Trends and epidemiology of lower trunk fractures in the super elderly population in the United States from 2011 to 2020.

INTRODUCTION: Fractures of the lower trunk are among the most common fractures occurring in the elderly. Super elderly individuals (i.e., those 80 years of age and older) represent a growing segment of the population and are especially prone to these fractures. The contemporary epidemiology of lower trunk fractures in the super elderly population is incompletely described in the literature. MATERIALS AND METHODS: This descriptive epidemiology study used the National Electronic Injury Surveillance System (NEISS) to examine the incidence and recent trends of lower trunk fractures (i.e., fractures of the hip, pelvis, and lumbar spine) occurring among super elderly individuals in the United States (US) from 2011 to 2020. Annual, overall, and age-/sex-specific incidence rates (IRs) were analyzed. Average annual percent change (AAPC) estimates were calculated to indicate the magnitude/direction of trends in annual injury rates. RESULTS: An estimated N=1,226,160 super elderly patients sustained lower trunk fractures over the 10-year study period for an overall IR of 100.2 per 10,000 person-years at-risk (PYR). Hip fractures accounted for the largest percentage of cases (IR=71.7 PYR), followed by lumbar spine fractures (IR=14.7), and pelvic fractures (IR=14.3). The incidence of lower trunk fractures among super elderly females (IR=121.5 PYR) was significantly greater than that of males (IR=65.7 PYR). The incidence of lower trunk fractures among nonagenarians and centenarians was significantly higher than that of octogenarians. Accounting for population growth yielded a significantly increasing annual incidence of lower trunk fractures in super elderly patients over the study period from 86.7 PYR in 2011 to 107.2 PYR in 2020 (AAPC=2.7, p<0.001). The annual incidence of both pelvic (AAPC=5.8) and lumbar spine (AAPC=6.9) fractures increased at a significantly higher rate than that of hip fractures (AAPC=1.4). CONCLUSIONS: This study suggests that the annual incidence of lower trunk fractures in the oldest cohort of patients in the US (80+ years of age) increased significantly during the recent decade from 2011 to 2020, with pelvic and lumbar fractures in particular becoming increasingly common. Increased incidence rates highlight the need for future research aimed at optimizing outcomes and quality of life in this frail and ever-growing segment of the population.

Why does one trust? A 360-degree perspective on the role of position power in weighting trustworthiness factors.

The purpose of the current paper is to explore the influence of the perceived trustworthiness factors of ability, benevolence and integrity on general and specific trust across supervisors, subordinates and peers with the same focal referent. This study used a 360-degree approach to examine how positional power asymmetries influence the relationship between trustworthiness and trust for a general and situation-specific referent. Data were obtained from military supervisors (N = 200), peers (N = 123), and subordinates (N = 85). Measures of trustworthiness and trust of a common military officer were obtained. Supervisors and subordinates differed in their relative weighting of trustworthiness factors (i.e. ability, benevolence, and integrity) when evaluating general and specific trust. Peers evidenced no difference in the relative weighting of trustworthiness factors. The relationship between benevolence and specific trust was stronger for subordinates than for supervisors. One implication of our findings is that trust can develop differently in bottom-up versus top-down organizational relationships. This study provides evidence that supervisors and subordinates emphasize different aspects of trustworthiness when evaluating their trust of a focal officer, and this process was different for general versus specific trust referents. The study also extends previous research by replicating previous findings across raters.

Poly(Sitosterol)-Based Hydrophobic Blocks in Amphiphilic Block Copolymers for the Assembly of Hybrid Vesicles.

