Static Non-articulating Knee Spacers Are Associated with a High Degree of Morbidity in Challenging Clinical Scenarios.

The morbidity associated with the use of static non-articulating knee spacers for the treatment of periprosthetic joint infection (PJI) in challenging clinical scenarios has not been well described. From 2011-2019, 63 molded block static spacers were utilized at two academic institutions for the treatment of PJI with associated severe soft tissue compromise (59%), collateral ligament deficiency (49%), extensor mechanism compromise (48%), or type 3 bone defects (44%). Complications and outcomes were assessed. Complications with the use of static spacers were common and included further bone loss (46%), spacer migration (16%), extensor mechanism compromise (16%), cast or related soft tissue injuries (16%), fracture (13%), and spacer breakage (3%). Ultimately, 22% of patients underwent amputation. Patient variables such as age and body mass index were not associated with outcomes. Static knee spacers are associated with substantial morbidity in challenging clinical scenarios and alternatives may need to be considered. (Journal of Surgical Orthopaedic Advances 32(2):122-126, 2023).

Evaluation of a 30-day-mortality risk calculator for patients undergoing surgical fixation of fragility hip fractures.

INTRODUCTION: Hip fractures often occur in medically complex patients and can be associated with high perioperative mortality. Mortality risk assessment tools that are specific to hip fracture patients have not been extensively studied. The objective of this study is to evaluate a recently published 30-day mortality risk calculator (Hip Fracture Estimator of Mortality Amsterdam [HEMA]) in a group of patients treated at a university health system. MATERIALS & METHODS: 625 patients treated surgically for hip fractures between 2015 and 2020 at our institution were retrospectively reviewed. Patients younger than age 65, periprosthetic fractures, revision procedures, and fractures treated non-operatively were excluded. Univariate and multivariate analyses were used to determine significant relationships between variables and 30-day mortality after surgery. Additional patient-specific risk factors not included in the original risk calculator were also evaluated. RESULTS: The observed 30-day mortality was 5.6%. HEMA score was significantly associated with 30-mortality, though our cohort had significantly lower mortality rates in high-risk patients than expected based on the HEMA tool. In analyzing patient characteristics not included in HEMA score, history of dementia and elevated troponin were significantly associated with 30-day mortality. DISCUSSION: The HEMA score reliably stratifies risk for 30-day mortality after hip fracture, though overestimates mortality in high-risk patients treated at a tertiary care center with a multidisciplinary team. The HEMA score may be enhanced by considering additional variables, including troponin level and history of dementia. LEVEL OF EVIDENCE: IV.

Proximal tibia fracture dislocations: Management and outcomes of a severe and under-recognized injury.

INTRODUCTION: Proximal tibia fracture dislocations (PTFDs) are a subset of plateau fractures with little in the literature since description by Hohl (1967) and classification by Moore (1981). We sought to evaluate reliability in diagnosis of fracture-dislocations by traumatologists and to compare their outcomes with bicondylar tibial plateau fractures (BTPFs). METHODS: This was a retrospective cohort study at 14 level 1 trauma centers throughout North America. In all, 4771 proximal tibia fractures were reviewed by all sites and 278 possible PTFDs were identified using the Moore classification. These were reviewed by an adjudication board of three traumatologists to obtain consensus. Outcomes included inter-rater reliability of PTFD diagnosis, wound complications, malunion, range of motion (ROM), and knee pain limiting function. These were compared to BTPF data from a previous study. RESULTS: Of 278 submitted cases, 187 were deemed PTFDs representing 4% of all proximal tibia fractures reviewed and 67% of those submitted. Inter-rater agreement by the adjudication board was good (83%). Sixty-one PTFDs (33%) were unicondylar. Eleven (6%) had ligamentous repair and 72 (39%) had meniscal repair. Two required vascular repair. Infection was more common among PTFDs than BTPFs (14% vs 9%, p = 0.038). Malunion occurred in 25% of PTFDs. ROM was worse among PTFDs, although likely not clinically significant. Knee pain limited function at final follow-up in 24% of both cohorts. CONCLUSIONS: PTFDs represent 4% of proximal tibia fractures. They are often unicondylar and may go unrecognized. Malunion is common, and PTFD outcomes may be worse than bicondylar fractures.

