Locking plate for periprosthetic femoral fractures according to Vancouver C: Outcome and radiological subanalysis of 40 patients.

PURPOSE: Periprosthetic femoral fractures (PFF) according to type Vancouver C are less common and outcome is limited reported. Therefore, we conducted this retrospective single center study. METHODS: We performed analysis of patients who underwent open reduction and internal fixation (ORIF) with locking plates for PPF occurring distally of a primary standard hip stem. Data on demographics, revisions, fracture patterns, and mortality were evaluated. At least two years after operation, we examined outcome using the Parker and Palmer mobility score. Primary aim of this study was revision, outcome and mortality. Secondary aim was evaluation of fracture subtypes within type Vancouver C fractures. RESULTS: Between 2008 and 2020, 383 patients with periprosthetic femoral fracture after hip replacement were surgically treated according to our database. Among them, 40 patients (10.4%) with type Vancouver C fractures were enrolled for this study. The mean patient age was 81.5 years (59-94) at the time of fracture. Thirty-three patients were women, and 22 fractures were on the left side. Without exception, locking plates were used. The 1-year mortality rate for the sample was 27.5% (n = 11). Three revisions (7.5%) were performed for plate breakage. Rate of infection and non-union was zero. Three different fracture patterns were assessed: (1) transverse or oblique fractures below the tip of the stem (n = 9); (2) spiral-shaped fractures within the diaphysis (n = 19); and (3) burst fractures at the supracondylar region (n = 12). Demographic or outcome effects between fracture patterns were not found. On average of 4.2 years (2.0-10.4) after treatment, the mean reported Parker score was 5.5 (1-9). CONCLUSION: ORIF with a single lateral locking plate is safe for type Vancouver C fractures with a well-fixed hip stem. Therefore, we do not recommend routinely revision arthroplasty or orthogonal double plating. Three subtypes of fractures within Vancouver C demonstrated no significant differences in baseline data and outcome.

Supercurrent diode effect and magnetochiral anisotropy in few-layer NbSe2.

Nonreciprocal transport refers to charge transfer processes that are sensitive to the bias polarity. Until recently, nonreciprocal transport was studied only in dissipative systems, where the nonreciprocal quantity is the resistance. Recent experiments have, however, demonstrated nonreciprocal supercurrent leading to the observation of a supercurrent diode effect in Rashba superconductors. Here we report on a supercurrent diode effect in NbSe2 constrictions obtained by patterning NbSe2 flakes with both even and odd layer number. The observed rectification is a consequence of the valley-Zeeman spin-orbit interaction. We demonstrate a rectification efficiency as large as 60%, considerably larger than the efficiency of devices based on Rashba superconductors. In agreement with recent theory for superconducting transition metal dichalcogenides, we show that the effect is driven by the out-of-plane component of the magnetic field. Remarkably, we find that the effect becomes field-asymmetric in the presence of an additional in-plane field component transverse to the current direction. Supercurrent diodes offer a further degree of freedom in designing superconducting quantum electronics with the high degree of integrability offered by van der Waals materials.

Supercurrent and Phase Slips in a Ballistic Carbon Nanotube Bundle Embedded into a van der Waals Heterostructure.

We demonstrate long-range superconducting correlations in a several-micrometers-long carbon nanotube bundle encapsulated in a van der Waals stack between hBN and NbSe2. We show that a substantial supercurrent flows through the nanotube section beneath the NbSe2 crystal as well as through the 2 µm long section not in contact with it. The large in-plane critical magnetic field of this supercurrent is an indication that even inside the carbon nanotube Cooper pairs enjoy a degree of paramagnetic protection typical of the parent Ising superconductor. As expected for superconductors of nanoscopic cross section, the current-induced breakdown of superconductivity is characterized by resistance steps due to the nucleation of phase slip centers. All elements of our hybrid device are active building blocks of several recently proposed setups for realization of Majorana fermions in carbon nanotubes.

Narrow-band high-lying excitons with negative-mass electrons in monolayer WSe2.

Monolayer transition-metal dichalcogenides (TMDCs) show a wealth of exciton physics. Here, we report the existence of a new excitonic species, the high-lying exciton (HX), in single-layer WSe2 with an energy of ~3.4 eV, almost twice the band-edge A-exciton energy, with a linewidth as narrow as 5.8 meV. The HX is populated through momentum-selective optical excitation in the K-valleys and is identified in upconverted photoluminescence (UPL) in the UV spectral region. Strong electron-phonon coupling results in a cascaded phonon progression with equidistant peaks in the luminescence spectrum, resolvable to ninth order. Ab initio GW-BSE calculations with full electron-hole correlations explain HX formation and unmask the admixture of upper conduction-band states to this complex many-body excitation. These calculations suggest that the HX is comprised of electrons of negative mass. The coincidence of such high-lying excitonic species at around twice the energy of band-edge excitons rationalizes the excitonic quantum-interference phenomenon recently discovered in optical second-harmonic generation (SHG) and explains the efficient Auger-like annihilation of band-edge excitons.