Amphiphilic block copolymer and lipids can be assembled into hybrid vesicles (HVs), which are an alternative to liposomes and polymersomes. Block copolymers that have either poly(sitostryl methacrylate) or statistical copolymers of sitosteryl methacrylate and butyl methacrylate as the hydrophobic part and a poly(carboxyethyl acrylate) hydrophilic segment are synthesized and characterized. These block copolymers assemble into small HVs with soybean L-α-phosphatidylcholine (soyPC), confirmed by electron microscopy and small-angle X-ray scattering. The membrane's hybrid nature is illustrated by fluorescence resonance energy transfer between labeled building blocks. The membrane packing, derived from spectra when using Laurdan as an environmentally sensitive fluorescent probe, is comparable between small HVs and the corresponding liposomes with molecular sitosterol, although the former show indications of transmembrane asymmetry. Giant HVs with homogenous distribution of the block copolymers and soyPC in their membranes are assembled using the electroformation method. The lateral diffusion of both building blocks is slowed down in giant HVs with higher block copolymer content, but their permeability toward (6)-carboxy-X-rhodamine is higher compared to giant vesicles made of soyPC and molecular sitosterol. This fundamental effort contributes to the rapidly expanding understanding of the integration of natural membrane constituents with designed synthetic compounds to form hybrid membranes.

A Mechanistic and Preclinical Assessment of BioRestore Bioactive Glass as a Synthetic Bone Graft Extender and Substitute for Osteoinduction and Spine Fusion.

STUDY DESIGN: Preclinical animal study. OBJECTIVE: Evaluate the osteoinductivity and bone regenerative capacity of BioRestore bioactive glass. SUMMARY OF BACKGROUND DATA: BioRestore is a Food and Drug Administration (FDA)-approved bone void filler that has not yet been evaluated as a bone graft extender or substitute for spine fusion. METHODS: In vitro and in vivo methods were used to compare BioRestore with other biomaterials for the capacity to promote osteodifferentiation and spinal fusion. The materials evaluated (1) absorbable collagen sponge (ACS), (2) allograft, (3) BioRestore, (4) Human Demineralized Bone Matrix (DBM), and (5) MasterGraft. For in vitro studies, rat bone marrow-derived stem cells (BMSC) were cultured on the materials in either standard or osteogenic media (SM, OM), followed by quantification of osteogenic marker genes ( Runx2, Osx, Alpl, Bglap, Spp1 ) and alkaline phosphatase (ALP) activity. Sixty female Fischer rats underwent L4-5 posterolateral fusion (PLF) with placement of 1 of 5 implants: (1) ICBG from syngeneic rats; (2) ICBG+BioRestore; (3) BioRestore alone; (4) ICBG+Allograft; or (5) ICBG+MasterGraft. Spines were harvested 8 weeks postoperatively and evaluated for bone formation and fusion via radiography, blinded manual palpation, microCT, and histology. RESULTS: After culture for 1 week, BioRestore promoted similar expression levels of Runx2 and Osx to cells grown on DBM. At the 2-week timepoint, the relative ALP activity for BioRestore-OM was significantly higher ( P <0.001) than that of ACS-OM and DBM-OM ( P <0.01) and statistically equivalent to cells grown on allograft-OM. In vivo, radiographic and microCT evaluation showed some degree of bridging bone formation in all groups tested, with the exception of BioRestore alone, which did not produce successful fusions. CONCLUSIONS: This study demonstrates the capacity of BioRestore to promote osteoinductivity in vitro. In vivo, BioRestore performed similarly to commercially available bone graft extender materials but was incapable of producing fusion as a bone graft substitute. LEVEL OF EVIDENCE: Level V.

Activation and substrate specificity of the human P4-ATPase ATP8B1.