National Evaluation of Social Determinants of Health in Orthopedic Fracture Care: Decreased Social Determinants of Health Is Associated With Increased Adverse Complications After Surgery.

OBJECTIVES: To assess the individual impact of social determinants of health disparities (SDHD) on surgical outcomes following orthopaedic trauma surgery. DESIGN: Retrospective Cohort Study. SETTING: Mariner Claims Database. PATIENTS: Inclusion criteria were patients 18-85 years of age, undergoing surgery for hip fractures or ankle fractures from 2010 to 2018. INTERVENTION: Patients were divided based on SDHD using International Classification of Diseases 9 and International Classification of Diseases 10 codes. Those with SDHD were propensity-score matched with those who did not have any disparities with respect to age, gender, Charlson comorbidity index, tobacco use, and obesity (body mass index >30 kg/m2). OUTCOMES: Ninety-day major medical complications, infection, readmission, and revisions within 1 year. RESULTS: Patients with educational deficiencies had increased rates of readmission and major complications compared with those without disparities following hip and ankle fracture management. Moreover, economic disparities were associated with an increased risk of readmission and revision following hip fracture surgery and infection and readmission following ankle fracture surgery. DISCUSSION/CONCLUSIONS: This study emphasizes the large impact of SDHD on patients' outcomes following surgery and the importance of proper follow-up interventions to optimize patient care. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ca2+/calmodulin-dependent protein kinase II and Dimethyl Sulfoxide affect the sealing frequencies of transected hippocampal neurons.

Traumatic injury often results in axonal severance, initiating obligatory Wallerian degeneration of distal segments, whereas proximal segments often survive. Calcium ion (Ca2+ ) influx at severed proximal axonal ends activates pathways that can induce apoptosis. However, this same Ca2+ -influx also activates multiple parallel pathways that seal the plasmalemma by inducing accumulation and fusion of vesicles at the lesion site that reduce Ca2+ -influx and enhance survival. We examined whether various inhibitors of Ca2+ /calmodulin-dependent protein kinases (CaMKs), and/or dimethyl sulfoxide (DMSO), a common solvent for biologically active substances, affected the ability of a hippocampal-derived neuronal cell line (B104 cells) to seal membrane damage following axotomy. Axolemmal sealing frequencies were assessed at different transection distances from the axon hillock and at various times after Ca2+ -influx (PC times) by observing whether transected cells took-up fluorescent dyes. Inhibition of CaMKII by tatCN21 and KN-93, but not inhibition of CaMKI and CaMKIV by STO-609, affected axonal sealing frequencies. That is, CaMKII is a component of previously reported parallel pathways that induce membrane sealing, whereas CaMKI and CaMKIV are not involved. The effects of these CaMKII inhibitors on plasmalemmal sealing depended on their mechanism of inhibition, transection distance, and PC time. DMSO at low concentrations (90 µM-28 mM or 0.00064%-0.2% v/v) significantly increased membrane-sealing frequencies at most PC times and transection distances, possibly by permeabilizing the plasmalemma to Ca2+ . Inhibition of CaMKII, DMSO, PC time, and the transection distance significantly affect plasmalemmal sealing that is critical to somal survival in traumatic lesions.

Immune markers of social cognitive bias in schizophrenia.

Social cognition is impaired in schizophrenia, is relatively independent of purely neurocognitive domains such as attention and executive functioning, and may be the strongest predictor of functional outcome in this disease. Within a motivated reasoning framework, we tested the hypothesis that the anti-inflammatory Th2-associated cytokines, IL-10 and MDC, would be correlated with behavioral measures of social cognitive threat-detection bias (self-referential gaze detection bias and theory of mind (ToM) bias) in delusional versus non-delusional patients. We administered to schizophrenia patients with delusions (n=21), non-delusional patients (n=39) and controls (n=20) a social cognitive task designed to be sensitive to psychosocial stress response (the Waiting Room Task) and collected plasma levels of inflammatory markers using a bead-based flow immunoassay. Results partially supported our hypothesis. The anti-inflammatory cytokine IL-10 was associated with self-referential ToM bias in the delusional cohort as predicted, and not with non-delusional patients or healthy controls. This bias reflects a documented tendency of schizophrenia patients with delusions to excessively attribute hostile intentions to people in their environment. Since this cytokine correlated only with ToM bias and only in delusional patients, elevated levels of this cytokine in the blood may eventually serve as a useful biomarker distinguishing delusional patients from both non-delusional patients and healthy controls.

