152 results on '"Keller RA"'
Search Results
2. Effect of weighing uncertainty on assay values by isotope dilution mass spectrometry
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Chelsea Ottenfeld, Christine E. Mathew, Keller Ra, and V. K. Rai
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Radionuclide ,Materials science ,Isotope ,Health, Toxicology and Mutagenesis ,Instrumentation ,Public Health, Environmental and Occupational Health ,Analytical chemistry ,Thermal ionization ,Actinide ,Isotope dilution ,010403 inorganic & nuclear chemistry ,Mass spectrometry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Analytical Chemistry ,Nuclear Energy and Engineering ,Radiology, Nuclear Medicine and imaging ,Inductively coupled plasma ,Spectroscopy - Abstract
Isotope dilution mass spectrometry using traceable standards as spikes coupled with isotope ratio measurements by thermal ionization or inductively coupled plasma mass spectrometer instruments is the preferred methodology for element content determinations and isotopic composition measurements in a variety of applications, especially those involving highly radioactive isotopes like the actinide elements. This assay measurement technique takes advantage of the sensitivity of modern mass spectrometry instrumentation to minimize the amount of material utilized for the measurement and enables the measurement sequence to be automated, with minimal intervention from analyst during the measurement process. LA-UR-20-28878.
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- 2021
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3. Systematic bias in the 240Pu/239Pu isotopic ratio of plutonium isotopic standard CRM138
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K. J. Mathew, Chelsea Ottenfeld, Alice K. Slemmons, and Keller Ra
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Isotope ,Health, Toxicology and Mutagenesis ,010401 analytical chemistry ,Radiochemistry ,Public Health, Environmental and Occupational Health ,chemistry.chemical_element ,Thermal ionization mass spectrometry ,Uranium ,010403 inorganic & nuclear chemistry ,Mass spectrometry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Analytical Chemistry ,Plutonium ,Certified reference materials ,Isotopic ratio ,Nuclear Energy and Engineering ,chemistry ,Environmental science ,Radiology, Nuclear Medicine and imaging ,Inductively coupled plasma ,Spectroscopy - Abstract
Plutonium certified reference materials (CRMs) 136, 137, and 138 were produced, characterized, and certified in the period 1966 through 1971 by the National Bureau of Standards. The thermal ionization mass spectrometry (TIMS) instruments and the analytical methodologies evolved significantly since the characterization of these Pu isotopic standards. Given the excellent precision of modern TIMS and inductively coupled plasma instruments, systematic biases at the major and minor isotope ratios of these plutonium (Pu) isotopic standards (compared to the certified values) are to be expected. Studies on the major and minor isotope ratios of uranium (U) CRMs indicated systematic bias in the certified ratios of several of these standards. We present a systematic investigation of the 240Pu/239Pu major isotope ratio of Pu isotopic CRM138. The 240Pu/239Pu isotope ratio is shown to be biased by ~ 0.07–0.08%, larger than the bias seen in the major isotope ratio of any of the U CRM from New Brunswick Laboratory (NBL).
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- 2018
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4. Intercomparison of the Radio-Chronometric Ages of Plutonium-Certified Reference Materials with Distinct Isotopic Compositions
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K. J. Mathew, Ross W. Williams, Joanna S. Denton, Mariam R. Thomas, Floyd E. Stanley, Tara Mastren, Adrian Nicholl, Andrew J. Gaunt, Keller Ra, Tashi Parsons-Davis, Katherine Garduno, Amy M. Gaffney, William S. Kinman, Josh Wimpenny, Theresa M. Kayzar-Boggs, Klaus Mayer, James Brent Fulwyler, R. E. Steiner, Zsolt Varga, Dana Labotka, Allison Wende, Joel R. Maassen, Jung Rim, Maria Wallenius, Richard A. Torres, Elmer Lujan, Lav Tandon, Kerri C. Treinen, Iain May, John M. Rolison, Donivan R. Porterfield, Chelsea Ottenfeld, and J. D. Inglis
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Chemistry ,010401 analytical chemistry ,Mineralogy ,chemistry.chemical_element ,Thermal ionization ,Natural abundance ,Thermal ionization mass spectrometry ,010402 general chemistry ,Mass spectrometry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Plutonium ,Certified reference materials ,Inductively coupled plasma ,Inductively coupled plasma mass spectrometry - Abstract
An intercomparison of the radio-chronometric ages of four distinct plutonium-certified reference materials varying in chemical form, isotopic composition, and period of production are presented. The cross-comparison of the different 234U/238Pu, 235U/239Pu, 236U/240Pu, and 241Am/241Pu model purification ages obtained at four independent analytical facilities covering a range of laboratory environments from bulk sample processing to clean facilities dedicated to nuclear forensic investigation of environmental samples enables a true assessment of the state-of-practice in "age dating capabilities" for nuclear materials. The analytical techniques evaluated used modern mass spectrometer instrumentation including thermal ionization mass spectrometers and inductively coupled plasma mass spectrometers for isotopic abundance measurements. Both multicollector and single collector instruments were utilized to generate the data presented here. Consensus values established in this study make it possible to use these isotopic standards as quality control standards for radio-chronometry applications. Results highlight the need for plutonium isotopic standards that are certified for 234U/238Pu, 235U/239Pu, 236U/240Pu, and 241Am/241Pu model purification ages as well as other multigenerational radio-chronometers such as 237Np/241Pu. Due to the capabilities of modern analytical instrumentation, analytical laboratories that focus on trace level analyses can obtain model ages with marginally larger uncertainties than laboratories that handle bulk samples. When isotope ratio measurement techniques like thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry with comparable precision are utilized, model purification ages with similar uncertainties are obtained.