Asymmetric distribution of phospholipids in eukaryotic membranes is essential for cell integrity, signaling pathways, and vesicular trafficking. P4-ATPases, also known as flippases, participate in creating and maintaining this asymmetry through active transport of phospholipids from the exoplasmic to the cytosolic leaflet. Here, we present a total of nine cryo-electron microscopy structures of the human flippase ATP8B1-CDC50A complex at 2.4 to 3.1 Å overall resolution, along with functional and computational studies, addressing the autophosphorylation steps from ATP, substrate recognition and occlusion, as well as a phosphoinositide binding site. We find that the P4-ATPase transport site is occupied by water upon phosphorylation from ATP. Additionally, we identify two different autoinhibited states, a closed and an outward-open conformation. Furthermore, we identify and characterize the PI(3,4,5)P3 binding site of ATP8B1 in an electropositive pocket between transmembrane segments 5, 7, 8, and 10. Our study also highlights the structural basis of a broad lipid specificity of ATP8B1 and adds phosphatidylinositol as a transport substrate for ATP8B1. We report a critical role of the sn-2 ester bond of glycerophospholipids in substrate recognition by ATP8B1 through conserved S403. These findings provide fundamental insights into ATP8B1 catalytic cycle and regulation, and substrate recognition in P4-ATPases.

Epidemiology of C2 fractures in the United States: A National Electronic Injury Surveillance System database study.

Introduction: C2 fractures are one of the most common traumatic injuries of the cervical spine, with high rates of morbidity and mortality. Current literature on the incidence of C2 fractures is limited to populations outside of the United States (US), prior to 2014, or specific age cohorts. The purpose of this study is to report the incidence rate (IR) of C2 fractures and associated patient demographics in the US between 2002 and 2021 using the National Electronic Injury Surveillance System (NEISS) database. Methods: This study analyzed the NEISS database to identify cases of C2 fractures presenting to US Emergency Departments (EDs) from 2002 to 2021. Annual and overall numbers of fractures, IR, and patient demographics were analyzed. IR is expressed as the number of fractures per 100,000 person-years at risk (PYR). Patients were split into three different age groups for comparison (children and young adults, 0-64 years; older adults, 65-79 years; elderly individuals, 80 + years). Results: A national estimate of n = 72,764 patients (95% confidence interval [CI] = 54,371-91,156) presented to US EDs with a C2 fracture (IR was 1.17/PYR; 95% CI = 0.87-1.46), and elderly individuals had the highest IR overall (IR = 15.9; P < 0.05). The IR of C2 fractures between 2002 and 2021, reported as average annual percent change (AAPC), increased significantly, regardless of age or sex (AAPC = 10.9; 95% CI = 6.3-15.6; P < 0.0001). Conclusion: C2 fractures occur at higher rates than previous years, with especially high IR in elderly individuals. Emphasis of public health efforts toward osteoporosis and coordination difficulties in elderly individuals would likely significantly reduce the overall IR of these injuries.

Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons, emergency medicine physicians, and general surgeons in the United States.

BACKGROUND: Few contemporary studies have assessed physicians' knowledge of radiation exposure associated with common imaging studies, especially in trauma care. The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal (MSK) imaging studies routinely utilized in the trauma setting. METHODS: An electronic survey was distributed to United States orthopaedic surgery, general surgery, and emergency medicine (EM) residency programs. Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis, lumbar spine, and lower extremity, in terms of chest X-ray (CXR) equivalents. Physician estimates were compared to the true effective radiation doses. Additionally, participants were asked to report the frequency of discussing radiation risk with patients. RESULTS: A total of 218 physicians completed the survey; 102 (46.8%) were EM physicians, 88 (40.4%) were orthopaedic surgeons, and 28 (12.8%) were general surgeons. Physicians underestimated the effective radiation doses of nearly all imaging modalities, most notably for pelvic computed tomaography (CT) (median 50 CXR estimation vs. 162 CXR actual) and lumbar CT (median 50 CXR estimation vs. 638 CXR actual). There was no difference between physician specialties regarding estimation accuracy (P=0.133). Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure (P=0.007). CONCLUSION: The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking. Further investigation with larger scale studies is warranted, and additional education in this area may improve care.

Funding has no effect on studies evaluating viscosupplementation for knee osteoarthritis: A systematic review of bibliometrics and conflicts of interest.

