Delay to Surgical Treatment in Geriatric Hip Fracture Patients.

Background: Hip fractures in the geriatric population are frequently encountered. There is increasing focus on minimizing the delay to surgery in these patients. This study was designed to evaluate factors responsible for a delay to surgery in a geriatric hip fracture population and how time to surgery affects mortality. Methods: A retrospective cohort of patients sustaining low energy geriatric hip fractures in either an American College of Surgeons (ACS) verified Level 1 trauma center or a local university affiliated community teaching hospital were reviewed. The following variables were evaluated as independent risk factors for delay to surgery: demographic data, surgical details, use of cardiology resources, treatment center, and comorbidities. As a secondary objective, the effect of time to surgery on 1 year mortality was analyzed. Results: 1157 patients met inclusion criteria. The following factors increased the risk of delay to surgery greater than 48 hours: male sex, treatment in a community hospital (versus trauma center), older age, multiple comorbidities (eg, cardiovascular-related conditions or other fractures), cardiology consultation, and an American Society of Anesthesiologists physical status score of 3 or 4. Cardiology consultation was the strongest independent predictor of risk for delay to surgery of >48 hours (odds ratio, 6.68; 95% confidence interval, 4.40 to 10.14; P < .001). The 1-year mortality of patients did not differ when surgical treatment occurred before 48 hours or after 48 hours (Log-rank test P = .109). Conclusion: The presence of cardiovascular comorbidities and cardiology consultations can delay surgical treatments for hip fractures in patients greater than 65 years old, but the delay did not influence 1-year all-cause mortality. Level of Evidence: Level IV.

Computed Tomography Measured Psoas Cross Sectional Area Is Associated With Bone Mineral Density Measured by Dual Energy X-Ray Absorptiometry.

Dual-energy X-ray absorptiometry (DEXA) is the gold standard for osteoporosis screening and diagnosis. However, abdominal conventional computed tomography (CT) scan is widely available and multiple studies validated its use as a screening tool for osteoporosis compared to DEXA. The aim of this study was to determine the reliability of measuring core muscle size at the L3-L4 intervertebral disk space and estimate the relationship between core muscle size and bone mineral density (BMD) measured by DEXA. Retrospective chart review was performed on patients who underwent a DEXA scan for osteoporosis and a conventional abdominal CT scan within one-year apart. Total cross-sectional area (CSA) and Hounsfield Unit (HU) density of core muscles (psoas, paraspinal, and abdominal wall muscles) were measured. The association between psoas, paraspinal, abdominal, and central muscle CSA and Bone Mineral density (BMD) at L3, L4, total Lumbar Spine (LS), and right (R) and left (L) hip was estimated in crude and adjusted for age and sex linear regression models. Sixty patients (37 females, 23 males) met the inclusion criteria. The average interval between DEXA and abdominal CT scans was 3.6 months (range 0.1-10.2). Psoas muscle density was significantly positively associated with R hip BMD in both crude and adjusted models (ß = 20.2, p = 0.03; ß = 18.5, p = 0.01). We found a significant positive linear association between psoas muscle CSA and HU density with BMD of LS, R, and L hip in both crude and adjusted models. The strongest significant positive linear association was observed between total abdominal CSA and R hip BMD in crude and age and sex adjusted (ß = 85.3, p = 0.01; ß = 63.9, p = 0.02, respectively). CT scans obtained for various clinical indications can provide valuable information regarding BMD. This is the first study investigating association between BMD with central muscle density and CSA, and it demonstrated their significant positive the association.

Data-driven RRAM device models using Kriging interpolation.

A two-tier Kriging interpolation approach is proposed to model jump tables for resistive switches. Originally developed for mining and geostatistics, its locality of the calculation makes this approach particularly powerful for modeling electronic devices with complex behavior landscape and switching noise, like RRAM. In this paper, a first Kriging model is used to model and predict the mean in the signal, followed up by a second Kriging step used to model the standard deviation of the switching noise. We use 36 synthetic datasets covering a broad range of different mean and standard deviation Gaussian distributions to test the validity of our approach. We also show the applicability to experimental data obtained from TiOx devices and compare the predicted vs. the experimental test distributions using Kolmogorov-Smirnov and maximum mean discrepancy tests. Our results show that the proposed Kriging approach can predict both the mean and standard deviation in the switching more accurately than typical binning model. Kriging-based jump tables can be used to realistically model the behavior of RRAM and other non-volatile analog device populations and the impact of the weight dispersion in neural network simulations.