Total Hip Arthroplasty for Hip Fractures: Time to Surgery With Respect to Surgical Revision, Failure, and Mortality.

INTRODUCTION: There are increasing demands to perform surgery of hip fractures without delay. However, few studies have assessed the time to surgery in relation to outcome measurements. METHODS: A total of 643 consecutive patients with a minimum age of 60 years underwent total hip arthroplasty (THA) for an intracapsular hip fracture. For this retrospective case series, demographic data and the outcome measurements-(1) any surgical revision, (2) implant failure, and (3) mortality-were documented from a prospective clinical database. The time from admission to surgery was also documented prospectively and then data were divided into 4 groups according to the time of surgery: (1) within 12 hours, (2) >12 to 24 hours, (3) >24 to 48 hours, and (4) later than >48 hours. The study end point was 2 years after surgery. Final evaluation was conducted for any missing data through a telephone interview. RESULTS: The patients comprised 456 women (70.9%) and 187 men (29.1%) with a mean age of 80.2 years (range 60-104 years; standard deviation ±7.4). Descriptive data were without effect in all 4 groups. Time to surgery did not significantly influence revision for any reason (P = .323), implant failure (P = .521), and mortality (P = .643). Cox regression analysis identified male sex (P < .001; 95% confidence interval (CI), 1.27-2.44), American Society of Anesthesiologists score ≥3 (P < .001; 95% CI, 2.12-21.59), C-reactive protein level >21 mg/L (P < .018; 95% CI, 1.09-2.60), hemoglobin level <12.0 g/dL (P = .033; 95% CI, 1.04-2.68), and dementia (P < .000; 95% CI, 1.50-2.86) as independent significant risk factors for mortality. CONCLUSION: Time to surgery had no effect on revision for any reason, implant failure, and mortality in patients undergoing THA for an intracapsular hip fracture.

Comparative analysis of non-simultaneous bilateral fractures of the proximal femur.

PURPOSE: We performed a monocenter cohort study to determine surgical revision and mortality after sustaining an initial and a non-simultaneous contralateral proximal femoral fracture. METHODS: We identified all patients surgically treated for a contralateral femoral fracture between 2006 and 2015. Patient demographic characteristics and follow-up were identified by our electronic database; failed information regarding revision and mortality were obtained by telephone, as well as the evaluation of the mobility for all alive patients. The endpoint of the study was set for every patient at least 2 years postoperatively. RESULTS: Within a total of 2296 patients, we identified 250 patients (10.8%) treated for a contralateral fracture. The mean interval between the two occurrences was 5.2 years and the mean age at the time of contralateral fracture was 84.4 years. Almost every third fracture occurred later than 5 years after the initial fracture, and even every tenth fracture later than 10 years. More than 50% of the patients also had dementia at this time. The total surgical revision rate was 17.2% after initial, and 20.4% after contralateral fracture, but this difference was statistically not significant (p = 0.31). However, revisions for infection or hematoma were more than twice after contralateral fracture (p = 0.006). The 1-year mortality rate was 36%, and dementia (log rank p < 0.001) and male gender (log rank p < 0.001) were significant negative predictors for the survival rate. After a mean of 42 months, the follow-up of the 67 alive patients recorded a mean Parker Score of 5.2 items. CONCLUSION: Contralateral femoral fracture was accompanied by a higher revision and mortality rate-but patients were also 5 years older. Dementia and male gender were significant negative variables for the survival time. In the future, the highest priority will be the prophylaxis of falling to avoid or at least to decline the number of these fractures in geriatric patients.

[Analysis of 2000 surgically treated proximal femoral fractures : Multiple variables influence mortality]. / Analyse von 2000 operativ versorgten proximalen Femurfrakturen : Multiple Variablen beeinflussen die Mortalität.

