Analysis of complications in 97 periprosthetic Vancouver B2 fractures treated either by internal fixation or revision arthroplasty.

INTRODUCTION: The treatment of Vancouver B2 periprosthetic fractures after hip arthroplasty is still a matter of debate. Revision Arthroplasty (RA) was long thought to be the treatment of choice, however several recent papers suggested that Open Reduction and Internal Fixation (ORIF) is a viable option for selected B2 fractures. Complication rates of 14-26% have been reported following surgical treatment of B2 fractures. No significant difference between RA and ORIF in the complication rates nor in the functional outcome was observed. METHOD: We conducted a retrospective analysis of 97 consecutive Vancouver B2 fractures treated according to the algorithm at our institution from 2007 to 2020 and recorded complications and patient specific data. RESULT: From the 97 patient, 45 fractures were treated with RA while 52 fractures were treated with ORIF. Thirteen patients in the RA group had a complication that needed revision (28%) and 11 patients in the ORIF group needed revision (21%). There was no significant difference between complication rates. The reason for failure in the 13 RA patients were infection (n = 4), stem subsidence (n = 1), refracture after a new fall (n = 3), secondary dislocation of the greater trochanter (n = 1) and dislocation (n = 4). The reason for failure in the 11 ORIF patients that were revised were infection (n = 5), persistent symptomatic stem loosening (n = 3) and refracture (n = 3) after a new fall. CONCLUSION: ORIF can be used to revise cemented and non-cemented shafts in more than half of Vancouver B2 fractures with no difference in complication rates when compared to RA. A periprosthetic fracture around the hip has a 21-28% risk of a re-operation after revision surgery with infection and re-fracture after a new fall being the most frequent cause of re-operation.

Management of acute periprosthetic knee infection: a comparison of arthroscopic and open debridement.

INTRODUCTION: In acute periprosthetic knee infections, debridement and implant retention (DAIR) is the preferred treatment prior to one- and two-stage revisions. The aim of this study is to compare the outcomes of arthroscopic and open debridement of infected primary total knee arthroplasties (TKA). MATERIAL AND METHODS: We analyzed clinical, laboratory, and antibiotic treatment data, collected in patients with periprosthetic knee infection treated with DAIR at a Swiss Level 1 orthopedic and trauma center over a 10-year period between January 2005 and May 2015. Inclusion criteria were primary total knee arthroplasty and early postoperative or acute hematogenous periprosthetic joint infection (PJI). The primary endpoint was the need for further revision surgery due to persistent infection. The secondary endpoint was the prosthesis salvage in further infection surgeries. RESULTS: Forty-two patients with 44 acute or hematogenous periprosthetic knee infections were included. We recorded 20 recurrent infections (45%) in our study population: 10 (77%) out of 13 in the arthroscopic DAIR group and 10 (32%) out of 31 in the open DAIR group. Two-stage revision, meaning complete removal of the TKA, insertion of a spacer and replantation at a second stage, had to be performed in three patients treated initially arthroscopically (23%) and in six patients treated initially with an open surgical procedure (21%). CONCLUSIONS: Open debridement for acute periprosthetic knee infection shows clear benefits in terms of infection eradication and prosthesis salvage compared to arthroscopic DAIR.

Bone infection: a clinical priority for clinicians, scientists and educators.

Bone infection has received increasing attention in recent years as one of the main outstanding clinical problems in orthopaedic-trauma surgery that has not been successfully addressed. In fact, infection may develop across a spectrum of patient types regardless of the level of perioperative management, including antibiotic prophylaxis. Some of the main unknown factors that may be involved, and the main targets for future intervention, include more accurate and less invasive diagnostic options, more thorough and accurate debridement protocols, and more potent and targeted antimicrobials. The underlying biology dominates the clinical management of bone infections, with features such as biofilm formation, osteolysis and vascularisation being particularly influential. Based on the persistence of this problem, an improved understanding of the basic biology is deemed necessary to enable innovation in the field. Furthermore, from the clinical side, better evidence, documentation and outreach will be required to translate these innovations to the patient. This review presents the findings and progress of the AO Trauma Clinical Priority Program on the topic of bone infection.

[Acute coronary lithotripsy in an 83-year-old man with syncope and acute coronary syndrome]. / Akute koronare Lithotripsie bei einem 83-jährigen Mann mit Synkope und akutem Koronarsyndrom.