Background: Viscosupplementation for knee osteoarthritis (OA) may raise concerns regarding conflicts of interest (COI). Evidence of inconclusive study results and publication bias in previous studies has led to concern that financial COI have influenced viscosupplementation outcomes. It is critical to ensure that clinical practice is guided by informed decision making and evidence-based medicine. Methods: A systematic review was conducted following PRISMA guidelines. PubMed, MEDLINE, and Web of Science databases were searched for articles pertaining to hyaluronic acid (or similarly derived) injections to native knees with primary OA only. Bibliometric data, financial COI, and study outcomes were assessed. Results: 67 studies met inclusion criteria for analysis, 53 of which (79.1%) presented Level I evidence, and 21 of which (31.3%) reported at least one author with COI. All studies reporting COI also disclosed industry funding. There were no relationships between reported COI and study outcomes (Χ 2  = 0.31, P = 0.577), levels of evidence (Χ 2  = 3.48, P = 0.176), or relative citation ratio (RCR) (S = 743, P = 0.591). Studies reporting COIs/industry funding tended to be published in journals with significantly higher impact factors (IF) (reporting COI: IF = 3.5 ± 2.0; no COI: IF = 1.8 ± 1.1; S = 950, P < 0.001). Study outcomes were not related to the probability of being published in an open access journal (Χ 2  = 0.01, P = 0.960), nor to level of evidence (Χ 2  = 2.67, P = 0.263), RCR (S = 618, P = 0.835), or IF (S = 563, P = 0.655). Conclusions: Investigator COIs (and commercial funding of studies) have not significantly influenced the frequency of favorable outcomes or study level of evidence regarding contemporary viscosupplementation for the treatment of knee OA. Studies reporting COIs/industry funding tended to be published in journals with significantly higher impact factors. Results overwhelmingly supported using viscosupplementation to treat knee OA. Level of evidence: Level V Systematic Review.

Trends and epidemiology of knee extensor mechanism injuries presenting to United States emergency departments from 2001 to 2020.

OBJECTIVES: Injuries to the native extensor mechanism (EM) of the knee are potentially disabling and often require surgical treatment. Large-scale, updated epidemiological data on these injuries is lacking. The objective of the current study was to examine recent trends in EM injuries presenting to United States (US) Emergency Departments (EDs) over the last 20 years using a nationally representative sample. METHODS: This study retrospectively analyzed the National Electronic Injury Surveillance System (NEISS) database to identify cases of EM injuries (defined as either a quadriceps tendon rupture, a patella fracture, or a patellar tendon rupture) presenting to EDs in the US from 2001 to 2020. RESULTS: During the study period, an estimated 214,817 EM injuries occurred in an at-risk population of 6,183,899,410 person-years for an overall incidence rate of 3.47 per 100,000 person-years. Patella fractures (PFs) were the most common injury type, representing 77.5% of all EM injuries (overall incidence rate: 2.69), followed by patellar tendon ruptures (PTRs; 13.5%; incidence: 0.48) and quadriceps tendon ruptures (QTRs; 9%; incidence: 0.31). Demographic characteristics and mechanisms of injury differed between injury types. Annual incidence rates increased significantly during the study period for all EM injury types, with PTRs demonstrating the largest relative increase (average annual percent increase: PF, 2.8%; PTR, 7.2%; QTR, 5.3%). Accounting for population growth yielded an increasing incidence of all EM injuries combined from 3.65 in 2001 to 4.9 in 2020. The largest relative increases in incidence rates were observed in older age groups. CONCLUSION: Extensor mechanism injuries of the knee are increasing in the US, which likely reflects an aging and more active population. These types of injuries are associated with substantial functional impairment and recent increases in incidence rates highlight the need for injury prevention and management strategies.

Accuracy of self-reported opioid use in orthopaedic trauma patients.

