A review of 71 cases of infected total knee arthroplasty: mid-term to long-term follow-up

Departamentul de Chirurgie Ortopedică și Reabilitare, Universitatea Tech din Texas, Centrul de Știinţe ale Sănătaţii, Școala de Medicină Paul L. Foster, El Paso, Texas, Statele Unite ale Americii, Departamentul de Chirurgie Ortopedică, Spitalul General Buffalo, Universitatea de Stat din New York, Buffalo, New York, Statele Unite ale Americii, Departamentul de Chirurgie Ortopedică a Universităţii Harvard, Spitalul General Massachusetts, Boston, Statele Unite ale AmericiiIntroducere. În cadrul acestui studiu au fost evaluate caracteristici și rezultate la termen mediu și lung ale cazurilor de artroplastie totală de genunchi (ATG) și ale infecţiilor asociate cu acestea, care au fost tratate prin diferite metode. Material și metode. Studiul retrospectiv reflectă rezultatele a 71 de cazuri de ATG, infectate și tratate în perioada august 1993 – august 2005. Datele colectate includ înregistrări medicale cu privire la sexe, clasificarea infecţiilor periprotetice (IPP), comorbiditatea pacienţilor, criteriile de diagnostic ale IPP, rezultatele microbiologice și histopatologice, tratamentele chirurgicale și antimicrobiene, modalitaţile de tratament, complicaţiile, consecinţele, precum și rezultatele tratamentului. Nivelul de evidenţă: nivel terapeutic III. Rezultate. Vârsta medie a pacienţilor a constituit 70 de ani (extreme, 43–88 de ani). Mediana duratei de supraveghere – 10,8 ani (extreme, 5 – 20 de ani). Treizeci și trei (46,5%) de pacienţi au prezentat multipli factori de risc pentru IPP. Principalii patogeni izolaţi au fost stafilococii coagulazo-negativi – 26 (37%), Staphylococcus aureus – 16 (22,4%). Metodele de tratament ale ATG infectate au fost: înlocuirea în două etape – 59 (83%) de cazuri, debridare și retenţie – 5 (7,2%) cazuri, artrodeza – 5 (7,2%) cazuri, excizie-artroplastie – 2 (2,8%) cazuri. La sfârșitul perioadei de supraveghere, 17 genunchi (24%) au suportat intervenţie repetată, dintre care 10 (14%) – îndepărtarea componentelor din cauza reinfectării. Doi genunchi s-au reinfectat de 3 ori, trei genunchi – de două ori. Prima reintervenţie după reinfectare a fost efectuată după 1,2 ani (mediana), cu extreme cuprinse între 0,04 și 2,5 ani. Analiza curbelor Kaplan-Meier „de supravieţuire” a constatat că la 5 ani fără reintervenţie au ajuns 90,5% (95% CI între 85,3% și 96,1%) dintre pacienţi, iar la 10 ani – 82% (95% CI între 70,3% și 94,5%). Scorurile Asociaţiei Genunchiului (engl. Knee Society score): scorurile de durere, scorurile funcţionale, amplituda mișcării (engl. range of motion, ROM) – îmbunătăţite. Concluzii. Tratamentul ATG infectate este o sarcină dificilă, cu rezultate nesatisfăcătoare la termen mediu și lung. Aproximativ fiecare al patrulea pacient a necesitat o reintervenţie, iar 14% dintre pacienţi s-au reinfectat în primii 2,5 ani. Jumă- tate dintre pacienţii cu reinfecţie a ATG s-au reinfectat din nou. În majoritatea cazurilor, pacienţii s-au reinfectat cu același microorganism, dar mai virulent. Tratamentul unei ATG infectate ar putea fi ales în funcţie de tipul de infecţie (acută sau cronică), durata ei, stabilitatea implantului, specia agentului patogen, calitatea și integritatea osului și ţesutului moale.Introduction. In the present study, the characteristics and mid-term to long-term outcomes of total knee arthroplasty (TKA) associated infections treated with different types of approaches were evaluated. Material and methods. A retrospective study of the results of 71 infected TKA treated between August 1993 and August 2005. The data included medical records, gender, periprosthetic infection (PPI) classification, patients’ comorbidities, PPI diagnostic criteria, microbiology and histopathology results, surgical and antimicrobial therapy, treatment modality, complications, follow up, and treatment results. Level of Evidence: Therapeutic Level III. Results. Median age was 70 years (range, 43–88). Median follow-up 10.8 years (range, 5–20). Thirty-three patients had multiple risk-factors for PPI. The main pathogens isolated were Coagulase-negative staphylococci 26 (37%), Staphylococcus aureus 16 (22.4%). The treatment methods of TKA infection were two-stage exchange in 59 (83%), debridement and retention – 5 (7.2%), arthrodesis – 5 (7.2%), excision arthroplasty 2 (2.8%). At final follow up, 17 knees (24%) had required reoperation: 10 knees (14%) – component removal for reinfection. Two knees were reinfected 3 times, three knees – two times. The median time to first reoperation for reinfection was 1.2 years (range, 0.04–2.5 years). By Kaplan-Meier survival analysis the estimated survivals free of reoperation for infection were 90.5% (95% confidence intervals, 85.3% to 96.1%) at 5 years and 82% (95% confidence intervals, 70.3% to 94.5%) at 10 years. The Knee Society scores: Pain scores, Functional scores, ROM improved. Conclusions. TKA infections treatment is a difficult task leading to a high rate of unsatisfactory mid-term and longterm results. About one forth of patient require reoperation, 14% become reinfected in first 2.5 years. Half of reinfected patients get reinfected repeatedly. In most cases patients are reinfected with the same microorganism but more virulent. TKA infection treatment option should be chosen according to the type of infection (acute or chronic), the duration of infection, the stability of the implant, the type of microorganism causing infection, bone quality and integrity, and the quality of the soft-tissue

