Is there a role for femoral offset restoration during total hip arthroplasty? A systematic review

Benefits of femoral offset restoration during total hip arthroplasty should be the reduction of bearing surfaces wear, implant loosening and dislocation rates. Modular neck stems ensure offset customization but fretting corrosion and catastrophic failures are well-documented complications. Since clinical evidences are needed to substantiate the effectiveness of femoral offset restoration and promote modular neck choice, we systematically reviewed the literature to ascertain whether femoral offset itself has a proven clinical influence: (1) on bearing surfaces wear, (2) implant loosening, (3) and dislocation rates. A systematic literature screening was conducted to find papers dealing with the influence of femoral offset on wear, dislocation and loosening, including articles with conventional radiographic femoral offset assessment and with comparative design. Observational studies, case reports, instructional course lectures, cadaveric and animal studies as well as biomechanical studies, letters to the editor, surgical techniques or technical notes were all excluded. No limits about publication date were supplied but only papers in English were taken into account. Data were extracted into an anonymous spreadsheet. Offset values, dislocation rates, wear rates, follow-up and surgical approaches were all detailed. Ten manuscripts were finally selected. A statistically significant correlation between femoral offset restoration and the reduction of conventional ultrahigh-molecular-weight polyethylene wear was found in two out of three papers investigating this issue, but no correlations were found between femoral offset and dislocation rates or implant loosening. Femoral offset modification influences ultrahigh-molecular-weight polyethylene liners wear, but no correlation was found with dislocation rates or implant loosening. Advantages on wear can be counterbalanced by the use of hard bearing surfaces or highly cross-linked polyethylene liners, besides the availability of larger femoral heads improving implant stability further reduces the importance of femoral offset restoration by means of modularity. We believe that efforts in restoring femoral offset during total hip arthroplasty do not translate into tangible clinical profits and consequently, we do not advise the routinely usage of modular neck stems in total hip arthroplasty.

LEVEL OF EVIDENCE

level III, systematic review of case-control studies.

Intraoperative diagnosis of Staphylococcus aureus and coagulase-negative Staphylococcus using Xpert MRSA/SA SSTI assay in prosthetic joint infection

The aim of this prospective study was to evaluate the performance of the Polymerase Chain Reaction (PCR) tool Xpert MRSA/SA SSTI test (Cepheid, Sunnyvale, CA, USA) on periprosthetic samples from a cohort of patients with suspected prosthetic joint infection (PJI). Seventy adult patients were included in this prospective study. On the basis of the preoperative evaluation, 39 patients were clinically considered to have a PJI, whereas 31 were presumed to suffer from an aseptic mobilization of the implant. Xpert MRSA/SA SSTI identified 4 out of 4 MRSA, 7 out of 7 MSSA, and 14 out of 16 methicillin resistant CoNS. Among the 31 patients not having a PJI, the rapid PCR did not find any bacteria among those identifiable, thus demonstrating an excellent performance in terms of specificity. Statistical analysis of the analytical performance showed a high correlation (p<0.001) between the result of Xpert MRSA/SA SSTI and culture. Xpert MRSA/SA SSTI assay is a novel, yet well known, rapid and accurate method for the identification of different species of staphylococci. The test can be used with peri-operative samples thus dramatically improving the diagnostic sensitivity. In addition, thanks to the very short turnaround time the use of Xpert assay can modify the clinical management of patients suffering from PJI during the ongoing operative procedure.

Complex effective index in graphene-silicon waveguides

We report for the first time and characterize experimentally the complex optical conductivity of graphene on silicon photonic waveguides. This permits us to predict accurately the behavior of photonic integrated devices encompassing graphene layers. Exploiting a Si microring add/drop resonator, we show the effect of electrical gating of graphene on the complex effective index of the waveguide by measuring both the wavelength shift of the resonance and the change in the drop peak transmission. Due to electro-refractive effect of graphene a giant (>10^-3) change in the effective index is demonstrated for the first time on Si photonics waveguides and this large effect will crucially impact performances and consumption of Si photonics devices. We confirmed the results by two independent experiments involving two different gating schemes: Si gating through the ridge waveguide, and polymer-electrolyte gating. Both the experiments demonstrate a very large phase effect in good agreement with numerical calculations. The reported results validate the Kubo model for the case of graphene-Si photonics interfaces and for propagation in this type of waveguide. This is fundamental for the next design and fabrication of future graphene-silicon photonics devices.