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- 2019
5. Chemical investigation of three plutonium–beryllium neutron sources
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Elmer Lujan, Lisa E Townsend, Lav Tandon, Kevin J. Kuhn, Alexander Martinez, Keller Ra, Lynn A. Foster, Donivan R. Porterfield, Mariam R. Thomas, Khal Spencer, Daniel S. Schwartz, Ning Xu, Lisa Michelle Colletti, Floyd E. Stanley, and Benjamin L. Byerly
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Health, Toxicology and Mutagenesis ,Nuclear engineering ,Nuclear forensics ,010401 analytical chemistry ,Public Health, Environmental and Occupational Health ,chemistry.chemical_element ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Analytical Chemistry ,Characterization (materials science) ,Plutonium ,Nuclear physics ,Nuclear Energy and Engineering ,chemistry ,Neutron source ,Radiology, Nuclear Medicine and imaging ,Beryllium ,Spectroscopy ,Transuranium element - Abstract
Thorough physical and chemical characterization of plutonium–beryllium (PuBe) neutron sources is an important capability with applications ranging from material accountancy to nuclear forensics. Characterization of PuBe sources is not trivial owing to range of existing source designs and the need for adequate infrastructure to deal with radiation and protect the analyst. This study demonstrates a method for characterization of three PuBe sources that includes physical inspection and imaging followed by controlled disassembly and destructive analysis.
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- 2017
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6. Determination of initial fuel state and number of reactor shutdowns in archived low-burnup uranium targets
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Keller Ra, Benjamin L. Byerly, Floyd E. Stanley, Khalil J. Spencer, Patrick T. Martinez, Ning Xu, Lav Tandon, Mariam R. Thomas, A. C. Hayes-Sterbenz, James Brent Fulwyler, and Michael Francis Schappert
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Fission products ,Nuclear fission product ,020209 energy ,Health, Toxicology and Mutagenesis ,Radiochemistry ,Public Health, Environmental and Occupational Health ,Radioactive waste ,chemistry.chemical_element ,02 engineering and technology ,Actinide ,Uranium ,010403 inorganic & nuclear chemistry ,01 natural sciences ,Pollution ,0104 chemical sciences ,Analytical Chemistry ,Plutonium ,Nuclear Energy and Engineering ,chemistry ,Neutron flux ,0202 electrical engineering, electronic engineering, information engineering ,Radiology, Nuclear Medicine and imaging ,Spectroscopy ,Burnup - Abstract
This study presents a method for destructive analysis of irradiated uranium (U) targets, with a focus on collection and measurement of long-lived (t 1/2 > ~10 years) and stable fission product isotopes of ruthenium and cesium. Long-lived and stable isotopes of these elements can provide information on reactor conditions (e.g. flux, irradiation time, cooling time) in old samples (>5–10 years) whose short-lived fission products have decayed away. The separation and analytical procedures were tested on archived U reactor targets at Los Alamos National Laboratory as part of an effort to evaluate reactor models at low-burnup.