Expansion of myeloid-derived suppressor cells contributes to metabolic osteoarthritis through subchondral bone remodeling.

BACKGROUND: Osteoarthritis (OA) subsequent to acute joint injury accounts for a significant proportion of all arthropathies. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of myeloid progenitor cells classically known for potent immune-suppressive activity; however, MDSCs can also differentiate into osteoclasts. In addition, this population is known to be expanded during metabolic disease. The objective of this study was to determine the role of MDSCs in the context of OA pathophysiology. METHODS: In this study, we examined the differentiation and functional capacity of MDSCs to become osteoclasts in vitro and in vivo using mouse models of OA and in MDSC quantitation in humans with OA pathology relative to obesity status. RESULTS: We observed that MDSCs are expanded in mice and humans during obesity. MDSCs were expanded in peripheral blood of OA subjects relative to body mass index and in mice fed a high-fat diet (HFD) compared to mice fed a low-fat diet (LFD). In mice, monocytic MDSC (M-MDSC) was expanded in diet-induced obesity (DIO) with a further expansion after destabilization of the medial meniscus (DMM) surgery to induce post-traumatic OA (PTOA) (compared to sham-operated controls). M-MDSCs from DIO mice had a greater capacity to form osteoclasts in culture with increased subchondral bone osteoclast number. In humans, we observed an expansion of M-MDSCs in peripheral blood and synovial fluid of obese subjects compared to lean subjects with OA. CONCLUSION: These data suggest that MDSCs are reprogrammed in metabolic disease, with the potential to contribute towards OA progression and severity.

Nonresonant Transmission Line Probe for Sensitive Interferometric Electron Spin Resonance Detection.

Electron spin resonance (ESR) spectroscopy measures paramagnetic free radicals, or electron spins, in a variety of biological, chemical, and physical systems. Detection of diverse paramagnetic species is important in applications ranging from quantum computation to biomedical research. Countless efforts have been made to improve the sensitivity of ESR detection. However, the improvement comes at the cost of experimental accessibility. Thus, most ESR spectrometers are limited to specific sample geometries and compositions. Here, we present a nonresonant transmission line ESR probe (microstrip geometry) that effectively couples high frequency microwave magnetic field into a wide range of sample geometries and compositions. The nonresonant transmission line probe maintains detection sensitivity while increasing availability to a wider range of applications. The high frequency magnetic field homogeneity is greatly increased by positioning the sample between the microstrip signal line and the ground plane. Sample interfacing occurs via a universal sample holder which is compatible with both solid and liquid samples. The unavoidable loss in sensitivity due to the nonresonant nature of the transmission line probe (low Q) is recuperated by using a highly sensitive microwave interferometer-based detection circuit. The combination of our sensitive interferometer and nonresonant transmission line provides similar sensitivity to a commercially available ESR spectrometer equipped with a high-Q resonator. The nonresonant probe allows for transmission, reflection, or dual-mode detection (transmission and reflection), where the dual-mode results in a √2 signal enhancement.

Slow- and rapid-scan frequency-swept electrically detected magnetic resonance of MOSFETs with a non-resonant microwave probe within a semiconductor wafer-probing station.

We report on a novel electron paramagnetic resonance (EPR) technique that merges electrically detected magnetic resonance (EDMR) with a conventional semiconductor wafer probing station. This union, which we refer to as wafer-level EDMR (WL-EDMR), allows EDMR measurements to be performed on an unaltered, fully processed semiconductor wafer. Our measurements replace the conventional EPR microwave cavity or resonator with a very small non-resonant near-field microwave probe. Bipolar amplification effect, spin dependent charge pumping, and spatially resolved EDMR are demonstrated on various planar 4H-silicon carbide metal-oxide-semiconductor field-effect transistor (4H-SiC MOSFET) structures. 4H-SiC is a wide bandgap semiconductor and the leading polytype for high-temperature and high-power MOSFET applications. These measurements are made via both "rapid scan" frequency-swept EDMR and "slow scan" frequency swept EDMR. The elimination of the resonance cavity and incorporation with a wafer probing station greatly simplifies the EDMR detection scheme and offers promise for widespread EDMR adoption in semiconductor reliability laboratories.