BACKGROUND: An 83-year-old male presented with syncope and acute coronary syndrome. An electrocardiogram (ECG) suggested left main (LM) coronary artery stenosis; angiography confirmed a heavily calcified tight LM stenosis. CLINICAL COURSE: Percutaneous coronary intervention was performed using intravascular lithotripsy and implantation of drug eluting stents with an excellent angiographic result, resolution of symptoms and ECG changes. CONCLUSION: Intravascular lithotripsy is a new and easily applicable method for heavily calcified coronary lesions. Cost-effectiveness and long-term results will define its future role.

[The Course of E-Cigarette Use in Adolescence: A Cohort Study over 18 Months]. / Der Verlauf des E-Zigarettenkonsums im Jugendalter: Eine Kohortenstudie über 18 Monate.

AIM: Description of adolescent e-cigarette use over time. METHOD: In 2017 and 2019, 261 adolescents from North Rhine-Westphalia who had used e-cigarettes at least once a month (mean age: 14.9 years; 33.5 % female) took part in a questionnaire study. RESULTS: In 2017, 84 adolescents (32.2 %) reported exclusive e-cigarette use (single users), 177 adolescents were classified as dual users (67.8 %) because they consumed a tobacco product (conventional cigarette and/or hookah) in addition to e-cigarettes. During the observation period of 18 months, 83 adolescents (31.8 %) quit nicotine products altogether. Dual users quit nicotine less often than single users (N = 39 or 22.0 % vs. N = 44 or 52.4 %, p < 0.001). Seven single users (8.3 %) did not change their behavior, 11 began to use tobacco exclusively (13.1 %), another 22 (26.2 %) started dual use. Seventy-eight dual users (44.1 %) did not change their behavior, 57 (32.1 %) switched to tobacco use only, 3 dual users (1.7 %) stopped tobacco use, but continued to use e-cigarettes. Taken together, at the end of the study, 10 (5.6 %) of the remaining 178 adolescents consumed only e-cigarettes, while 168 (94.4 %) smoked tobacco or were dual-users. CONCLUSIONS: More than two thirds of all young e-cigarette users and more than three quarters of dual users also used nicotine products 18 months later. The remaining consumers showed a less frequent stay or switch to single use, instead a more frequent use of tobacco or dual use.

[E-Cigarette Use and Later Use of Conventional Cigarettes - Results of a Prospective Observational Study over 2 Years]. / E-Zigarettenkonsum und späterer Konsum konventioneller Zigaretten.

AIM: The aim was to investigate whether e-cigarette use predicts later experimentation with conventional cigarettes. METHODS: During the 2016/2017 school year, 2,388 children and adolescents from Baden-Württemberg, Mecklenburg-Western Pomerania, North Rhine-Westphalia, Rhineland-Palatinate, Schleswig-Holstein and Saxony who had never smoked conventional cigarettes before took part in a survey over a 2-year period (mean age 11.8 years, SD = 1.21; 49.6 % female). RESULTS: At baseline, 85 pupils (3.6 %) reported that they had already tried e-cigarettes at least once. By the end of the observational period, 430 of the sample had tried conventional cigarettes (18.0 %). After statistical control for age, sex, migration background, type of school, socioeconomic status, sensation-seeking, alcohol use, and school performance, the adjusted relative risk of experimentation with conventional cigarettes was 85 % higher (adjusted relative risk = 1.85, 95 % CI [1.34 - 2.56]) for pupils who had used e-cigarettes at baseline. Further analyses revealed that the risk was higher among adolescents with low sensation-seeking scores. CONCLUSION: Among young never-smokers, experimentation with conventional cigarettes is more common in those who used e-cigarettes before than among those who have not tried e-cigarettes before. This effect seems to be stronger among adolescents who, in general, have a lower risk of starting to smoke.

[Smoking in Adolescence in England and Germany, 2001 - 2016]. / Rauchen im Jugendalter in England und Deutschland, 2001 ­â€Š2016.