Wide-band polarization controller for Si photonic integrated circuits

A circuit for the management of any arbitrary polarization state of light is demonstrated on an integrated silicon (Si) photonics platform. This circuit allows us to adapt any polarization into the standard fundamental TE mode of a Si waveguide and, conversely, to control the polarization and set it to any arbitrary polarization state. In addition, the integrated thermal tuning allows kilohertz speed which can be used to perform a polarization scrambler. The circuit was used in a WDM link and successfully used to adapt four channels into a standard Si photonic integrated circuit.

Inpatient pulmonary rehabilitation: does it make sense?

Among the nonpharmacological therapies, pulmonary rehabilitation (PR) is particularly appropriate for patients with chronic respiratory impairment who, despite any optimal drug management, are still symptomatic and experience restriction in every day activities. Pulmonary rehabilitation performed in inpatient, outpatient, or home settings demonstrates short–and long–term clinical efficacy. Although disease severity does not inherently dictate candidacy for exercise training, the degree of physiological and functional impairment may influence setting in which the training should occur. Therefore, inpatient rehabilitation is generally best–suited for the most sick and most disabled patients. The overall results from the literature confirm that the inpatient setting for a PR program is a feasible option and does not necessarily result in higher direct costs when balanced against duration and effectiveness in terms of improved outcomes.

High responsivity SiGe heterojunction phototransistor on silicon photonics platform

We report on a novel near infrared SiGe phototransistor fabricated by a standard silicon photonics foundry. The device is first investigated by simulations. The fabricated devices are characterized in terms of current-voltage characteristics at different optical power. Typical phototransistors exhibit 1.55µm record responsivity at low optical power exceeding 232A/W and 42A/W at 5V and 1V bias, respectively. A differential detection scheme is also proposed for the dark current cancellation to significantly increase the device sensitivity.

Effects of an acute high-intensity interval training protocol on plasma viscosity

AIM

High-intensity interval training (HIT) is an exercise model that has been seen to cause similar muscle adaptations and improvements in exercise performance to other traditional exercise models. This study aimed to examine the effects of low-volume HIT exercise on plasma viscosity (PV).

METHODS

Ten healthy male subjects (25.80±3.39 years) randomly performed a HIT running protocol (2-min warm up at 8 km/h, 5x2-min bouts at 90% maximal heart rate, separated by 2-min at 8 km/h, finished with another 2-min period at 8 km/h) or an aerobic (AER) running exercise (60'at 55% VO2max). Blood samples were drawn before and after exercise, and after 30-minute recovery. PV, hematocrit (Hct), fibrinogen, total proteins, triglycerides, total-cholesterol and glucose levels were analyzed. Plasma volume loss during exercise was calculated.

RESULTS

PV rose after HIT (P<0.05) while Hct rose after both protocols. Plasma volume loss was higher after HIT (-6.35±3.47%) than after AER (-3.11±2.49%) (P=0.045). Total-proteins (P<0.001), triglycerides (P=0.013), total-cholesterol (P<0.001) and glucose (P=0.001) concentrations increased after HIT. After AER no statistically significant differences were found in plasma constituents concentrations.

CONCLUSION

A low-volume HIT session causes a sufficient loss in plasma volume that leads to significantly incremented plasma constituents' concentrations and, therefore, a mild transient rise in PV.

'Kitchen and cooking,' a serious game for mild cognitive impairment and Alzheimer's disease: a pilot study

Recently there has been a growing interest in employing serious games (SGs) for the assessment and rehabilitation of elderly people with mild cognitive impairment (MCI), Alzheimer’s disease (AD), and related disorders. In the present study we examined the acceptability of ‘Kitchen and cooking’ – a SG developed in the context of the EU project VERVE (http://www.verveconsortium.eu/) – in these populations. In this game a cooking plot is employed to assess and stimulate executive functions (such as planning abilities) and praxis. The game is installed on a tablet, to be flexibly employed at home and in nursing homes. Twenty one elderly participants (9 MCI and 12 AD, including 14 outpatients and 7 patients living in nursing homes, as well as 11 apathetic and 10 non-apathetic) took part in a 1-month trail, including a clinical and neuropsychological assessment, and 4-week training where the participants were free to play as long as they wanted on a personal tablet. During the training, participants met once a week with a clinician in order to fill in self-report questionnaires assessing their overall game experience (including acceptability, motivation, and perceived emotions). The results of the self reports and of the data concerning game performance (e.g., time spent playing, number of errors, etc) confirm the overall acceptability of Kitchen and cooking for both patients with MCI and patients with AD and related disorders, and the utility to employ it for training purposes. Interestingly, the results confirm that the game is adapted also to apathetic patients.

