Temporary vena cava filters in the prevention of pulmonary embolism during total hip arthroplasty

Thromboembolism constitutes one of the most dangerous complications during the immediate postoperative period of prosthetic surgery. Pharmacological prophylaxis and mechanical vascular compression are not always sufficient to protect from this surgical complication. In patients at greatest risk for thromboembolism, often with a positive history for pulmonary embolism, temporary vena cava filters may be used to reduce the incidence of vascular and pulmonary complications. However useful, these filters cannot be routinely used in orthopedic surgery. We present our results with the use of Filcard RFO2 vena cava filters in an open, randomized study of 30 patients

Posterior-stabilized (PS) total knee arthroplasty: a matched pair analysis of a classic and its evolutional design

Background: Total knee arthroplasty (TKA) designs continue to be modified to optimize patient's outcome. This study was designed to compare clinical and radiological results of classic worldwide used TKA posterior-stabilized (PS) design to those of its recent evolution. Methods: A consecutive group of 100 patients undergoing TKA using a classic cemented fixed-bearing PS TKA system was matched by age, gender, body max index to 100 patients having the newer cemented fixed-bearing PS design, both by the same manufacturer. Patients were assessed preoperatively, at 12 months and at 24 months minimum follow-up (range, 24-46) in a standard prospective fashion. The outcome assessments used were the Oxford Knee Score, the Knee Society Score, range of motion, and a satisfaction survey. A 2-sample t test comparing the 2 groups was performed. Results: No patients were lost at follow-up. At 2-year follow-up, differences in clinical and radiological Knee Society Score (P = .09), Oxford Score (P = .08), and overall satisfaction rate did not reach statistical significance. Implant group 2 showed a statistically significant decrease in postoperative anterior knee pain (P = .006). At final follow-up, 16% of group 1 knees achieved > 130° flexion compared with 37% in group 2 (P = .0009). There were 2 revisions for any reason in group 1 and none in group 2. Conclusions: Design modifications applied to the newer TKA system allowed greater flexion and lower patellofemoral complications but did not appear to achieve better overall clinical scores

A severe infective endocarditis successfully treated with linezolid

Despite significant improvements in surgical and medical therapy, prosthetic valve endocarditis (PVE) is a diagnostic and therapeutic challenge and is often associated with a severe prognosis. We report a case of a 59-year-old woman, with  PVE and bacterial endocarditis (Streptococcus bovis) successfully treated with linezolid. Linezolid is a bacteriostatic oxazolidinone antibiotic that has been proven to be effective for the treatment of patients with pneumonia, skin and soft tissue infections, and infections due to Gram-positive cocci. Linezolid is not yet recognised as a standard therapy for infective endocarditis, but its use becomes a necessity when infection is due to multidrug-resistant microorganisms

Relationship between tibial baseplate design and rotational alignment landmarks in primary total knee arthroplasty

This study evaluated the influence of modern tibial baseplate designs when using the anterior tibial cortex as a primary rotational landmark for the tibial baseplate in TKA. Eighty patients undergoing TKA were randomized in two groups. Group 1 included 25 females and 15 males receiving a posterior-stabilized (PS) symmetric tibial baseplate while Group 2 included 24 females and 16 males receiving a PS anatomical tibial component. Identical surgical technique, including the use of the surgical transepicondylar femoral axis (sTEA) and the anterior tibial cortex (“Curve-on-Curve”) as rotational alignment landmarks, was used. All patients underwent CT evaluation performed with the knee in full extension. Three observers independently measured the rotational alignment of the tibial component in relation to the sTEA. The rotational alignment of the symmetric baseplate showed an average external rotation of 1.3° (minimum 5°, maximum −1°): 91% of the knees showed 0 ± 3° with respect to the surgical sTEA, being internally rotated in 20%. The rotational alignment of the anatomical baseplate showed an average external rotation of 4.1° (minimum 0.4°, maximum 8.9°): only 47.5% of the knees showed 0 ± 3°, being externally rotated in 100%. The difference between the two groups was statistically significant. This study confirms the reliability of the “Curve-on-Curve” technique as an adequate rotational alignment anatomical landmark in TKA: the use of an asymmetric tibial baseplate might lead to external rotation of the tibial component when this technique is intraoperatively chosen

Evidence of major dry mergers at M* > 2 x 10^11 Msun from curvature in early-type galaxy scaling relations?