AIM: To describe the smoking behavior of adolescents from England and Germany over a period of 15 years. METHODS: Eleven repeated cross-sectional surveys involving a total of 107,485 persons aged 11 to 15 years were carried out between 2001 and 2016 in England and Germany. The following data were assessed: a) the relative proportion of young people who ever smoked a conventional tobacco product, and b) the relative proportion of adolescents, who were current smokers, i. e. teenagers who smoked "occasionally" or "constantly" or "regularly". RESULTS: In the observational period, there was a significant stronger reduction in the proportion of young people who ever smoked in Germany (from 52 % to 10 %) compared to England (from 44 % to 19 %). In the same period, the proportion of young people who smoked currently dropped by 16 percentage points to 3 % in Germany and by 12 percentage points to 7 % in England (no significant difference). CONCLUSIONS: Data indicate a stronger trend towards never smoking in Germany compared to England, and a similar falling trend on "current" smoking in both countries. Causal conclusions are not possible due to the study design.

Preclinical in vivo models of fracture-related infection: a systematic review and critical appraisal.

A fracture-related infection (FRI) is an important complication that can lead to an increase in morbidity, mortality and economic costs. Preclinical in vivo models are critical in the evaluation of novel prevention and treatment strategies, yet it is important that these studies recapitulate the features of an FRI that make it such a clinical challenge. The aim of this systematic review was to survey the available preclinical models of FRIs and assess which of the key FRI-specific parameters are incorporated in these models. A comprehensive search was performed on July 1st 2017 in PubMed, Embase and Web of Science. Overall, 75 preclinical studies were identified, 97.3 % (n = 73) of which use Staphylococcus aureus as the causative microorganism. The most common mode for creation of bone instability is an osteotomy (n = 30; 40 %), followed by the creation of a defect (n = 26; 34.7 %). An actual fracture is created in only 19 studies (25.3 %). 12 (16 %) of the models include a time gap between bacterial inoculation and fixation to mimic the time-to-treatment in clinical open fracture scenarios. This systematic review reveals that animal models used in translational research on prevention and treatment of FRIs rarely incorporate all key clinical features in one model and that there is an over-representation of S. aureus in comparison to actual clinical epidemiology. To improve the relevance of these studies, existing preclinical models should be adapted or new models developed that better recapitulate the clinical condition of FRI.

Probing the Nodal Structure of Landau Level Wave Functions in Real Space.

The inversion layer of p-InSb(110) obtained by Cs adsorption of 1.8% of a monolayer is used to probe the Landau level wave functions within smooth potential valleys by scanning tunneling spectroscopy at 14 T. The nodal structure becomes apparent as a double peak structure of each spin polarized first Landau level, while the zeroth Landau level exhibits a single peak per spin level only. The real space data show single rings of the valley-confined drift states for the zeroth Landau level and double rings for the first Landau level. The result is reproduced by a recursive Green function algorithm using the potential landscape obtained experimentally. We show that the result is generic by comparing the local density of states from the Green function algorithm with results from a well-controlled analytic model based on the guiding center approach.

[Imitation of an Anderson type II dens fracture by a motion artefact in computed tomography : Four case examples]. / Imitation einer Densfraktur Typ Anderson II durch ein computertomographisches Bewegungsartefakt : Vier Fallbeispiele.

Computed tomography (CT) is the method of choice in the diagnosis and classification of odontoid fractures with a sensitivity of more than 99 % and a specificity almost equally as high. In this article we report on four cases where CT-generated motion artefacts exactly mimicked an Anderson type II fracture of the dens axis, initially leading to a wrong diagnosis. Although this seems to be a very rare event, these cases indicate that overlooked CT motion artefacts can lead to severe consequences and attention must be paid to the radiological signs outlined in this report.

[Prevalence and Correlates of Substance Use in 5,688 Vocational School Students]. / Verbreitung und Korrelate des Substanzkonsums unter 5,688 Auszubildenden an beruflichen Schulen.