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- 2015
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7. High-Throughput Flow Cytometric DNA Fragment Sizing
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Keller Ra, Van Orden A, and W.P. Ambrose
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medicine.diagnostic_test ,Chemistry ,Analytical chemistry ,Flow Cytometry ,Bacteriophage lambda ,Fluorescence ,Sizing ,Analytical Chemistry ,Flow cytometry ,Fragment size ,chemistry.chemical_compound ,Linear relationship ,DNA, Viral ,Kilobase pairs ,medicine ,Nucleic Acid Conformation ,Parallel imaging ,DNA ,Bacteriophage M13 - Abstract
The rate of detection and sizing of individual fluorescently labeled DNA fragments in conventional single-molecule flow cytometry (SMFC) is limited by optical saturation, photon-counting statistics, and fragment overlap to approximately 100 fragments/s. We have increased the detection rate for DNA fragment sizing in SMFC to approximately 2000 fragments/s by parallel imaging of the fluorescence from individual DNA molecules, stained with a fluorescent intercalating dye, as they passed through a planar sheet of excitation laser light, resulting in order of magnitude improvements in the measurement speed and the sample throughput compared to conventional SMFC. Fluorescence bursts were measured from a fM solution of DNA fragments ranging in size from 7 to 154 kilobase pairs. A data acquisition time of only a few seconds was sufficient to determine the DNA fragment size distribution. A linear relationship between the number of detected photons per burst and the DNA fragment size was confirmed. Application of this parallel fluorescence imaging method will lead to improvements in the speed, throughput, and sensitivity of other types of flow-based analyses involving the study of single molecules, chromosomes, cells, etc.
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- 1999
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8. Single Molecule Fluorescence Spectroscopy at Ambient Temperature
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James H. Werner, James H. Jett, Peter M. Goodwin, Van Orden A, W.P. Ambrose, and Keller Ra
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Chemistry ,General Chemistry ,Photochemistry ,Single-molecule experiment ,Spectroscopy - Published
- 1999
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9. Efficient detection of single DNA fragments in flowing sample streams by two-photon fluorescence excitation
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A. Van Orden, Peter M. Goodwin, Keller Ra, and Hong Cai
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medicine.diagnostic_test ,Base pair ,Analytical chemistry ,Laser ,Fluorescence ,Analytical Chemistry ,Flow cytometry ,law.invention ,Wavelength ,chemistry.chemical_compound ,chemistry ,law ,medicine ,Molecule ,DNA ,Excitation - Abstract
This paper reports the demonstration of efficient single molecule detection in flow cytometry by two-photon fluorescence excitation. We have used two-photon excitation (TPE) to detect single DNA fragments as small as 383 base pairs (bp) labeled with the intercalating dye, POPO-1, at a dye:nucleotide ratio of 1:5. TPE of the dye-DNA complexes was accomplished using a mode-locked, 120 fs pulse width Ti:sapphire laser operating at 810 nm. POPO-1 labeled DNA fragments of 1.1 kilobase pairs (kbp) and larger were sequentially detected in our flow cytometry system with a detection efficiency of nearly 100%. The detection efficiency for the 383 bp DNA fragments was approximately 75%. We also demonstrate the ability to distinguish between different sized DNA fragments in a mixture by their individual fluorescence burst sizes by TPE. These studies indicate that using TPE for single molecule flow cytometry experiments lowers the intensity of the background radiation by approximately an order of magnitude compared to one-photon excitation, due to the large separation between the excitation and emission wavelengths in TPE.
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- 2011
10. Single-molecule identification in flowing sample streams by fluorescence burst size and intraburst fluorescence decay rate
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A. Van Orden, Peter M. Goodwin, Nicholas P. Machara, and Keller Ra
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Rhodamine 6G ,chemistry.chemical_compound ,Wavelength ,chemistry ,Monte Carlo method ,Fluorescence spectrometry ,Analytical chemistry ,Molecule ,Multiplex ,Laser-induced fluorescence ,Fluorescence ,Analytical Chemistry - Abstract
We report a multiplex technique for identification of single fluorescent molecules in a flowing sample stream by correlated measurement of single-molecule fluorescence burst size and intraburst fluorescence decay rate. These quantities were measured simultaneously for single fluorescent molecules in a flowing sample stream containing a dilute mixture of fluorescent species: Rhodamine 6G and tetramethylrhodamine isothiocyanate. Using a detailed Monte Carlo simulation of our experiment, we calculate single-molecule detection efficiencies and confidence levels for identification of these species and identify major sources of error for single-molecule identification. The technique reported here is applicable to distinguishing between fluorophores with similar spectroscopic properties and requires only a single excitation wavelength and single fluorescence emission detection channel.
