Measured distance from posterior tibia to popliteal artery increases with flexion and subluxation of the knee.

Purpose: Popliteal artery laceration is a devastating complication in total knee arthroplasty (TKA). Its anatomic position relative to the tibia has been studied using ultrasound or magnetic resonance imaging. This is the first study performed in a laboratory using radiographic measurements to determine if increased flexion and subluxation of the knee increase the distance between the tibia and popliteal artery. Methods: The femoral artery was infused with radiopaque dye in six cadavers. The knee was placed in two different degrees of flexion and three of subluxation. The radiographic distance between standardized markers in the posterior tibia and popliteal artery was measured. Results: The average distance from the tibial peg to the popliteal artery at 90° of flexion increased from 0% to 50% to 100% subluxation. The increase was statistically significant (Friedman test p = 0.016). The contrast between neutral and 100% subluxation was statistically significant (Sign test p = 0.031). At 115° flexion, average distance from the peg to popliteal artery significantly increased as subluxation increased (Friedman test p = 0.05). In three specimens, at 115° of flexion and 100% subluxation, a line perpendicular to the axis of the tibia, failed to intersect the popliteal artery. The measured distance increased from 90° to 115° of flexion at a given degree of subluxation, but this difference did not reach statistical significance. Conclusions: Increasing flexion and subluxation of the tibia results in increasing distance between the cut plane of the tibial plateau and popliteal artery and decreases risk of laceration. Level of Evidence: Not applicable.

Metabolite Study and Structural Authentication for the First-in-Human Use Sphingosine-1-phosphate Receptor 1 Radiotracer.

The sphingosine-1-phosphate receptor 1 (S1PR1) radiotracer [11C]CS1P1 has shown promise in proof-of-concept PET imaging of neuroinflammation in multiple sclerosis (MS). Our HPLC radiometabolite analysis of human plasma samples collected during PET scans with [11C]CS1P1 detected a radiometabolite peak that is more lipophilic than [11C]CS1P1. Radiolabeled metabolites that cross the blood-brain barrier complicate quantitative modeling of neuroimaging tracers; thus, characterizing such radiometabolites is important. Here, we report our detailed investigation of the metabolite profile of [11C]CS1P1 in rats, nonhuman primates, and humans. CS1P1 is a fluorine-containing ligand that we labeled with C-11 or F-18 for preclinical studies; the brain uptake was similar for both radiotracers. The same lipophilic radiometabolite found in human studies also was observed in plasma samples of rats and NHPs for CS1P1 labeled with either C-11 or F-18. We characterized the metabolite in detail using rats after injection of the nonradioactive CS1P1. To authenticate the molecular structure of this radiometabolite, we injected rats with 8 mg/kg of CS1P1 to collect plasma for solvent extraction and HPLC injection, followed by LC/MS analysis of the same metabolite. The LC/MS data indicated in vivo mono-oxidation of CS1P1 produces the metabolite. Subsequently, we synthesized three different mono-oxidized derivatives of CS1P1 for further investigation. Comparing the retention times of the mono-oxidized derivatives with the metabolite observed in rats injected with CS1P1 identified the metabolite as N-oxide 1, also named TZ82121. The MS fragmentation pattern of N-oxide 1 also matched that of the major metabolite in rat plasma. To confirm that metabolite TZ82121 does not enter the brain, we radiosynthesized [18F]TZ82121 by the oxidation of [18F]FS1P1. Radio-HPLC analysis confirmed that [18F]TZ82121 matched the radiometabolite observed in rat plasma post injection of [18F]FS1P1. Furthermore, the acute biodistribution study in SD rats and PET brain imaging in a nonhuman primate showed that [18F]TZ82121 does not enter the rat or nonhuman primate brain. Consequently, we concluded that the major lipophilic radiometabolite N-oxide [11C]TZ82121, detected in human plasma post injection of [11C]CS1P1, does not enter the brain to confound quantitative PET data analysis. [11C]CS1P1 is a promising S1PR1 radiotracer for detecting S1PR1 expression in the CNS.

A metagenomic investigation of phytoplasma diversity in Australian vegetable growing regions.