OBJECTIVE: The aim of this study was to investigate the prevalence of substance use of German apprentices in vocational schools, considering socio-demographic characteristics and vocational field. METHODS: Cross-sectional study of 5,688 first year apprentices. These were 5,001 apprentices from 34 schools of the "Dual System" and 687 students from 15 vocational schools of the social and health sector. Sociodemographic characteristics and prevalence of tobacco, alcohol, cannabis, other illegal drugs, and pharmaceuticals were assessed. There was also a screening for problematic alcohol and cannabis use. The paper-pencil survey was conducted by trained research staff in 7 German federal states from September to December 2012. RESULTS: Half of the apprentices (49.9%) used tobacco in the 30 days prior to questioning, 40.7% reported daily smoking. Alcohol use in the past 30 days was reported by 68.9%, 45.0% of the sample had a positive screening result for problematic alcohol use. Prevalence rates for the use of cannabis and other illegal drugs in the last 30 days were 7.5% and 2.6%, taking pharmaceuticals was reported by 20.7%. Significant correlates of substance use were gender and socio-economic status. Differences between vocational clusters were also found, with higher average rates in service-based and commercial-technical professions. However, these differences could mostly be explained by sociodemographic differences in the composition of the vocational clusters. CONCLUSIONS: Use of psychotropic substances is a widespread activity in German apprentices. Prevalence rates are higher than in the same age total population. The highest proportion of variance was explained by differences in gender and socio-economic status.

Impact of colonoscopic screening in male and female Lynch syndrome carriers with an MSH2 mutation.

The lifetime risk of developing colorectal cancer (CRC) in Lynch syndrome (LS) carriers is very high. To determine the impact of colonoscopic screening in 54 male and 98 female MSH2 mutation carriers, outcomes were compared with 94 males and 76 females who were not screened. CRC incidence and survival in the screened group were compared to that expected, derived from the non-screened group. To correct for survivor bias, controls were matched for age at entry into screening and also for gender. In males, median age to CRC was 58 years, whereas expected was 47 years (p = 0.000), and median survival was 66 years vs 62 years (p = 0.034). In screened females, median age to CRC was 79 years compared to 57 years in the non-screened group (p = 0.000), and median survival was 80 years compared with expected of 63 years (p = 0.001). Twenty percent of males and 7% of females developed an interval CRC within 2 years of previous colonoscopy. Although colonoscopic screening was associated with decreased CRC risk and better survival, CRCs continued to occur. CRC development may be further reduced by decreasing the screening interval to 1 year and improving quality of colonoscopy.

Robust nodal structure of Landau level wave functions revealed by Fourier transform scanning tunneling spectroscopy.

Scanning tunneling spectroscopy is used to study the real-space local density of states of a two-dimensional electron system in a magnetic field, in particular within higher Landau levels. By Fourier transforming the local density of states, we find a set of n radial minima at fixed momenta for the nth Landau levels. The momenta of the minima depend only on the inverse magnetic length. By comparison with analytical theory and numerical simulations, we attribute the minima to the nodes of the quantum cyclotron orbits, which decouple in a Fourier representation from the random guiding center motion due to disorder. Adequate Fourier filtering reveals the nodal structure in real space in some areas of the sample with relatively smooth potential disorder.

Wave-function mapping of graphene quantum dots with soft confinement.

Using low-temperature scanning tunneling spectroscopy, we map the local density of states of graphene quantum dots supported on Ir(111). Because of a band gap in the projected Ir band structure around the graphene K point, the electronic properties of the QDs are dominantly graphenelike. Indeed, we compare the results favorably with tight binding calculations on the honeycomb lattice based on parameters derived from density functional theory. We find that the interaction with the substrate near the edge of the island gradually opens a gap in the Dirac cone, which implies soft-wall confinement. Interestingly, this confinement results in highly symmetric wave functions. Further influences of the substrate are given by the known moiré potential and a 10% penetration of an Ir surface resonance into the graphene layer.

Psychometric properties of the Autonomy over Tobacco Scale in German.

BACKGROUND/AIMS: We investigated the psychometric properties of a German translation of the 12-item Autonomy over Tobacco Scale (AUTOS) among 1,195 eighth-grade students. METHODS: Data for this study were collected as part of the fourth wave of data collection of the Smokefree Class Competition intervention in the Saxony-Anhalt region of Germany. Students from the control arm of the Smokefree Class Competition study who indicated that they had ever smoked 'at least a few puffs' on a cigarette were classified as ever-smokers. They self-completed questionnaires distributed by teachers. RESULTS: AUTOS scores ranged from 0 to 36 with a distribution highly skewed toward lower-response categories. Inter-item correlations ranged from 0.65 to 0.89 (mean = 0.79, SD = 0.06). Composite reliability for the AUTOS was high (Ω = 0.96) and 3 lower-order factors were also reliable (withdrawal: 0.89, psychological dependence: 0.91, cue-induced cravings: 0.87). Concurrent validity was supported by strong relationships between the AUTOS and both lifetime cigarette consumption and current smoking frequency. Youths were 18 times more likely to be current smokers (95% CI = 11.9-27.2, p < 0.001) if they endorsed any AUTOS item. CONCLUSION: The German AUTOS is reliable and valid, and the results are consistent with the English AUTOS for use with adolescents.