Decreased Lean Psoas Cross-Sectional Area Is Associated With Increased 1-Year All-Cause Mortality in Male Elderly Orthopaedic Trauma Patients.

OBJECTIVES: To investigate the association between lean psoas cross-sectional area (CSA) and 1-year all-cause mortality in elderly patients sustaining pelvic and long bone fractures. DESIGN: Retrospective cohort. SETTING: Level I trauma center. PATIENTS: Elderly trauma patients admitted from 2007 to 2014. METHODS: We reviewed demographic and clinical data, injury mechanism, fracture OTA/AO classification, and mortality. Axial computed tomography images were used to measure lean psoas CSA at the L3-L4 disk space. Cox proportional hazard regression analysis was used to estimate 1-year mortality association with psoas CSA in crude and adjusted for age, body mass index, Injury Severity Score, medical comorbidities, and discharge destination in total population and stratified by sex. MAIN OUTCOME MEASUREMENT: One-year all-cause mortality defined as death within 12 months from date of hospitalization. RESULTS: Five hundred fifty-eight patients (54% female, 46% male) were analyzed. The pelvis was most commonly fractured (37.81%). A statistically significant association was observed between decreased lean psoas CSA and 1-year mortality in total population {hazard ratio [HR] = 0.93 [95% confidence interval (CI) = 0.90-0.96], P < 0.0001}. Stratification by gender revealed a statistically significant mortality HR in male patients [HR = 0.89 (95% CI = 0.84-0.96), P = 0.002]. We did not find a statistically significant mortality HR in female patients [HR = 0.95 (95% CI = 0.89-1.01), P = 0.103]. CONCLUSIONS: In this cohort of elderly orthopaedic trauma patients, decreased lean psoas CSA was associated with increased 1-year all-cause mortality in total population and males. Further investigation of the association of sarcopenia with mortality in the elderly is warranted. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Wafer-Level Electrically Detected Magnetic Resonance: Magnetic Resonance in a Probing Station.

We report on a novel semiconductor reliability technique that incorporates an electrically detected magnetic resonance (EDMR) spectrometer within a conventional semiconductor wafer probing station. EDMR is an ultrasensitive electron paramagnetic resonance technique with the capability to provide detailed physical and chemical information about reliability limiting defects in semiconductor devices. EDMR measurements have generally required a complex apparatus, not typically found in solid-state electronics laboratories. The union of a semiconductor probing station with EDMR allows powerful analytical measurements to be performed within individual devices at the wafer level. Our novel approach replaces the standard magnetic resonance microwave cavity or resonator with a small non- resonant near field microwave probe. Using this new approach we have demonstrated bipolar amplification effect and spin dependent charge pumping in various SiC based MOSFET structures. Although our studies have been limited to SiC based devices, the approach will be widely applicable to other types of MOSFETs, bipolar junction transistors, and various memory devices. The replacement of the resonance cavity with the very small non- resonant microwave probe greatly simplifies the EDMR detection scheme and allows for the incorporation of this powerful tool with a wafer probing station. We believe this scheme offers great promise for widespread utilization of EDMR in semiconductor reliability laboratories.

Weight bearing cone beam CT scan versus gravity stress radiography for analysis of supination external rotation injuries of the ankle.

For AO 44-B2 ankle fractures of uncertain stability, the current diagnostic standard is to obtain a gravity stress radiograph, but some have advocated for the use of weight-bearing radiographs. The primary aim was to compare measures of medial clear space (MCS) on weight-bearing cone beam computed tomography (CBCT) scans versus gravity stress radiographs for determining the state of stability of ankle fractures classified as AO SER 44-B2 or Weber B. The secondary aim was to evaluate the details offered by CBCT scans with respect to other findings that may be relevant to patient care. Nine patients were enrolled in this cross-sectional study between April 2016 and February 2017 if they had an AO SER 44-B2 fracture of uncertain stability, had a gravity stress radiograph, and were able to undergo CT scan within seven days. The width of the MCS was measured at the level of the talar dome on all radiographs and at the mid coronal slice on CT. Wilcoxon signed-ranks tests were used to compare MCS between initial radiographs, gravity stress radiographs and weight-bearing CBCT scans. MCS on weight-bearing CBCT scan (1.41±0.41 mm) was significantly less than standard radiographs (3.28±1.63 mm, P=0.004) and gravity stress radiographs (5.82±1.93 mm, P=0.02). There was no statistically significant difference in MCS measured on standard radiographs versus gravity stress radiographs (P=0.11). Detailed review of the multiplanar CT images revealed less than perfect anatomical reduction of the fractures, with residual fibular shortening, posterior displacement, and fracture fragments in the incisura as typical findings. Similar to weight-bearing radiographs, weight-bearing CBCT scan can predict stability of AO 44-B2 ankle fractures by showing restoration of the MCS, and might be used to indicate patients for non-operative treatment. None of the fractures imaged in this study were perfectly reduced however, and further clinical research is necessary to determine if any of the detailed weight-bearing CBCT findings are related to patient outcomes.