Double reading in breast cancer screening : cohort evaluation in the CO-OPS trial

Purpose: To investigate the effect of double readings by a second radiologist on recall rates, cancer detection and characteristics of cancers detected in the National Health Service Breast Screening Program in England. Materials and Methods: In this retrospective analysis we evaluated 805,206 women through screening and diagnostic test results by extracting one year of routine data from 33 English breast screening centers. Centers used double reading of digital mammograms, with arbitration if there were discrepant reads. Information on reader decisions, with results of follow-up tests, were used to explore the effect of the second reader. The statistical tests used were the test for equality of proportions, the χ2 test for independence and the t-test. Results: The first reader recalled 4·76%, (38295/805206, 95% CI 4·71%-4·80%) of women. Two readers recalled 6·19% in total, (49857/805206, 95% CI 6·14%- 6·24%), but arbitration of discordant reads reduced recall rate to 4·08%, (32863/805206, 95% CI 4·04%-4·12%, p<0.001). 7055 cancers were detected of which 627 (8·89%, 95% CI 8·22%-9·55%, p<0.001) were detected by the second reader only. These additional cancers were more likely to be ductal carcinoma in situ, (30·5% (183/600) vs 22.0% (1344/6114), p<0.001); and additional invasive cancers were smaller (mean 14·2mm vs 16·7mm, p<0.001), had fewer involved nodes, and were likely to be lower grade. Conclusion: Double reading with arbitration reduces recall and increases cancer detection compared to single reading. Cancers detected only by the second reader were smaller, lower grade, and had less nodal involvement

Identification of single nucleotide polymorphisms from the transcriptome of an organism with a whole genome duplication