In this study, metagenomic sequence data was used to investigate the phytoplasma taxonomic diversity in vegetable-growing regions across Australia. Metagenomic sequencing was performed on 195 phytoplasma-positive samples, originating either from historic collections (n=46) or during collection efforts between January 2015 and June 2022 (n=149). The sampled hosts were classified as crop (n=155), weed (n=24), ornamental (n=7), native plant (n=6), and insect (n=3) species. Most samples came from Queensland (n=78), followed by Western Australia (n=46), the Northern Territory (n=32), New South Wales (n=17), and Victoria (n=10). Of the 195 draft phytoplasma genomes, 178 met our genome criteria for comparison using an average nucleotide identity approach. Ten distinct phytoplasma species were identified and could be classified within the 16SrII, 16SrXII (PCR only), 16SrXXV, and 16SrXXXVIII phytoplasma groups, which have all previously been recorded in Australia. The most commonly detected phytoplasma taxa in this study were species and subspecies classified within the 16SrII group (n=153), followed by strains within the 16SrXXXVIII group ('Ca. Phytoplasma stylosanthis'; n=6). Several geographic- and host-range expansions were reported, as well as mixed phytoplasma infections of 16SrII taxa and 'Ca. Phytoplasma stylosanthis'. Additionally, six previously unrecorded 16SrII taxa were identified, including five putative subspecies of 'Ca. Phytoplasma australasiaticum' and a new putative 16SrII species. PCR and sequencing of the 16S rRNA gene was a suitable triage tool for preliminary phytoplasma detection. Metagenomic sequencing, however, allowed for higher-resolution identification of the phytoplasmas, including mixed infections, than was afforded by only direct Sanger sequencing of the 16S rRNA gene. Since the metagenomic approach theoretically obtains sequences of all organisms in a sample, this approach was useful to confirm the host family, genus, and/or species. In addition to improving our understanding of the phytoplasma species that affect crop production in Australia, the study also significantly expands the genomic sequence data available in public sequence repositories to contribute to phytoplasma molecular epidemiology studies, revision of taxonomy, and improved diagnostics.

Screening for Asymptomatic Osteonecrosis of the Hip in Systemic Lupus Erythematous: A Systematic Review and Meta-Analysis of MRI-Based Prevalence.

Objective. This paper aims to estimate asymptomatic hip osteonecrosis prevalence in SLE patients using MRI examination and to determine the prevalence among higher risk subpopulations. Materials and Methods. PubMed, Embase, Cochrane, and SCOPUS were searched from inception to May 9th, 2023. Studies on patients who were clinically diagnosed with systemic lupus erythematosus without reported symptoms attributable to hip osteonecrosis were included. Two independent reviewers extracted data and assessed the risk of bias. Data collected from each study include the study year, the number of hips screened, the number of hips with osteonecrosis, demographics, laboratory data, medications, follow-up time, radiological protocols, and MRI-based osteonecrosis detection and grading criteria. Results. Eleven eligible studies including 503 participants (15-35 years old; 74-100% female) with SLE were identified. Significant risk of bias was determined in one study. The overall prevalence of osteonecrosis of the hip was found to be 14% (184/1006 hip joints, 95% confidence interval: 7-22%, number needed to scan: 7.1). SLE patients who received corticosteroid treatment had a higher prevalence of asymptomatic hip osteonecrosis (18%) compared to non-corticosteroid users (0%, p-value < 0.01). Additionally, meta-regression results revealed that daily corticosteroid dose was associated with increased prevalence of asymptomatic osteonecrosis (0.5%/milligram, p-value < 0.01). Conclusions. The high prevalence of asymptomatic hip osteonecrosis in SLE patients raises concerns about the timeliness of interventions. The limitations of this study include a relatively low number of identified studies; and one study lacked full-text availability.

Genomic variation in pepper vein yellows viruses in Australia, including a new putative variant, PeVYV-10.