Effects of extracellular calcium and surgical techniques on restoration of axonal continuity by polyethylene glycol fusion following complete cut or crush severance of rat sciatic nerves.

Complete crush or cut severance of sciatic nerve axons in rats and other mammals produces immediate loss of axonal continuity. Loss of locomotor functions subserved by those axons is restored only after months, if ever, by outgrowths regenerating at ∼1 mm/day from the proximal stumps of severed axonal segments. The distal stump of a severed axon typically begins to degenerate in 1-3 days. We recently developed a polyethylene glycol (PEG) fusion technology, consisting of sequential exposure of severed axonal ends to hypotonic Ca(2+) -free saline, methylene blue, PEG in distilled water, and finally Ca(2+) -containing isotonic saline. This study examines factors that affect the PEG fusion restoration of axonal continuity within minutes, as measured by conduction of action potentials and diffusion of an intracellular fluorescent dye across the lesion site of rat sciatic nerves completely cut or crush severed in the midthigh. Also examined are factors that affect the longer-term PEG fusion restoration of lost behavioral functions within days to weeks, as measured by the sciatic functional index. We report that exposure of cut-severed axonal ends to Ca(2+) -containing saline prior to PEG fusion and stretch/tension of proximal or distal axonal segments of cut-severed axons decrease PEG fusion success. Conversely, trimming cut-severed ends in Ca(2+) -free saline just prior to PEG fusion increases PEG fusion success. PEG fusion prevents or retards the Wallerian degeneration of cut-severed axons, as assessed by measures of axon diameter and G ratio. PEG fusion may produce a paradigm shift in the treatment of peripheral nerve injuries. © 2016 Wiley Periodicals, Inc.

Nanosecond white-light Laue diffraction measurements of dislocation microstructure in shock-compressed single-crystal copper.

Under uniaxial high-stress shock compression it is believed that crystalline materials undergo complex, rapid, micro-structural changes to relieve the large applied shear stresses. Diagnosing the underlying mechanisms involved remains a significant challenge in the field of shock physics, and is critical for furthering our understanding of the fundamental lattice-level physics, and for the validation of multi-scale models of shock compression. Here we employ white-light X-ray Laue diffraction on a nanosecond timescale to make the first in situ observations of the stress relaxation mechanism in a laser-shocked crystal. The measurements were made on single-crystal copper, shocked along the [001] axis to peak stresses of order 50 GPa. The results demonstrate the presence of stress-dependent lattice rotations along specific crystallographic directions. The orientation of the rotations suggests that there is double slip on conjugate systems. In this model, the rotation magnitudes are consistent with defect densities of order 10(12) cm(-2).

Respiratory care year in review 2011: long-term oxygen therapy, pulmonary rehabilitation, airway management, acute lung injury, education, and management.

For the busy clinician, educator, or manager, it is becoming an increasing challenge to filter the literature to what is relevant to one's practice and then update one's practice based on the current evidence. The purpose of this paper is to review the recent literature related to long-term oxygen therapy, pulmonary rehabilitation, airway management, acute lung injury and acute respiratory distress syndrome, respiratory care education, and respiratory care management. These topics were chosen and reviewed in a manner that is most likely to have interest to the readers of Respiratory Care.

Milk processed by pulsed electric fields: evaluation of microbial quality, physicochemical characteristics, and selected nutrients at different storage conditions.