PURPOSE: Opioids have long been a mainstay of treatment for pain in patients with orthopaedic injuries, but little is known about the accuracy of self-reported narcotic usage in orthopaedic trauma. The purpose of this study is to evaluate the accuracy of self-reported opioid usage in orthopaedic trauma patients. METHODS: A retrospective review of all new patients presenting to the orthopaedic trauma clinic of a level 1 trauma centre with a chief complaint of recent orthopaedic-related injury over a 2-year time frame was conducted. Participants were administered a survey inquiring about narcotic usage within the prior 3 months. Responses were cross-referenced against a query of a statewide prescription drug monitoring program system. RESULTS: The study comprised 241 participants; 206 (85.5%) were accurate reporters, while 35 (14.5%) were inaccurate reporters. Significantly increased accuracy was associated with hospital admission prior to clinic visit (ß = - 1.33; χ2 = 10.68, P < 0.01; OR: 0.07, 95% CI 0.01-0.62). Decreased accuracy was associated with higher pre-visit total morphine equivalent dose (MED) (ß = 0.002; χ2 = 11.30, P < 0.01), with accurate reporters having significantly lower pre-index visit MED levels compared to underreporters (89.2 ± 208.7 mg vs. 249.6 ± 509.3 mg; P = 0.04). An Emergency Department (ED) visit prior to the index visit significantly predicted underreporting (ß = 0.424; χ2 = 4.28, P = 0.04; OR: 2.34, 95% CI 1.01-5.38). CONCLUSION: This study suggests that most new patients presenting to an orthopaedic trauma clinic with acute injury will accurately report their narcotic usage within the preceding 3 months. Prior hospital admissions increased the likelihood of accurate reporting while higher MEDs or an ED visit prior to the initial visit increased the likelihood of underreporting.

Astrocytes in Paper Chips and Their Interaction with Hybrid Vesicles.

The role of astrocytes in brain function has received increased attention lately due to their critical role in brain development and function under physiological and pathophysiological conditions. However, the biological evaluation of soft material nanoparticles in astrocytes remains unexplored. Here, the interaction of crosslinked hybrid vesicles (HVs) and either C8-D1A astrocytes or primary astrocytes cultured in polystyrene tissue culture or floatable paper-based chips is investigated. The amphiphilic block copolymer poly(cholesteryl methacrylate)-block-poly(2-carboxyethyl acrylate) (P1) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine lipids are used for the assembly of HVs with crosslinked membranes. The assemblies show no short-term toxicity towards the C8-D1A astrocytes and the primary astrocytes, and both cell types internalize the HVs when cultured in 2D cell culture. Further, it is demonstrated that both the C8-D1A astrocytes and the primary astrocytes could mature in paper-based chips with preserved calcium signaling and glial fibrillary acidic protein expression. Last, it is confirmed that both types of astrocytes could internalize the HVs when cultured in paper-based chips. These findings lay out a fundamental understanding of the interaction between soft material nanoparticles and astrocytes, even when primary astrocytes are cultured in paper-based chips offering a 3D environment.

Responsible (use of) AI.

Although there is a rich history of philosophical definitions of ethics when applied to human behavior, applying the same concepts and principles to AI may be fraught with problems. Anthropomorphizing AI to have characteristics such as "ethics" may promote a dangerous, unrealistic expectation that AI can be trained to have inherent, guaranteed ethical behavior. The authors instead advocate for increased research into the ethical use of AI from initial ideation and design through operational use and sustainment. The authors advocate for five key research areas: (1) education in ethics and core AI concepts for AI developers, leaders, and users, (2) development and use of model cards or datasheets for datasets to provide transparency into the strengths, limits, and potential biases of a trained model, (3) employing human-centered design that seeks to understand human value structures within a task context and enable effective human-machine interaction through intuitive and transparent interfaces, (4) targeted use of run time assurance that monitors and modifies the inputs or outputs of a trained model when necessary to enforce ethical principles such as safety or limiting bias, and (5) developing best practices for the use of a joint human-AI co-creation and training experience to enable a shared mental model and higher performance through potential emergent behavior.