Since the first identification and full sequence of the polerovirus pepper vein yellows virus in Australia in 2016, virus surveys of crops and weeds have sporadically identified PeVYV in different hosts and locations. Genomic comparisons of 14 PeVYV-like isolates using RT-PCR products spanning the 3' end of the RdRp region (ORF 2), the intergenic region, ORF 3a, ORF 4, and ORF 3 (1388 nt) showed that four of the PeVYV isolates might be a new variant or PeVYV-like virus. From six PeVYV-positive plants, eight PeVYV-like sequences were obtained by high-throughput sequencing, as two hosts, 5352 and 5634, contained two slightly different PeVYV-like isolates. Three of the PeVYV-like isolates were most closely related to PeVYV-6 and PeVYV-5, and two isolates were closely related to PeVYV-9 and PeVYV-2. The other three isolates shared only 69-74% nucleotide sequence identity across the whole genome with any of the other PeVYVs, despite sharing 73-98%, 87-91%, and 84-87% amino acid sequence identity in ORF 3a, ORF 3, and the RdRp (ORF 2), respectively, suggesting that this virus is a new PeVYV-like virus, which we have tentatively called PeVYV-10. This is also the first report of a PeVYV-like virus infecting garlic.

The Pregnant Arthroplasty Surgeon: A Women in Arthroplasty Committee Editorial.

BACKGROUND: Women orthopaedic surgeons face unique challenges during their careers. There are extremely low numbers of women in the field, particularly in the specialty of adult reconstruction. Factors contributing to low numbers of women entering this subspecialty include increased perceived physical demand relative to other fields, occupational hazards during pregnancy such as exposure to radiation and polymethylmethacrylate bone cement, concerns for work-life balance, and limited number of women within the subspecialty. The following editorial provides a framework to understand and manage the potential occupational hazards to pregnant and lactating surgeons, parental leave, and postpartum return to work. We aim to dispel any unfounded myths and provide evidence-based education that may help overcome these barriers. In doing so, we hope to encourage more women to consider adult reconstruction as a potential career. METHODS: Our primary method consisted of completing an extensive literature review on the past and current articles about the aforementioned barriers which may contribute to the low number of women entering adult reconstruction. After this literature search was completed, we composed a comprehensive editorial that provided evidence-based education and recommendations for medical professionals. CONCLUSIONS: Issues pertaining to parenthood, pregnancy, and lactation pose barriers to success for women in orthopedic surgery. These concerns may dissuade talented women from pursuing a rewarding career in adult reconstruction. Education on these issues is needed to help our early-career colleagues plan and care for their families. Clearly stated and published policies should be made available in all training programs, fellowships, and clinical practices to allow understanding and unbiased implementation. By being more inclusive, adult reconstruction will have access to the best possible surgeons, which will benefit not only patients but the field as a whole.

Effect of Patient Age on Total Hip Arthroplasty Outcomes in Patients Who Have Osteonecrosis of the Femoral Head Compared to Patients Who Have Hip Osteoarthritis.

BACKGROUND: Osteonecrosis of the femoral head (ONFH) affects both young and old patients. However, outcomes following total hip arthroplasty (THA) for these patients may vary with age. This study aimed to examine the effect of age on THA outcomes for non-traumatic ONFH patients, an area currently lacking research. METHODS: Patients who had non-traumatic ONFH undergoing THA with at least 2 years of follow-up were identified using a database and divided into four groups by age. Then, 4 matched control groups of patients who had hip osteoarthritis (OA) were created. Multivariate logistic regression analyses were used to evaluate the rates of medical and surgical complications. Additionally, cohorts with a minimum 5-year follow-up were filtered to obtain further data on surgical outcomes. The study analyzed 85,462 non-traumatic ONFH and 80,120 hip OA patients undergoing THA. RESULTS: Multiple medical complications in ONFH patients increased with age. Periprosthetic fracture within 2 years increased with age, while 90-day wound complications, 2-year periprosthetic joint infections, dislocations, and revisions decreased. The trends for complications continued at the 5-year follow-up. Compared to OA patients, those who had ONFH had higher risks of most complications, but this discrepancy decreased with age. CONCLUSIONS: In ONFH patients undergoing THA, medical complications generally rise with age, while most surgical complications, including revisions, decrease. It is notable that ONFH patients experienced more complications than those who had OA, but this difference diminished with age.

The observation of taxonomic boundaries for the 16SrII and 16SrXXV phytoplasmas using genome-based delimitation.