BACKGROUND: The common ancestor of salmonid fishes, including rainbow trout (Oncorhynchus mykiss), experienced a whole genome duplication between 20 and 100 million years ago, and many of the duplicated genes have been retained in the trout genome. This retention complicates efforts to detect allelic variation in salmonid fishes. Specifically, single nucleotide polymorphism (SNP) detection is problematic because nucleotide variation can be found between the duplicate copies (paralogs) of a gene as well as between alleles. RESULTS: We present a method of differentiating between allelic and paralogous (gene copy) sequence variants, allowing identification of SNPs in organisms with multiple copies of a gene or set of genes. The basic strategy is to: 1) identify windows of unique cDNA sequences with homology to each other, 2) compare these unique cDNAs if they are not shared between individuals (i.e. the cDNA is homozygous in one individual and homozygous for another cDNA in the other individual), and 3) give a “SNP score” value between zero and one to each candidate sequence variant based on six criteria. Using this strategy we were able to detect about seven thousand potential SNPs from the transcriptomes of several clonal lines of rainbow trout. When directly compared to a pre-validated set of SNPs in polyploid wheat, we were also able to estimate the false-positive rate of this strategy as 0 to 28% depending on parameters used. CONCLUSIONS: This strategy has an advantage over traditional techniques of SNP identification because another dimension of sequencing information is utilized. This method is especially well suited for identifying SNPs in polyploids, both outbred and inbred, but would tend to be conservative for diploid organisms

Bounds on Lorentz and CPT Violation from the Earth-Ionosphere Cavity

Electromagnetic resonant cavities form the basis of many tests of Lorentz invariance involving photons. The effects of some forms of Lorentz violation scale with cavity size. We investigate possible signals of violations in the naturally occurring resonances formed in the Earth-ionosphere cavity. Comparison with observed resonances places the first terrestrial constraints on coefficients associated with dimension-three Lorentz-violating operators at the level of 10^{-20} GeV.Comment: 8 pages REVTe

Bird evolution: testing the Metaves clade with six new mitochondrial genomes

Background Evolutionary biologists are often misled by convergence of morphology and this has been common in the study of bird evolution. However, the use of molecular data sets have their own problems and phylogenies based on short DNA sequences have the potential to mislead us too. The relationships among clades and timing of the evolution of modern birds (Neoaves) has not yet been well resolved. Evidence of convergence of morphology remain controversial. With six new bird mitochondrial genomes (hummingbird, swift, kagu, rail, flamingo and grebe) we test the proposed Metaves/Coronaves division within Neoaves and the parallel radiations in this primary avian clade. Results Our mitochondrial trees did not return the Metaves clade that had been proposed based on one nuclear intron sequence. We suggest that the high number of indels within the seventh intron of the β-fibrinogen gene at this phylogenetic level, which left a dataset with not a single site across the alignment shared by all taxa, resulted in artifacts during analysis. With respect to the overall avian tree, we find the flamingo and grebe are sister taxa and basal to the shorebirds (Charadriiformes). Using a novel site-stripping technique for noise-reduction we found this relationship to be stable. The hummingbird/swift clade is outside the large and very diverse group of raptors, shore and sea birds. Unexpectedly the kagu is not closely related to the rail in our analysis, but because neither the kagu nor the rail have close affinity to any taxa within this dataset of 41 birds, their placement is not yet resolved. Conclusion Our phylogenetic hypothesis based on 41 avian mitochondrial genomes (13,229 bp) rejects monophyly of seven Metaves species and we therefore conclude that the members of Metaves do not share a common evolutionary history within the Neoaves

Select Metal and Metalloid Surveillance of Free-ranging Eastern Box Turtles from Illinois and Tennessee

The Eastern box turtle has been proposed as a biomonitor because it is long lived, relies on the environment for food and water, and has a small home range. To establish this designation, ISTC partnered with the Illinois Natural History Survey, the College of Veterinary Medicine at the University of Illinois, and the Clinch River Environmental Studies Organization. Plasma samples from 273 free-range box turtles were collected in 2011 and 2012 in Tennessee and Illinois. Full results reported in Allender, Matthew C., et al (2015). "Select metal and metalloid surveillance of free-ranging Eastern box turtles from Illinois and Tennessee (Terrapene carolina carolina)." Ecotoxicology 24, 1269–1278. https://doi.org/10.1007/s10646-015-1498-5Ope