Hemoconcentration induced by exercise: Revisiting the Dill and Costill equation

The Dill and Costill equation is used to estimate the exercise-induced hemoconcentration. However, this calculation requires drawing an extra whole-blood sample, which cannot be frozen and has to be analyzed with dedicate instrumentation in a relative short time. The aim of the present study was to explore the usefulness of some serum biochemical parameters to estimate hemoconcentration induced by exhaustive exercise. Fourteen healthy male subjects (19-34 years) performed a15-min running test at 110% of anaerobic threshold speed. Hemoglobin, hematocrit, brain natriuretic peptide (BNP), creatinine, gamma-glutamyltransferase (GGT), total-proteins, albumin, total calcium (Ca), K(+), Na(+), and Cl(-) were determined in blood samples taken before, after exercise, and after a 30-min recovery period. Plasma volume loss (ΔPV) was calculated by Dill and Costill equation. At post-exercise and after recovery, the percentage increments of total-proteins, albumin, GGT and Ca correlated significantly with ΔPV. Bland-Altman analyses showed that correcting BNP, creatinine, and K(+) concentration by Ca percentage increments yield biases and limits of agreement that are acceptable when compared with Dill and Costill equation correction. Ca concentration may be used as a hemoconcentration biomarker in high-intensity exercise, which would allow scientists and physicians avoid extra costs, facilitate in-field research, and delayed estimation of hemoconcentration using stored serum samples.

Exercise effects on erythrocyte deformability in exercise-induced arterial hypoxemia

Exercise-induced arterial hypoxemia (EIAH) is often found in endurance-trained subjects at high exercise intensity. The role of erythrocyte deformability (ED) in EIAH has been scarcely explored. We aimed to explore the role of erythrocyte properties and lactate accumulation in the response of ED in EIAH. ED was determined in 10 sedentary and in 16 trained subjects, both before and after a maximal incremental test, and after recovery, along with mean corpuscular volume (MCV) and red blood cell lactate concentrations. EIAH was found in 6 trained subjects (∆SaO2=-8.25±4.03%). Sedentary and non-EIAH trained subjects showed reduced ED after exercise, while no effect on ED was found in EIAH trained subjects. After exercise, lactate concentrations rose and MCV increased equally in all groups. ED is strongly driven by cell volume, but the different ED response to exercise in EIAH shows that other cellular mechanisms may be implicated. Interactions between membrane and cytoskeleton, which have been found to be O2-regulated, play a role in ED. The drop in SaO2 in EIAH subjects can improve ED response to exercise. This can be an adaptive mechanism that enhances muscular and pulmonary perfusion, and allows the achievement of high exercise intensity in EIAH despite lower O2 arterial transport.

Inconsistency in circulating irisin levels: what is really happening?

The discovery of irisin as a novel and promising peptidic hormone for the treatment of obesity and diabetes has recently been reported. As a result, great hopes have been raised based on this finding, hypothesizing that irisin might provide additional benefits, not only for obesity and diabetes, but also for a wide range of pathological conditions requiring therapeutical and clinical attention. However, controversial results and conclusions on circulating irisin concentrations and correlations with other variables, including its role in metabolism, have recently been reported. Although laboratory assessment of irisin by ELISA is easily available and may provide interesting information for therapeutics and clinical practice, the heterogeneous and often discrepant results published so far, raise serious concerns about its measurement, indicating that it may still not be ready for use or whether irisin really exists. We highlight here some aspects on these discrepancies and contradictions, and put forward their implications.

Idiopathic pulmonary fibrosis clustering based on cilium gene expression: profiling a new paradigm

Idiopathic pulmonary fibrosis (IPF), the commonest form of the interstitial lung diseases identifies a specific form of chronic, progressive fibrosing interstitial pneumonia, occurring primarily in older adults, and limited to the lungs. IPF represents an unsolved health problem with an urgent medical need due to lack of effective therapies. Although precise IPF etiology remains elusive, during the past decade there has been a shift away from the pathogenetic theory of generalized inflammation progressing to a paradigm of disordered fibroproliferation and alveolar epithelial cell function. A better understanding of the molecular mechanisms driving IPF fibroblasts proliferation is mandatory to provide insights into the pathogenesis, and to identify highly reproducible biomarkers for disease onset and progression. In this review we aim to discuss and analyze the findings recently published by Yang et al. on Thorax, which reported a strong molecular signature as-sociated with the expression of cilium genes that divides IPF/ usual interstitial pneumonia into two subtypes, one with increased cilium gene expression and one with low expression of cilium genes. The study presents a number of methodology limitations, mainly related to samples characterization and to a general overstatement of the conclusions from class clustering analysis. Nevertheless, the study clearly demonstrates ‑ for the first time ‑ that the cilium apparatus is activated in microscopic honeycombing. In such setting, cilia are likely to act as signaling "machine" which cooperates in promoting proliferative and regenerative cellular processes. Although preliminary, these results sustain a rationale to develop further investigations to confirm the impact of cilium gene expression in IPF with the final perspective of therapeutic intervention.