Within the 16SrII phytoplasma group, subgroups A-X have been classified based on restriction fragment length polymorphism of their 16S rRNA gene, and two species have been described, namely 'Candidatus Phytoplasma aurantifolia' and 'Ca. Phytoplasma australasia'. Strains of 16SrII phytoplasmas are detected across a broad geographic range within Africa, Asia, Australia, Europe and North and South America. Historically, all members of the 16SrII group share ≥97.5 % nucleotide sequence identity of their 16S rRNA gene. In this study, we used whole genome sequences to identify the species boundaries within the 16SrII group. Whole genome analyses were done using 42 phytoplasma strains classified into seven 16SrII subgroups, five 16SrII taxa without official 16Sr subgroup classifications, and one 16SrXXV-A phytoplasma strain used as an outgroup taxon. Based on phylogenomic analyses as well as whole genome average nucleotide and average amino acid identity (ANI and AAI), eight distinct 16SrII taxa equivalent to species were identified, six of which are novel descriptions. Strains within the same species had ANI and AAI values of >97 %, and shared ≥80 % of their genomic segments based on the ANI analysis. Species also had distinct biological and/or ecological features. A 16SrII subgroup often represented a distinct species, e.g., the 16SrII-B subgroup members. Members classified within the 16SrII-A, 16SrII-D, and 16SrII-V subgroups as well as strains classified as sweet potato little leaf phytoplasmas fulfilled criteria to be included as members of a single species, but with subspecies-level relationships with each other. The 16SrXXV-A taxon was also described as a novel phytoplasma species and, based on criteria used for other bacterial families, provided evidence that it could be classified as a distinct genus from the 16SrII phytoplasmas. As more phytoplasma genome sequences become available, the classification system of these bacteria can be further refined at the genus, species, and subspecies taxonomic ranks.

Increasing trend toward joint-preserving procedures for hip osteonecrosis in the United States from 2010 to 2019.

INTRODUCTION: The incidence of osteonecrosis of the femoral head is estimated at about 10 to 20,000 patients annually, and, when left untreated, 80% or more of cases progress to femoral head collapse. A series of joint-preserving procedures have been developed to prevent/delay the need for hip arthroplasty. The aim of this study was to provide a five-year update: (1) evaluating temporal trends of arthroplasty vs. joint-preservation techniques such as core decompression, bone grafting, osteotomies, and arthroscopy; (2) determining proportions of procedures in patients aged less than vs. over 50 years; and (3) quantifying rates of specific operative techniques. METHODS: A total of 10,334 patients diagnosed with osteonecrosis of the femoral head and having received hip surgery were identified from a nationwide database between 1 January 2010 and 31 December 2019, by using the International Classification of Disease, the Ninth/Tenth revision (ICD-9/10) codes. The percentage of patients managed by each operative procedure was calculated annually. To identify trends, patients were grouped by age under/over 50 years and divided into a joint-preserving and a non-joint-preserving (arthroplasty) group. Chi-squared tests were performed to compare the total number of procedures per year. RESULTS: Rates of arthroplasty far exceeded those for joint-preserving procedures. However, from 2015 to 2019, significantly more joint-preserving procedures were performed than in 2010 to 2014 (4.3% vs. 3.0%, P < 0.001). Significantly more joint-preserving procedures were performed in patients aged < 50 years relative to those ≥ 50 years (7.56% vs. 1.86%, P < 0.001). Overall, total hip arthroplasty was the most common procedure (9,814; 94.97%) relative to core decompression (331; 3.20%), hemiarthroplasty/resurfacing (102; 0.99%), bone grafting (48; 0.46%), and osteotomy (5; 0.05%). CONCLUSION: Management of patients who have osteonecrosis of the femoral head continues to be predominantly arthroplasty procedures, specifically, total hip arthroplasty. Our findings suggest a small, but significant trend toward increased joint-preserving procedures, especially in patients under 50 years. In particular, the proportion of patients receiving core decompression has increased significantly from 2015 to 2019 relative to prior years.

Trends in Surgical Management of Osteonecrosis of the Femoral Head: A 2010 to 2020 Nationwide Study.