Blending Geospatial Technology and Traditional Ecological Knowledge to Enhance Restoration Decision-Support Processes in Coastal Louisiana

More informed coastal restoration decisions have become increasingly important given limited resources available for restoration projects and the increasing magnitude of marsh degradation and loss across the Gulf Coast. This research investigated the feasibility and benefits of integrating geospatial technology with the traditional ecological knowledge (TEK) of an indigenous Louisiana coastal population to assess the impacts of current and historical ecosystem change on community viability. The primary goal was to provide coastal resource managers with a decision-support tool that allows for a more comprehensive method of assessing localized ecological change in the Gulf Coast region, which can also benefit human community sustainability. Using remote sensing (RS) and geographic information systems (GIS) mapping products, integrated with a coastal community’s TEK to achieve this goal, the research team determined a method for producing vulnerability/sustainability mapping products for an ecosystem-dependent livelihood base of a coastal population based on information derived from RS imagery prioritized with TEK. This study also demonstrates how such an approach can engage affected community residents who are interested in determining and addressing the causes and mitigating the decline of marsh habitat. Historical image data sets of the study area were acquired to understand evolution of land change to current conditions and project future vulnerability. Image-processing procedures were developed and applied to produce maps that detail land change in the study area at time intervals from 1968 to 2009. This information was combined in a GIS with acquired TEK and scientific data sets relating to marsh vegetation health and vulnerability characteristics to produce mapping products that provide new information for use in the coastal restoration decision-making process. This information includes: (1) marsh areas that are most vulnerable; and (2) the areas that are most significant to community sustainability

Biophysical Measurements of Cells, Microtubules, and DNA with an Atomic Force Microscope

Atomic force microscopes (AFMs) are ubiquitous in research laboratories and have recently been priced for use in teaching laboratories. Here we review several AFM platforms (Dimension 3000 by Digital Instruments, EasyScan2 by Nanosurf, ezAFM by Nanomagnetics, and TKAFM by Thorlabs) and describe various biophysical experiments that could be done in the teaching laboratory using these instruments. In particular, we focus on experiments that image biological materials and quantify biophysical parameters: 1) imaging cells to determine membrane tension, 2) imaging microtubules to determine their persistence length, 3) imaging the random walk of DNA molecules to determine their contour length, and 4) imaging stretched DNA molecules to measure the tensional force.Comment: 29 page preprint, 7 figures, 1 tabl

HST Imaging of the Host Galaxies of High Redshift Radio-Loud Quasars

We present rest-frame UV and Ly-alpha images of spatially-resolved structures around five high-redshift radio-loud quasars obtained with the WFPC2 camera on the Hubble Space Telescope. We find that all five quasars are extended and this "fuzz" contains ~5-40% of the total continuum flux and 15-65% of the Ly-alpha flux within a radius of about 1.5 arcsec. The rest-frame UV luminosities of the hosts are log lambda P_lambda = 11.9 to 12.5 solar luminosities (assuming no internal dust extinction), comparable to the luminous radio galaxies at similar redshifts and a factor 10 higher than both radio-quiet field galaxies at z~2-3 and the most UV-luminous low redshift starburst galaxies. The Ly-alpha luminosities of the hosts are (in the log) approximately 44.3-44.9 erg/s which are also similar to the those of luminous high redshift radio galaxies and considerably larger than the Ly-alpha luminosities of high redshift field galaxies. To generate the Ly-alpha luminosities of the hosts would require roughly a few percent of the total observed ionizing luminosity of the quasar. We find good alignment between the extended Ly-alpha and the radio sources, strong evidence for jet-cloud interactions in two cases, again resembling radio galaxies, and what is possibly the most luminous radio-UV synchrotron jet in one of the hosts at z=2.110.Comment: 36 pages (latex, aas macros), 3 figures (3 gif and 10 postscript files), accepted for publication in the the Astrophysical Journal Supplement Serie