BACKGROUND: Due to demographic change, more proximal femoral fractures can be expected in the future. However, accurate growth rates as well as follow-up research extending more than 1 year postsurgery are still lacking. MATERIALS AND METHODS: First, we defined inclusion and exclusion criteria for the retrospective cohort study. Based on these, we collected all surgical interventions conducted between 1 January 2006 and 31 December 2015. For a total of 2000 consecutive procedures, we retrieved and analysed a total of 12 variables influencing mortality. Data were retrieved from the prospectively established database; all patients still alive were contacted by phone, and missing data were collected. The endpoint of the study was consistently set for all patients at 2 years postsurgery. RESULTS: The follow-up rate was 100%. Growth rate increased by 74.1% over a period of 10 years. Mean age of the total population was 79.4 years, and women were predominantly affected (71.7%). Surgical treatment was based on osteosynthesis procedures (57%) using DHS, PFN, or screws, as well as on arthroplasty (43%) performing total hip arthroplasty or implanting large-head prostheses. The revision rate was 14.5%, and mortality 2 years postsurgery was 32.4%. Through a multivariate analysis (Cox regression), the following seven influence factors showed statistically significant impact on mortality: age >82 years, male gender, CRP >10 mg/dl, haemoglobin <12 g/dl, ASA 3 or 4, dementia, and postoperative infection-but not timing of surgery. CONCLUSION: The growth rate of proximal femoral fractures progressed more rapidly than expected. Through a multivariate analysis, a total of six intrinsic variables were verified, which influenced the mortality. The prevention of infection-as the only additional extrinsic factor in this study-represents a more important role than early surgical treatment.

Total hip arthroplasty after failed osteosynthesis of proximal femoral fractures: Revision and mortality of 80 patients.

PURPOSE: Total hip arthroplasty (THA) after failed osteosynthesis for proximal femoral fractures is associated with higher revision rates, particularly for dislocation. The purpose of this study was to report our results with THA after failed osteosynthesis within a treatment period of 10 years. METHODS: A retrospective cohort study including 80 consecutive patients was conducted. After a minimum follow-up of 1 year, we evaluated revision for any cause including dislocation, outcome, and mortality. RESULTS: We performed 48 THAs with standard components only and 32 THAs with revision implants. Routinely, a 36-mm femoral head was used, and trochanteric fixation was performed in one-third of the cases. Total revision rate for any cause was 21%, which included six infections, six periprosthetic fractures, and five hematomas. One hip dislocation was also treated. Treatment with uncemented revision stem revealed significantly higher number of revisions-compared to standard cemented or uncemented stem. The mortality rate after 1 year was 9%, and the mean Parker score at follow-up was 6.6 (range: 0-9). CONCLUSIONS: THA was associated with an increased surgical revision rate, but hip dislocation was documented only once. In most cases, a standard implant with a large 36-mm femoral head size was sufficient. Uncemented revision stem revealed significantly higher number of revisions-compared to standard cemented or uncemented stem. One-year mortality was lower than expected.

The fate of proximal femoral fractures in the 10th decade of life: an analysis of 117 consecutive patients.

INTRODUCTION: To date, there is a lack of valid data with larger populations of patients in their 10th decade of life in the analyses of proximal femoral fractures. MATERIAL AND METHODS: The inclusion criteria focused on all proximal femoral fractures in patients 90-99 years of age who underwent surgical treatment between 2009 and 2012. After a period of at least 2 years post-surgery, a retrospective collection of empiric data, including the survival time and surgical revision rate, was performed. Missing data were collected per telephone interview. RESULTS: A total of 121 proximal femoral fractures in 117 patients in their 10th decade of life were treated. The mean age was 92.3 years. 61 fractures of the femoral neck received hemi- or total hip arthroplasty, while 60 pertrochanteric or subtrochanteric fractures were treated by osteosynthesis using proximal femoral nail (PFN) or dynamic hip screw (DHS). At the time of follow-up, 83/117 patients (71%) were already deceased. The mortality after 30 days, 6 months, 1 year and 2 years was 16%, 37%, and 43%, and 55%, respectively. A total of 22 surgical revisions (19%) were performed: 10 due to early infections, 8 due to haematomas, and 4 due to implant failures with a "cut out" of the femoral neck screw exclusively in DHS. The duration of surgery (with regard to surgical revision) and ASA classification (with regard to survival rate) were significant influence factors. Contralateral proximal femoral fractures were identified in 24/117 patients (20%), irrespective of study period. CONCLUSIONS: The proximal femoral fractures in the 10th decade of life are associated with high postoperative mortality within the first 6 months. Surgical revision due to complications did not result in a statistically significant reduction of the survival time. From the osteosynthetic perspective, the DHS was associated with a significantly higher "cut-out" rate compared to PFN procedure. With regard to the alloarthoplasty, there were no significant differences observed between hemi- and total hip arthroplasty. A contralateral femoral fractures was observed in 20% of the total study population, but peri-implant or periprosthetic femoral fractures have not been observed in any of the cases thus far.