Resurrection of hip resurfacing: what is the evidence?

Total hip resurfacing has long been conceptually attractive to both surgeons and patients. However, historically it has been plagued by limited durability and marked acetabular bone loss. The recent development of wear-resistant bearings, such as metal-on-metal, has led to renewed interest in hip resurfacing in the orthopedic community. Several resurfacing implants have been designed and positive results, particularly in young patients, have been reported. Although comparative studies of hip resurfacing and standard total hip replacement are still lacking, we believe that there is now evidence to demonstrate that this surgical concept deserves consideration, particularly when treating young patients with hip diseases.

The effect of anticoagulant therapy for idiopathic pulmonary fibrosis in real life practice

BACKGROUND

IPF is a common form of interstitial lung disease for which there is no effective therapy and usually results in death. Two previous contradictory studies showed anticoagulant therapy  to be associated with both improved and worsened survival, respectively.

OBJECTIVE

The objective of this retrospective cohort study was to evaluate the effect of anticoagulant therapy on the survival and disease progression of patients with idiopathic pulmonary fibrosis (IPF) in real clinical practice.

METHODS

We compared the clinical characteristics, time to disease progression, incidence of acute exacerbation, and survival of 25 (20%) IPF patients receiving anticoagulant therapy to the remaining 97 IPF patients not receiving anticoagulant therapy. In addition we conducted a sensitivity analysis using as comparator a group of 25 patients matched by age, sex, functional impairment, cardiac comorbidities and pulmonary hypertension.

RESULTS

Patients on anticoagulant therapy had a worse 1- and 3-year survival (84% and 53% versus 89% and 64% in the non-anticoagulant group, respectively), a difference that persisted after adjusting for age and comorbidities (hazard ratio 3.1 - 95% confidence interval, 1.4 to 7.0; p=0.006) and after comparison with the matched group (adjusted HR=4.8, 95% CI: 1.8-12.8; p=0.002). IPF patients on anticoagulant therapy had a shorter interval to disease progression ( 0.7 years versus 1.6 years, adjusted HR 2.2 -95% CI, 0.96 to 5.1; p=0.063) confirmed also in the analysis with matched subgroups (HR=2.7 (95% CI: 1.2-6.5); p=0.023). The incidence of acute exacerbations did not differ in the two groups (22% versus 23%). Two patients (8%) experienced anticoagulant treatment related complications and included an episode of hemorrhagic shock.

CONCLUSION

In this retrospective study patients treated with anticoagulants had a worse survival and a shorter interval to disease progression. This support the recent finding that warfarin worsen the respiratory status and survival of IPF patients.

Functional performance of a total ankle replacement: thorough assessment by combining gait and fluoroscopic analyses

BACKGROUND

A thorough assessment of patients after total ankle replacement during activity of daily living can provide complete evidence of restored function in the overall lower limbs and replaced ankle. This study analyzes how far a possible restoration of physiological mobility in the replaced ankle can also improve the function of the whole locomotor apparatus.

METHODS

Twenty patients implanted with an original three-part ankle prosthesis were analyzed 12 months after surgery during stair climbing and descending. Standard gait analysis and motion tracking of the components by three-dimensional fluoroscopic analysis were performed on the same day using an established protocol and technique, respectively.

FINDINGS

Nearly physiological ankle kinematic, kinetic and electromyography patterns were observed in the contralateral side in both motor activities, whereas these patterns were observed only during stair climbing in the operated side. Particularly, the mean ranges of flexion at the replaced ankle were 13° and 17° during stair climbing and descending, respectively. Corresponding 2.1 and 3.1mm antero/posterior meniscal-to-tibial translations were correlated with flexion between the two metal components (p<0.05). In addition, a larger tibiotalar flexion revealed by fluoroscopic analysis resulted in a physiological hip and knee moment.

INTERPRETATION

The local and global functional performances of these patients were satisfactory, especially during stair climbing. These might be associated to the recovery of physiological kinematics at the replaced ankle, as also shown by the consistent antero/posterior motion of the meniscal bearing, according to the original concepts of this ankle replacement design.