Epidemiology of patellar dislocations in the United States from 2001 to 2020: results of a national emergency department database.

OBJECTIVES: Recent studies have shown an increasing incidence of patellar dislocations among children and adolescents. Updated, population-based studies of all patellar dislocations in the United States (US), however, are lacking. This study investigated recent trends in injury rates and demographics among patients sustaining patellar dislocations in the US from 2001 to 2020. METHODS: This descriptive epidemiologic study retrospectively analyzed the National Electronic Injury Surveillance System (NEISS) database to identify cases of acute patellar dislocations presenting to US Emergency Departments (EDs) from 2001 to 2020. Annual, overall, and age-adjusted incidence rates (IRs, expressed per 100,000 at-risk person-years) and additional patient/injury characteristics were analyzed. Average annual percent change (AAPC) estimates are presented to indicate the magnitude/direction of trends in annual injury rates. RESULTS: An estimated total of 159,529 patellar dislocations occurred over the study period for an overall IR of 2.58 (95% CI = 2.04-3.12). Accounting for population growth, the overall annual incidence increased significantly from 2.61 in 2001 to 3.0 in 2020 (AAPC = 2.8, p < 0.0001). When considering sex and age, statistically significant increases in annual IRs were observed among males aged 10-19 years (AAPC = 3.8, p < 0.0001), females aged 10-19 years (AAPC = 5.3, p < 0.0001), and females aged 20-29 years (AAPC = 3.5, p = 0.0152), while no significant changes were observed in any other age groups. Two-thirds of patellar dislocations involved sports-related injury mechanisms. The annual incidence of both sports-related and non-sports-related injuries increased significantly over the study period (sports-related: AAPC = 2.6, p = 0.0001; non-sports-related: AAPC = 3.4, p = 0.0001). Athletic patellar dislocations occurred most commonly in basketball and dance. CONCLUSION: The number of patients sustaining patellar dislocations is increasing in the US. Similar increasing trends were observed in both males and females aged 10-19 years, whereas injury rates increased in the third decade only among females. A large percentage of injuries occur during athletic activity, but both sports- and non-sports-related patellar dislocations are on the rise.

The Effect of Asset Degradation on Trust in Swarms: A Reexamination of System-Wide Trust in Human-Swarm Interaction.

OBJECTIVE: The effects of asset degradation on trust in human-swarm interaction were investigated through the lens of system-wide trust theory. BACKGROUND: Researchers have begun investigating contextual features that shape human interactions with robotic swarms-systems comprising assets that coordinate behavior based on their nearest neighbors. Recent work has begun investigating how human trust toward swarms is affected by asset degradation through the lens of system-wide trust theory, but these studies have been marked by several limitations. METHOD: In an online study, the current work manipulated asset degradation and measured trust-relevant criteria in a within-subjects design and addressed the limitations of past work. RESULTS: Controlling for swarm performance (i.e., target acquisition), asset degradation and trust (i.e., reliance intentions) in swarms were negatively related. In addition, as degradation increased, perceptions of swarm cohesion, obstacle avoidance, target acquisition, and terrain exploration efficiency decreased, the latter two of which (coupled with the reliance intentions criterion) support the tenets of system-wide trust theory as well as replicate and extend past work on the effects of asset degradation on trust in swarms. CONCLUSION: Human-swarm interaction is a context in which system-wide trust is relevant, and future work ought to investigate how to calibrate human trust toward swarm systems. APPLICATIONS: Based on these findings, design professionals should prioritize ways to depict swarm performance and system health such that humans do not abandon trust in systems that are still functional yet not over-trust those systems which are indeed performing poorly.

Funding has no effect on clinical outcomes of total joint arthroplasty emerging technologies: a systematic review of bibliometrics and conflicts of interest.