Tibial Tubercle Fracture After Bone-Patellar Tendon-Bone Autograft.

Fractures occurring with anterior cruciate ligament (ACL) reconstruction are rare and those that do occur take place on the patellar side of a bone-patellar tendon-bone (BPTB) autograft. Here we discuss a far more infrequent occurrence, fracture of the tibial tubercle aspect of the BPTB autograft. This fracture type occurs even more infrequently than tibial plateau fractures after ACL reconstruction based on the published literature. In this article we discuss the third published episode of a tibial tubercle fracture after BPTB allograft. We also discuss the fracture types seen with this method of ACL reconstruction and provide insights into prevention of this occurrence.

Vectorized magnetometer for space applications using electrical readout of atomic scale defects in silicon carbide.

Magnetometers are essential for scientific investigation of planetary bodies and are therefore ubiquitous on missions in space. Fluxgate and optically pumped atomic gas based magnetometers are typically flown because of their proven performance, reliability, and ability to adhere to the strict requirements associated with space missions. However, their complexity, size, and cost prevent their applicability in smaller missions involving cubesats. Conventional solid-state based magnetometers pose a viable solution, though many are prone to radiation damage and plagued with temperature instabilities. In this work, we report on the development of a new self-calibrating, solid-state based magnetometer which measures magnetic field induced changes in current within a SiC pn junction caused by the interaction of external magnetic fields with the atomic scale defects intrinsic to the semiconductor. Unlike heritage designs, the magnetometer does not require inductive sensing elements, high frequency radio, and/or optical circuitry and can be made significantly more compact and lightweight, thus enabling missions leveraging swarms of cubesats capable of science returns not possible with a single large-scale satellite. Additionally, the robustness of the SiC semiconductor allows for operation in extreme conditions such as the hot Venusian surface and the high radiation environment of the Jovian system.

Geographic variation in fasciotomy during operative management of tibia fractures.

BACKGROUND: Diagnosis and treatment of acute or impending compartment syndrome (ACS) remains a clinical challenge. ACS is a clinical diagnosis, and may be associated with variation in its definition, as well as individual threshold for fasciotomy. We examined regional and state variation in rates of lower extremity fasciotomy associated with operatively managed tibia fractures. METHODS: A total of 313,344 surgically treated tibia fractures were identified via Current Procedural Terminology (CPT) codes using PearlDiver, a private-payer medical record database. Data from the PearlDiver database was compared to the National Trauma Data Bank trauma registry data to corroborate calculated fasciotomy rates. RESULTS: The aggregate United States fasciotomy rate derived from PearlDiver was 2.57%. State fasciotomy rates were wide-ranging (0.03%-11.86%) with an average state rate of 2.22% (n = 47, SD = 2.27). CONCLUSIONS: There was significant state-to-state variation in the use of fasciotomy during operative management of tibial fractures. Various factors may have contributed to the observed difference of state fasciotomy rates. LEVEL OF EVIDENCE: This is a Level III epidemiological study retrospectively comparing geographic rates of fasciotomy during operative management of tibia fractures.

Incidence and Injury Types in Motorcycle Collisions Involving Deer in Western New York.

Motorcycle popularity, urban sprawl, and large deer populations result in a significant number of deer-motorcycle collisions. This retrospective review of a level I trauma center in Buffalo, New York, revealed that 40 of 487 (8.2%) of patients admitted because of motorcycle crashes from May 2007 through June 2011 involved deer. There were 120 total injuries: the most common were orthopedic (39/120; 32.5%), chest (38/120; 31.7%), head (18/120; 15.0%), spine (10/120; 8.3%), facial (8/120; 6.7%), and abdominal (7/120; 5.8%). Thirty-five of 40 (87.5%) were men and were older (48.9 years, [SD, 8.9 years]) than the average for all motorcycle crashes during the study period (41.9 years, [SD, 13.9 years]). Mean (SD) injury severity score was 17.1 (9.8), reflecting the severity of encountered injuries. This study highlights the relatively common risk that deer pose to the motorcyclist and is comparable to published series in more rural Midwestern settings.

