iHWG geometries were compared, i.e., straight, meandering one-turn and meandering two-turn waveguide channels aiming at maximizing the related analytical figures-of-merit including the achievable limits of detection for selected exemplary analytes. In addition, efficient coupling of infrared (IR) radiation into straight iHWGs was investigated using integrated optical funnel structures. Calibration functions of butane in nitrogen serving as IR-transparent matrix gas were established and compared for the various iHWG geometries. Given the tidal volume of exhaled breath (EB) samples ranging from a few hundreds of milliliters (human, swine) to a few hundreds of microliters (mouse), it is essential for any given analysis to select an appropriate waveguide geometry and volume yet maintaining (i) a compact footprint ensuring hand-held instrumentation, (ii) modular exchange of the iHWG according to the analysis requirement yet with constant device format, and (iii) enabling inline/online measurement capabilities toward continuous EB diagnostics.

Intertypic modular exchanges of genomic segments by homologous recombination at universally conserved segments in human adenovirus species D.

Human adenovirus species D (HAdV-D), which is composed of clinically and epidemiologically important pathogens worldwide, contains more taxonomic "types" than any other species of the genus Mastadenovirus, although the mechanisms accounting for the high level of diversity remain to be disclosed. Recent studies of known and new types of HAdV-D have indicated that intertypic recombination between distant types contributes to the increasing diversity of the species. However, such findings raise the question as to how homologous recombination events occur between diversified types since homologous recombination is suppressed as nucleotide sequences diverge. In order to address this question, we investigated the distribution of the recombination boundaries in comparison with the landscape of intergenomic sequence conservation assessed according to the synonymous substitution rate (dS). The results revealed that specific genomic segments are conserved between even the most distantly related genomes; we call these segments "universally conserved segments" (UCSs). These findings suggest that UCSs facilitate homologous recombination, resulting in intergenomic segmental exchanges of UCS-flanking genomic regions as recombination modules. With the aid of such a mechanism, the haploid genomes of HAdV-Ds may have been reshuffled, resulting in chimeric genomes out of diversified repertoires in the HAdV-D population analogous to the MHC region reshuffled via crossing over in vertebrates. In addition, some HAdVs with chimeric genomes may have had the opportunity to avoid host immune responses thereby causing epidemics.

You Can Do Arthroplasty in a Young Patient, But…

You Can Do Arthroplasty in a Young Patient, But…

The episodic evolution of fibritin: traces of ancient global environmental alterations may remain in the genomes of T4‐like phages

The evolutionary adaptation of bacteriophages to their environment is achieved by alterations of their genomes involving a combination of both point mutations and lateral gene transfer. A phylogenetic analysis of a large set of collar fiber protein (fibritin) loci from diverse T4-like phages indicates that nearly all the modular swapping involving the C-terminal domain of this gene occurred in the distant past and has since ceased. In phage T4, this fibritin domain encodes the sequence that mediates both the attachment of the long tail fibers to the virion and also controls, in an environmentally sensitive way, the phage's ability to infect its host bacteria. Subsequent to its distant period of modular exchange, the evolution of fibritin has proceeded primarily by the slow vertical divergence mechanism. We suggest that ancient and sudden changes in the environment forced the T4-like phages to alter fibritin's mode of action or function. The genome's response to such episodes of rapid environmental change could presumably only be achieved quickly enough by employing the modular evolution mechanism. A phylogenetic analysis of the fibritin locus reveals the possible traces of such events within the T4 superfamily's genomes.

Liner Exchange in Total Knee Arthroplasty

Exchange of the tibial liner in revision knee arthroplasty for wear and other indications is controversial. The purpose of the study was to determine the clinical success and reoperation rate for liner exchange performed for four groups of patients. Thirty-nine revisions were identified in which modular liner exchange was performed: polyethylene wear (12 knees), acute infection (11 knees), instability (4 knees), and a variety of other diagnoses (12 knees). The knees were evaluated using the systems of the Knee Society. The mean follow-up time was 4.3 years. Liner exchange for wear was successful in all 12 patients: for acute infection, in 9 of 11 patients; for instability, in 3 of 4 patients; for other diagnoses, in 10 of 12 patients. There were significant improvements in the pain score in all four groups and significant improvement in the function score in the infection and other diagnoses groups. With the use of six criteria, these observations suggest that liner exchange for wear is successful.

Modular exchange of substrate-binding loops alters both substrate and cofactor specificity in a member of the aldo-keto reductase superfamily

Substrate specificity in the aldo-keto reductase (AKR) superfamily is determined by three mobile loops positioned at the top of the canonical (α/β)(8)-barrel structure. These loops have previously been demonstrated to be modular in a well-studied class of AKRs, in that exchanging loops between two similar hydroxysteroid dehydrogenases resulted in a complete alteration of substrate specificity (Ma,H. and Penning,T.M. (1999) Proc. Natl Acad. Sci. USA, 96, 11161-11166). Here, we further examine the modularity of these loops by grafting those from human aldose reductase (hAR) into the hyperthermostable AKR, alcohol dehydrogenase D (AdhD), from Pyrococcus furiosus. Replacement of Loops A and B was sufficient to impart hAR activity into AdhD, and the resulting chimera retained the thermostability of the parent enzyme. However, no active chimeras were observed when the hAR loops were grafted into a previously engineered cofactor specificity mutant of AdhD, which displayed similar kinetics to hAR with the model substrate dl-glyceraldehyde. The non-additivity of these mutations suggests that efficient turnover is more dependent on the relative positioning of the cofactor and substrate in the active site than on binding of the individual species. The ability to impart the substrate specificities of mesostable AKRs into a thermostable scaffold will be useful in a variety of applications including immobilized enzyme systems for bioelectrocatalysis and fine chemical synthesis.

Characterization of Plasmids in a Human Clinical Strain of Lactococcus garvieae

The present work describes the molecular characterization of five circular plasmids found in the human clinical strain Lactococcus garvieae 21881. The plasmids were designated pGL1-pGL5, with molecular sizes of 4,536 bp, 4,572 bp, 12,948 bp, 14,006 bp and 68,798 bp, respectively. Based on detailed sequence analysis, some of these plasmids appear to be mosaics composed of DNA obtained by modular exchange between different species of lactic acid bacteria. Based on sequence data and the derived presence of certain genes and proteins, the plasmid pGL2 appears to replicate via a rolling-circle mechanism, while the other four plasmids appear to belong to the group of lactococcal theta-type replicons. The plasmids pGL1, pGL2 and pGL5 encode putative proteins related with bacteriocin synthesis and bacteriocin secretion and immunity. The plasmid pGL5 harbors genes (txn, orf5 and orf25) encoding proteins that could be considered putative virulence factors. The gene txn encodes a protein with an enzymatic domain corresponding to the family actin-ADP-ribosyltransferases toxins, which are known to play a key role in pathogenesis of a variety of bacterial pathogens. The genes orf5 and orf25 encode two putative surface proteins containing the cell wall-sorting motif LPXTG, with mucin-binding and collagen-binding protein domains, respectively. These proteins could be involved in the adherence of L. garvieae to mucus from the intestine, facilitating further interaction with intestinal epithelial cells and to collagenous tissues such as the collagen-rich heart valves. To our knowledge, this is the first report on the characterization of plasmids in a human clinical strain of this pathogen.