BACKGROUND: The use of new total joint arthroplasty technologies, including patient-specific implants/instrumentation (PSI), computer-assisted (CA), and robotic-assisted (RA) techniques, is increasing. There is an ongoing debate regarding the value provided and potential concerns about conflicts of interest (COI). METHODS: PRISMA guidelines were followed. PubMed, MEDLINE, and Web of Science databases were searched for total hip and knee arthroplasties, unicompartmental knee arthroplasties (UKA), PSI, CA, and RA. Bibliometric data, financial COI, clinical/functional scores, and patient-reported outcomes were assessed. RESULTS: Eighty-seven studies were evaluated, with 35 (40.2%) including at least one author reporting COI, and 13 (14.9%) disclosing industry funding. COI and industry funding had no significant effects on outcomes (P = 0.682, P = 0.447), and there were no significant effects of conflicts or funding on level of evidence (P = 0.508, P = 0.826). Studies in which author(s) disclosed COI had significantly higher relative citation ratio (RCR) and impact factor (IF) than those without (P < 0.001, P = 0.032). Subanalysis demonstrated RA and PSI studies were more likely to report COI or industry funding (P = 0.045). RA (OR = 6.31, 95% CI: 1.61-24.68) and UKA (OR = 9.14, 95% CI: 1.43-58.53) had higher odds of reporting favorable outcomes than PSI. CONCLUSIONS: Author COIs (about 40%) may be lower than previously reported in orthopedic technologies/techniques reviews. Studies utilizing RA and PSI were more likely to report COI, while RA and UKA studies were more likely to report favorable outcomes than PSI. No statistically significant association between the presence of COIs and/or industry funding and the frequency of favorable outcomes or study level of evidence was found. LEVEL OF EVIDENCE: Level V Systematic Review.

Effects of veterans' mental health service-connections on patient-reported outcomes following total joint arthroplasty.

Background: Studies report poor outcomes of elective orthopaedic surgeries among civilian patients receiving Workers' Compensation (WC). However, little is known about surgical outcomes in veterans receiving similar benefits through the Veterans Affairs (VA) service-connected (SC) disability compensation program. Methods: Veterans undergoing primary total hip arthroplasty (THA) or total knee arthroplasty (TKA) at a VA Medical Center between 07/2019-12/2021 were analyzed by SC status. Outcomes were evaluated using Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR) and Knee injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) scores collected preoperatively and at 2- and 12-months postoperatively. Repeated measures mixed models were used to test for the effect of SC on HOOS-JR/KOOS-JR scores, controlling for baseline age, sex, and Charlson Comorbidity Index (CCI). SC and baseline joint function (stratified into quartiles using baseline HOOS-JR/KOOS-JR scores) were analyzed for effects on achieving substantial clinical benefit (SCB) at 12-month follow-up. Results: The analysis included 67 hips and 142 knees. SC and non-SC (NSC) veterans had similar baseline HOOS-JR/KOOS-JR and CCI. HOOS-JR remained similar between groups through 12 months (79.9 ± 19.2 vs. 82.7 ± 18.8) as did KOOS-JR (70.4 ± 15.6 vs. 74.6 ± 15.3). The designation of any SC and mental health SC reached significance for KOOS-JR (P = 0.034 and P = 0.032, respectively). For HOOS-JR and KOOS-JR, baseline function score quartile significantly influenced final score (P < 0.001), with patients in the lowest quartiles (i.e., worst baseline function) exhibiting significantly greater improvements than patients in higher quartiles. Conclusions: Mental health SC and high preoperative functional status are variables that may have unfavorable influences on self-reported outcomes of TKA in veteran patients. SC status does not appear to influence the outcomes of THA or the likelihood of achieving SCB after either THA or TKA. Regardless of SC status, most veterans can expect significant clinical improvements after total joint arthroplasty.

Cryo-EM structure of the human NKCC1 transporter reveals mechanisms of ion coupling and specificity.