UNLABELLED: Pulsed electric fields (PEF) technology was used to pasteurize raw milk under selected treatments. Processing conditions were: temperature 20, 30, and 40 °C, electric field 30.76 to 53.84 kV/cm, and pulse numbers 12, 24, and 30 for skim milk (SM), and 12, 21, and 30 for whole milk (WM) (2 µs pulse width, monopolar). Physicochemical parameters (pH, electrical conductivity, density, color, solids nonfat [SNF]) and composition (protein and fat content) were measured after processing. Shelf life of SM and WM was assessed after processing at 46.15 kV/cm, combined with temperature (20 to 60 °C) and 30 pulses. Mesophilic and psychrophilic loads and pH were evaluated during storage at 4 and 21 °C. Results showed minor variations in physicochemical properties after processing. There was an interesting trend in SM in SNF, which decreased as treatment became stronger; similar behavior was observed for fat and protein, showing a 0.18% and 0.17% decrease, respectively, under the strongest conditions. Protein and fat content decreased in WM samples treated at 40 °C, showing a decrease in protein (0.11%), and an even higher decrease in fat content. During storage, PEF-treated milk samples showed higher stability at 4 °C with minor variations in pH; after 33 d, pH was higher than 6. However samples at 21 °C showed faster spoilage and pH dropped to 4 after 5 d. Growth of mesophilic bacteria was delayed in both milks after PEF processing, showing a 6- and 7-log cycles for SM and WM, respectively, after day 25 (4 °C); however, psychrophilic bacteria grew faster in both cases. PRACTICAL APPLICATION: Pulsed electric fields (PEF) technology in the pasteurization of liquid food products has shown positive results. Processing times can be reduced considerably, which in turn reduces the loss of nutrients and offers important savings in energy. PEF has been used successfully to pasteurize some liquid foods, but it is still not used commercially in milk pasteurization, although several trials have shown the positive effects of PEF milk pasteurization, which could allow for its future use at the industrial level.

The clinical impact of new long-term oxygen therapy technology.

Long-term oxygen therapy (LTOT) improves survival for patients afflicted with severe chronic obstructive pulmonary disease and may also reduce the incidence of repeat hospitalization due to exacerbations. When properly dosed and titrated, LTOT has also been shown to improve exercise tolerance, thereby enhancing the overall health-related quality of life for this growing patient population. Equipment used to provide LTOT is undergoing a radical transformation, with newer delivery devices offering a sharp contrast to older, more traditional home oxygen equipment. This newer approach to providing LTOT-commonly referred to as "non-delivery technology"-affords LTOT users unprecedented freedom, since they are no longer dependent on home-care providers for repeat deliveries to replenish or replace depleted oxygen contents. Instead, non-delivery LTOT equipment is self-sufficient and able to provide all of the oxygen needed to meet both stationary and ambulatory requirements. However, several models of the newer LTOT equipment have certain operational and performance limitations. Accordingly, in order to preclude unintended desaturation with newer LTOT devices, each patient must undergo an individualized pulse-oximetry titration study by a knowledgeable and experienced respiratory therapist to ensure optimum dosing under all conditions of use.

Effect of oxygen-absorbing packaging on the shelf life of a liquid-based component of military operational rations.