Comparison of fracture risk between patients with ileal pouch-anal anastomosis for ulcerative colitis and the general population.

BACKGROUND: Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the preferred surgical treatment for ulcerative colitis (UC). Little is known of how the operation affects bone metabolism and fracture risk. The aim of this retrospective cohort study was to investigate fracture risk and serum markers of bone metabolism following IPAA in a national cohort of Danish UC patients. METHODS: Diagnostic codes for 1757 patients and 8785 controls were obtained from the National Patient Register while blood results were collected from a regional database. Postoperative fracture free survival was evaluated on a Kaplan-Meier plot. Fracture hazard ratios (HR) after IPAA were calculated from Cox proportional hazards regression analysis. RESULTS: Fracture risk after IPAA was significantly reduced (adjusted HR = 0.49, 95% CI: 0.43; 0.55, p<0.001). Prior fractures and alcoholism independently increased fracture risk significantly. Osteoporotic fracture risk after IPAA was reduced, significantly for wrist fractures (aHR = 0.39, 95% CI: 0.22; 0.71, p = 0.002), and borderline insignificantly for spine fractures (aHR = 0.51, 95% CI: 0.26; 1.01, p = 0.054). Vitamin D and calcium levels were significantly higher in the patient group (61.2 nmol/L vs. 58.9 nmol/L, p = 0.04 and 1.24 mmol/L vs. 1.21 mmol/L, p<0.01, respectively), while parathyroid hormone and phosphate levels were significantly lower (4.9 pmol/L vs. 6.2 pmol/L, p<0.01 and 1.08 mmol/L vs. 1.12 mmol/L, p<0.01, respectively). CONCLUSION: Fracture risk after IPAA is significantly reduced compared to the general population. Prospective studies are needed to verify the biochemical results.

[No conclusive evidence for replacing conventional laparoscopic cholecystectomy with newer operating techniques]. / Ingen sikker evidens for at erstatte konventionel laparoskopisk kolecystektomi med nyere operationsteknikker.

Single-insicion laparoscopic surgery (SILS) and natural orifice transluminal endoscopic surgery (NOTES) represent the latest development in minimally invasive surgery and are used in a wide variety of operations, e.g. cholecystectomies. The proposed benefits are less surgical trauma, reduced post-operative pain, smaller risk of infection and hence a shortened hospital stay compared with conventional laparoscopy. So far, no randomised study has uniformly shown clear advantages of SILS or NOTES that could justify an implementation of these techniques as acceptable alternatives to conventional laparoscopy.

Donor site morbidity with reamer-irrigator-aspirator (RIA) use for autogenous bone graft harvesting in a single centre 204 case series.

Donor site morbidity and complication rate using the reamer-irrigator-aspirator (RIA) system for intramedullary, non-structural autogenous bone graft harvesting were investigated in a retrospective chart and radiographic review at a University affiliated Level-1 Trauma Centre. 204 RIA procedures in 184 patients were performed between 1/1/2007 and 12/31/2010. RIA-indication was bone graft harvesting in 201 (98.5%), and intramedullary irrigation and debridement in 3 (1.5%) cases. Donor sites were: femur - antegrade 175, retrograde 4, tibia - antegrade 7, retrograde 18. Sixteen patients had undergone two RIA procedures, two had undergone three procedures, all using different donor sites. In 4 cases, same bone harvesting was done twice. Mean volume of bone graft harvested was 47 ± 22ml (20-85 ml). The complication rate was 1.96% (N=4). Operative revisions included 2 retrograde femoral nails for supracondylar femur fractures 6 and 41 days postoperatively (antegrade femoral RIA), 1 trochanteric entry femoral nail (subtrochanteric fracture) 17 days postoperatively (retrograde femoral RIA) and 1 prophylactic stabilization with a trochanteric entry femoral nail for intraoperative posterior femoral cortex penetration without fracture. In our centre, the RIA technique has a low donor site morbidity and has been successfully implemented for harvesting large volumes of nonstructural autogenous bone graft.