The sodium-potassium-chloride transporter NKCC1 of the SLC12 family performs Na+ -dependent Cl- - and K+ -ion uptake across plasma membranes. NKCC1 is important for regulating cell volume, hearing, blood pressure, and regulation of hyperpolarizing GABAergic and glycinergic signaling in the central nervous system. Here, we present a 2.6 Å resolution cryo-electron microscopy structure of human NKCC1 in the substrate-loaded (Na+ , K+ , and 2 Cl- ) and occluded, inward-facing state that has also been observed for the SLC6-type transporters MhsT and LeuT. Cl- binding at the Cl1 site together with the nearby K+ ion provides a crucial bridge between the LeuT-fold scaffold and bundle domains. Cl- -ion binding at the Cl2 site seems to undertake a structural role similar to conserved glutamate of SLC6 transporters and may allow for Cl- -sensitive regulation of transport. Supported by functional studies in mammalian cells and computational simulations, we describe a putative Na+ release pathway along transmembrane helix 5 coupled to the Cl2 site. The results provide insight into the structure-function relationship of NKCC1 with broader implications for other SLC12 family members.

Epidemiology of ballistic fractures in the United States: A 20-year analysis of the Firearm Injury Surveillance Study.

INTRODUCTION: Ballistic (i.e., gunshot-induced) fractures present unique treatment challenges and can be associated with high rates of complications and considerable morbidity. Large-scale epidemiologic data on these types of fractures are scarce. There is concern that gun-related violence may be on the rise, potentially increasing the burden of ballistic orthopaedic trauma, but there are few contemporary studies on the topic. The aim of this study, therefore, was to investigate the incidence and demographics of patients with ballistic fractures in the United States (US) over the last 20 years. MATERIALS AND METHODS: This descriptive epidemiology study retrospectively analyzed the Firearm Injury Surveillance Study to identify cases of ballistic fractures in the US from 2000 to 2019. Overall and annual numbers of fractures and fracture incidence rates (IRs), patient demographics, incident characteristics, and temporal trends were analyzed. Patients of all ages were included. Ballistic fractures were grouped by anatomic location for comparisons (non-spine axial, spine, upper extremity, lower extremity). RESULTS: An estimated N = 240,555 patients (n = 8,322 unweighted cases) sustained ballistic fractures over the 20-year study period for an overall IR of 39.2 per 1,000,000 person-years at-risk (PYR). Overall, lower extremity fractures accounted for the largest percentage of cases (45.9%; IR=18.8 PYR), followed by upper extremity fractures (32.8%; IR=13.4 PYR), non-spine axial fractures (16.1%; IR=6.6 PYR), and spine fractures (5.2%; IR=2.1 PYR). Diaphyseal femur fractures were the most common ballistic fractures overall. Nearly three-fourths (71.2%) of all cases occurred in males in the second through fourth decades. The most common injury intent was assault (71.8%) and a majority of patients (71.2%) required hospital admission. Accounting for population growth yielded a significantly increasing incidence of all ballistic fractures over the study period from 15.7 PYR in 2000 to 96.8 PYR in 2019 (average annual percent change=10.3, p < 0.00001). CONCLUSION: These data suggest that the nationwide burden of ballistic fractures in the US has increased significantly in the last two decades. Ballistic fractures are associated with significant morbidity and societal cost, and increasing injury rates highlight the need for future research aimed at better understanding the ideal treatment of these types of fractures and their outcomes.

Variations on a theme: crystal forms of the amino-acid transporter MhsT.

The bacterial amino-acid transporter MhsT from the SLC6A family has been crystallized in complex with different substrates in order to understand the determinants of the substrate specificity of the transporter. Surprisingly, crystals of the different MhsT-substrate complexes showed interrelated but different crystal-packing arrangements. Space-group assignment and structure determination of these different crystal forms present challenging combinations of pseudosymmetry, twinning and translational noncrystallographic symmetry.