BACKGROUND: The incidence of osteonecrosis of the femoral head (ONFH) is estimated at more than 20,000 patients annually in the US. Our study aimed to provide a 10-year analysis: 1) evaluating total operative procedures with rates normalized to the population; 2) determining trends of arthroplasty versus joint-preserving procedures; and 3) quantifying specific operative techniques in patients <50 versus >50 years of age. METHODS: A total of 64,739 patients who were diagnosed with ONFH and underwent hip surgery were identified from a nationwide database between 2010 and 2020. The percentage of patients managed by each operative procedure was calculated and normalized to the overall population annually. Patients were grouped into joint-preserving versus non-joint-preserving (arthroplasty) procedures, and divided by age under/over 50 years. Linear regression modeling was performed to evaluate trends/differences in procedural volume by year. RESULTS: The number of operative procedures to treat ONFH has relatively declined from 2010 to 2020. The relative proportion of joint-preserving procedures increased (8.6% to 11.2%) during this time period. There were significantly more joint-preserving procedures in patients aged <50 years relative to >50 years (15.3% versus 2.7%, P < .001). Overall, THA was the most common procedure (57,033;88.1%) relative to hemiarthroplasty (3,875;6.0%), core decompression (2,730;4.2%), bone graft (467;0.7%), and osteotomy (257;0.4%). CONCLUSION: Surgical management of patients who have ONFH remains predominantly arthroplasty procedures (94% overall). Our findings suggest an increase in joint-preserving procedures, particularly core decompression, in patients <50 years (15.3%). Our findings provide insight into surgical management trends for ONFH, and suggest opportunities for joint-preserving procedures.

Patients' experiences and compliance with preoperative screening and decolonization.

BACKGROUND: To improve adherence with pre-surgical screening for Staphylococcus aureus nasal carriage and decolonization, we need more information about patients' experiences with these protocols. METHODS: We surveyed patients undergoing orthopedic, neurosurgical, or cardiac operations at Johns Hopkins Hospitals (JHH), the University of Iowa Hospitals and Clinics (UIHC) at MercyOne Northeast Iowa Neurosurgery (MONIN) to assess patients' experiences with decolonization protocols. RESULTS: Five hundred thirty-four patients responded. Respondents at JHH were significantly more likely than those at the UIHC to report using mupirocin and were significantly more likely than those at the UIHC and MONIN to feel they received adequate information about surgical site infection (SSI) prevention and decolonization. Respondents at JHH were the least likely to not worry about SSI and they were more willing to do anything they could to prevent SSI. Few patients reported barriers to adherence and side effects of mupirocin or chlorhexidine. CONCLUSION: Respondents did not report either major side effects or barriers to adherence. Patients varied in their level of concern about SSI, their willingness to invest effort in preventing SSI, and their assessments of preoperative information. To improve patients' adherence, clinicians and hospitals should assess their patients' needs and desires and tailor their preoperative processes, education, and prophylaxis accordingly.

Development of a personalized shared decision-making tool for knee osteoarthritis and user-testing with African American and Latina women.

Background: Patients with chronic knee pain are often unaware of treatment options and likely outcomes-information that is critical to decision-making. A consistent framework for communicating patient-personalized information enables clinicians to provide consistent, targeted, and relevant information. Our objective was to user-test a shared decision-making (SDM) tool for chronic knee pain. Methods: A cross-functional team developed a Markov-based health economics model and tested the model outputs with patient panels, patient and clinician focus groups, and clinical specialists. The resulting SDM tool was user-tested in a parallel-designed, randomized controlled study with 52 African American and 52 Latina women from geographically representative areas of the US. Participants were randomized to counseling with or without the SDM tool. Feedback was collected at intervention and at 1 month after intervention and analyzed with Student's t-tests and Chi-squared analyses (alpha = 0.05). Results: Qualitative results indicated patients understood the material, rated the overall experience highly, and were likely to recommend the physician. The SDM group reported high satisfaction with the tool. A greater proportion of the SDM group (56%) reported increased physical activity over baseline at 1 month compared with the control group (33%) (P = 0.0005). New use of medications for knee pain (58% SDM; 49% control) did not differ significantly between groups (P = 0.15). Conclusion: Use of this innovative SDM tool was associated with high satisfaction and a significant increase in self-reported physical activity level at 1 month. The SDM tool may elicit behavioral changes to promote musculoskeletal health.