Oxygen within the sealed package can reduce the quality of liquid-based food products with high oil content such as hot-filled meal-ready-to-eat (MRE) cheese spread, a component of military operational rations. The aim of this study was to test a novel oxygen absorber-containing laminate material and its ability to maintain and/or extend shelf life of a cheese-spread MRE item. An iron-based oxygen absorber (ABSO(2)RB(R)) activated by moisture was incorporated into the laminate and used to pack hot-filled cheese spread MREs. The kinetics of oxygen absorption due to humidity and temperature were characterized and peel tests performed to ensure pouch seal integrity. Accelerated shelf-life tests of ABSO(2)RB and regular MRE pouches without the O(2)-absorber were conducted for 3 mo at 51.7 degrees C (125 degrees F), and 6 mo at 37.8 degrees C (100 degrees F) by measuring oxygen concentration (Mocon O(2)-analyzer), microbiological, and physicochemical quality characteristics, including color, texture, moisture, free fatty acid (FFA), pH, water activity, and vitamins and A. Pouches stored at 26.7 degrees C (80 degrees F) for 12 mo served as calibrated controls. Consumer tests were conducted in-house and a confirmatory sensory test was conducted at Natick by a trained panel using a 9-point hedonic scale. ABSO(2)RB-laminates maintain the same seal integrity and strength as those of the control samples. The headspace oxygen concentrations in these pouches reached (P < 0.05) < 0.5% in 11 d of storage at 26.7 degrees C (80 degrees F) and remained below this level throughout the storage period (1 y). No microbial growth (aerobic, coliforms, yeast, and molds) was detected (P < 0.05) for both packages. Overall, the ABSO(2)RB-pouches indicate an improved reduction in oxygen and vitamin C retention compared with MRE controls and maintained product quality (physicochemical and organoleptic). ABSO(2)RB-laminates met the accelerated shelf-life requirement of 1 mo at 51.7 degrees C (125 degrees F), and 6 mo at 37.8 degrees C (100 degrees F). This study clearly shows the benefits of using active packaging technology on retaining nutrition and prolonging shelf life of high-fat, liquid content MRE items.

Enhancement of extra chromosomal recombination in somatic cells by affecting the ratio of homologous recombination (HR) to non-homologous end joining (NHEJ).

Advancements in somatic cell gene targeting have been slow due to the finite lifespan of somatic cells and the overall inefficiency of homologous recombination. The rate of homologous recombination is determined by mechanisms of DNA repair, and by the balance between homologous recombination (HR) and non-homologous end joining (NHEJ). A plasmid-to-plasmid, extra chromosomal recombination system was used to study the effects of the manipulation of molecules involved in NHEJ (Mre11, Ku70/80, and p53) on HR/NHEJ ratios. In addition, the effect of telomerase expression, cell synchrony, and DNA nuclear delivery was examined. While a mutant Mre11 and an anti-Ku aptamer did not significantly affect the rate of NHEJ or HR, transient expression of a p53 mutant increased overall HR/NHEJ by 2.5 fold. However, expression of the mutant p53 resulted in increased aneuploidy of the cultured cells. Additionally, we found no relationship between telomerase expression and changes in HR/NHEJ. In contrast, cell synchrony by thymidine incorporation did not induce chromosomal abnormalities, and increased the ratio of HR/NHEJ 5-fold by reducing the overall rate of NHEJ. Overall our results show that attempts at reducing NHEJ by use of Mre11 or anti-Ku aptamers were unsuccessful. Cell synchrony via thymidine incorporation, however, does increase the ratio of HR/NHEJ and this indicates that this approach may be of use to facilitate targeting in somatic cells by reducing the numbers of colonies that need to be analyzed before a HR is identified.

Economic aspects of introducing new nebulizer technology.

The adoption of new medical technology has been a major factor in the development of today's highly sophisticated health care delivery system. Recently, important breakthroughs in biotechnology have introduced the possibility that certain terminal diseases may soon become a thing of the past. However, these advances have come at a steep price. Total health care spending in the United States is at an all-time high and the rate of increase in annual expenditures is once again in the double-digit neighborhood. It is clear that it will no longer be "business as usual" in health care, especially with regard to the introduction of new technology. New economic realities now require that those advocating the adoption of a new drug, device, or treatment balance their clinical enthusiasm with cost-effectiveness considerations. This is especially important when the cost of a new drug or device is higher than that of existing drugs or devices. Unlike former times, when the decision to adopt new medical technology resided primarily with clinicians, the approval process is now exceedingly more complex and involves many more individuals, some of whom, clinicians and non-clinicians alike, tend to focus more on protecting their budgets than on approving expenditures for new technology. Pharmacoeconomics has emerged to formalize the decision-making process for the adoption of new drugs. Since many of the issues are similar, the basic principles of pharmacoeconomics hold promise for physicians and therapists championing the adoption of new nebulizers. Pharmacoeconomic data, when gathered, reviewed, and presented in a standardized and unbiased manner, can be a valuable tool to help justify the overall cost/benefit advantages of new nebulizer technology.