For early-type galaxies, the correlations between stellar mass and size, velocity dispersion, surface brightness, color, axis ratio and color-gradient all indicate that two mass scales, M* = 3 x 10^10 Msun and M* = 2 x 10^11 Msun, are special. The smaller scale could mark the transition between wet and dry mergers, or it could be related to the interplay between SN and AGN feedback, although quantitative measures of this transition may be affected by morphological contamination. At the more massive scale, mean axis ratios and color gradients are maximal, and above it, the colors are redder, the sizes larger and the velocity dispersions smaller than expected based on the scaling at lower M*. In contrast, the color-sigma relation, and indeed, most scaling relations with sigma, are not curved: they are well-described by a single power law, or in some cases, are almost completely flat. When major dry mergers change masses, sizes, axis ratios and color gradients, they are expected to change the colors or velocity dispersions much less. Therefore, the fact that scaling relations at sigma > 150 km/s show no features, whereas the size-M*, b/a-M*, color-M* and color gradient-M* relations do, suggests that M* = 2 x 10^11 Msun is the scale above which major dry mergers dominate the assembly histories of early-type galaxies.Comment: 5 pages, 3 figures. Accepted for publication in MNRA

The age dependence of the size-stellar mass relation and some implications

We use a sample of about 48,000 SDSS early-type galaxies to show that older galaxies have smaller half-light radii re and larger velocity dispersions sigma than younger ones of the same stellar mass Mstar. We use the age-corrected luminosity Lcorr as a proxy for Mstar to minimize biases: below Lcorr~1e11 Lsun, galaxies with age ~11 Gyrs have re smaller by 40% and sigma larger by 25%, compared to galaxies that are ~4 Gyrs younger. The sizes and velocity dispersions of more luminous galaxies vary by less than 15%, whatever their age, a challenge for current galaxy formation models. A closer check reveals that the lowering in the dispersion is caused by older galaxies that show a significant departure from the re--Lcorr and sigma--Lcorr relations at high Lcorr. Such features might find an explanation in models where more massive galaxies undergo more minor mergers than less massive galaxies at late times, thus causing a break in the homology. In terms of the Fundamental Plane of early-type galaxies, the data indicate that all galaxies show a significant and similar increase in the dynamical-to-stellar mass ratio with increasing mass, independent of their age. However, older galaxies have smaller Mdyn/Mstar ratios than objects which formed more recently. These findings may suggest that lower mass galaxies and, at fixed stellar mass, higher redshift galaxies, formed from gas-richer progenitors, thus underwent more dissipation and contraction.Comment: Accepted by MNRAS Lette

Microfracture and Hydrogel Scaffolds for the Treatment of Osteochondral Injuries of the Knee: Clinical Results at 4 Years Follow-Up

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Curvature in the color-magnitude relation but not in color-sigma: Major dry mergers at M* > 2 x 10^11 Msun?

The color-magnitude relation of early-type galaxies differs slightly but significantly from a pure power-law, curving downwards at low and upwards at large luminosities (Mr>-20.5 and Mr<-22.5). This remains true of the color-size relation, and is even more apparent with stellar mass (M* < 3x10^10 Msun and M* > 2x10^11 Msun). The upwards curvature at the massive end does not appear to be due to stellar population effects. In contrast, the color-sigma relation is well-described by a single power law. Since major dry mergers change neither the colors nor sigma, but they do change masses and sizes, the clear features observed in the scaling relations with M*, but not with sigma > 150 km/s, suggest that M* > 2x10^11 Msun is the scale above which major dry mergers dominate the assembly history. We discuss three models of the merger histories since z ~ 1 which are compatible with our measurements. In all three models, dry mergers are responsible for the flattening of the color-M* relation at M* > 3x10^10 Msun - wet mergers only matter at smaller masses. At M* > 2 x 10^11 Msun, the merger histories in one model are dominated by major rather than minor dry mergers, as suggested by the axis ratio and color gradient trends. In another, although both major and minor mergers occur at the high mass end, the minor mergers contribute primarily to the formation of the ICL, rather than to the mass growth of the central massive galaxy. A final model assumes that the reddest objects were assembled by a mix of major and minor dry mergers.Comment: 22 pages, 22 figures and 3 tables. Accepted for publication in MNRA

The Demography of Super-Massive Black Holes: Growing Monsters at the Heart of Galaxies

Supermassive black holes (BHs) appear to be ubiquitous at the center of all galaxies which have been observed at high enough sensitivities and resolution with the Hubble Space Telescope. Their masses are found to be tightly linked with the masses and velocity dispersions of their host galaxies. On the other hand, BHs are widely held to constitute the central engines of quasars and active galactic nuclei (AGN) in general. It is however still unclear how BHs have grown, and whether they have co-evolved with their hosts. In this Review I discuss how, in ways independent of specific models, constraints on the growth history of BHs and their host galaxies have been set by matching the statistics of local BHs to the emissivity, number density, and clustering properties of AGNs at different cosmological epochs. I also present some new results obtained through a novel numerical code which evolves the BH mass function and clustering adopting broad distributions of Eddington ratios. I finally review BH evolution in a wider cosmological context, connecting BH growth to galaxy evolution.Comment: 70 pages. New Astronomy Reviews, in pres