Probing electron-electron interaction in quantum Hall systems with scanning tunneling spectroscopy.

Using low-temperature scanning tunneling spectroscopy applied to the Cs-induced two-dimensional electron system (2DES) on p-type InSb(110), we probe electron-electron interaction effects in the quantum Hall regime. The 2DES is decoupled from bulk states and exhibits spreading resistance within the insulating quantum Hall phases. In quantitative agreement with calculations we find an exchange enhancement of the spin splitting. Moreover, we observe that both the spatially averaged as well as the local density of states feature a characteristic Coulomb gap at the Fermi level. These results show that electron-electron interaction can be probed down to a resolution below all relevant length scales.

Bistability and oscillatory motion of natural nanomembranes appearing within monolayer graphene on silicon dioxide.

The truly two-dimensional material graphene is an ideal candidate for nanoelectromechanics due to its large strength and mobility. Here we show that graphene flakes provide natural nanomembranes of diameter down to 3 nm within its intrinsic rippling. The membranes can be lifted either reversibly or hysteretically by the tip of a scanning tunneling microscope. The clamped-membrane model including van-der-Waals and dielectric forces explains the results quantitatively. AC-fields oscillate the membranes, which might lead to a completely novel approach to controlled quantized oscillations or single atom mass detection.

Providing an Evidence Base for Tissue Sampling and Culture Interpretation in Suspected Fracture-Related Infection.

BACKGROUND: The recent consensus definition for the diagnosis of fracture-related infection (FRI) includes the identification of indistinguishable microorganisms in at least 2 surgical deep-tissue specimens as a confirmatory criterion. However, this cut-off, and the total number of specimens from a patient with suspected FRI that should be sent for microbiological testing, have not been validated. We endeavored to estimate the accuracy of different numbers of specimens and diagnostic cut-offs for microbiological testing of deep-tissue specimens in patients undergoing surgical treatment for possible FRI. METHODS: A total of 513 surgical procedures in 385 patients with suspected FRI were included. A minimum of 2 surgical deep-tissue specimens were submitted for microbiological testing; 5 or more specimens were analyzed in 345 procedures (67%). FRI was defined by the presence of any confirmatory criteria other than microbiology. Resampling was utilized to model the sensitivity and specificity of diagnostic cut-offs for the number of surgical specimens yielding indistinguishable microorganisms and for the total number of specimens. The likelihood of detecting all clinically relevant microorganisms was also assessed. RESULTS: A diagnostic cut-off of at least 2 of 5 specimens with indistinguishable microorganisms identified by culture was 68% sensitive (95% confidence interval [CI], 62% to 74%) and 87% specific (95% CI, 81% to 94%) for the diagnosis of FRI. Two out of 3 specimens were 60% sensitive (95% CI, 55% to 66%) and 92% specific (95% CI, 88% to 96%). Submitting only 3 deep-tissue specimens risked missing clinically relevant microorganisms in at least 1 in 10 cases. CONCLUSIONS: The present study was the first to validate microbiological criteria for the diagnosis of FRI, supporting the current confirmatory diagnostic criteria for FRI. Analysis of at least 5 deep-tissue specimens in patients with possible FRI is recommended. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Influencing antecedents of adolescent risk-taking behaviour in elementary school: results of a 4-year quasi-experimental controlled trial.

Effects of the life skills programme 'Eigenständig werden' (Becoming independent) on life skills and on identified antecedents of adolescent health risk behaviour, childhood internalizing and externalizing behaviour were tested in an elementary school setting. A quasi-experimental controlled trial with five repeated measures was conducted. Participants were 919 students from 50 elementary schools in Saxony, Germany. Outcomes were assessed by teachers' ratings. Growth-curve models revealed that the rate of decline in internalizing and externalizing behaviour was significantly higher in the intervention group-especially for students with high baseline levels of externalizing behaviour (P < 0.01). No general programme effects on the development of skills could be found (P = 0.22). The current study provides evidence that life skills programmes in elementary school may be an effective strategy in reducing antecedents of adolescent risk-taking behaviour.