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- 2011
11. Fluorescence correlation spectroscopy for rapid multicomponent analysis in a capillary electrophoresis system
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Keller Ra and Van Orden A
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Chromatography ,Capillary electrophoresis ,Chemistry ,Fluorescence spectrometry ,Analytical chemistry ,Separation method ,lipids (amino acids, peptides, and proteins) ,Fluorescence correlation spectroscopy ,Trace analysis ,Analysis method ,Analytical Chemistry - Abstract
We describe a new technique for performing multicomponent analysis using a combination of capillary electrophoresis (CE) and fluorescence correlation spectroscopy (FCS), which we refer to as CE/FCS. FCS is a highly sensitive and rapid optical technique that is often used to perform multicomponent analysis in static solutions based on the different diffusion times of the analyte species through the detection region of a tightly focused laser beam. In CE/FCS, transit times are measured for a mixture of analytes continuously flowing through a microcapillary in the presence of an electric field. Application of an electric field between the inlet and outlet of the capillary alters the transit times, depending on the magnitude and polarity of the applied field and the electrophoretic mobilities of the analytes. Multicomponent analysis is accomplished without the need to perform a chemical separation, due to the different electrophoretic mobilities of the analytes. This technique is particularly applicable to ultradilute solutions of analyte. We have used CE/FCS to analyze subnanomolar aqueous solutions containing mixtures of Rhodamine 6G (R6G) and R6G-labeled deoxycytosine triphosphate nucleotides. Under these conditions, fewer than two molecules were typically present in the detection region at a time. The relative concentrations of the analytes were determined with uncertainties of ∼10%. Like diffusional FCS, this technique is highly sensitive and rapid. Concentration detection limits are below 10(-)(11) M, and analysis times are tens of seconds or less. However, CE/FCS does not require the diffusion coefficients of the analytes to be significantly different and can, therefore, be applied to multicomponent analysis of systems that would be difficult or impossible to study by diffusional FCS.
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- 2011
12. Rapid sizing of individual fluorescently stained DNA fragments by flow cytometry
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James H. Jett, John C. Martin, Peter M. Goodwin, Keller Ra, Mitchell E. Johnson, Babetta L. Marrone, and W.P. Ambrose
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Flow cytometry ,Restriction fragment ,law.invention ,chemistry.chemical_compound ,law ,Genetics ,medicine ,Deoxyribonucleases, Type II Site-Specific ,Fluorescent Dyes ,medicine.diagnostic_test ,biology ,Lasers ,DNA ,Lambda phage ,Flow Cytometry ,biology.organism_classification ,Laser ,Bacteriophage lambda ,Fluorescence ,Molecular biology ,Sizing ,Electrophoresis ,chemistry ,DNA, Viral ,Biophysics ,biology.protein - Abstract
Large, fluorescently stained restriction fragments of lambda phage DNA are sized by passing individual fragments through a focused continuous wave laser beam in an ultrasensitive flow cytometer at a rate of 60 fragments per second. The size of the fluorescence burst emitted by each stained DNA fragment, as it passes through the laser beam, is measured in one millisecond. One hundred sixty four seconds of fluorescence burst data allow linear sizing of DNA with an accuracy of better than two percent over a range of 10 to 50 kbp. This corresponds to analyzing less than 1 pg of DNA. Sizing of DNA fragments by this approach is much faster, requires much less DNA, and can potentially analyze large fragments with better resolution and accuracy than with gel-based electrophoresis.
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- 1993
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13. Sum-Frequency Generation on Dye-Coated Surfaces Using Collinear and Noncollinear Excitation Geometries
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Muenchausen, RE, primary, Nguyen, DC, additional, Keller, RA, additional, and Nogar, NS, additional
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14. Efficacy of single-dose, multilevel paravertebral nerve blockade for analgesia after thoracoscopic procedures.
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Hill SE, Keller RA, Stafford-Smith M, Grichnik K, White WD, D'Amico TA, Newman MF, Hill, Steven E, Keller, Rebecca A, Stafford-Smith, Mark, Grichnik, Katherine, White, William D, D'Amico, Thomas A, and Newman, Mark F
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- 2006
15. The bending of cell sheets - from folding to rolling
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Keller Ray and Shook David
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Biology (General) ,QH301-705.5 - Abstract
Abstract The bending of cell sheets plays a major role in multicellular embryonic morphogenesis. Recent advances are leading to a deeper understanding of how the biophysical properties and the force-producing behaviors of cells are regulated, and how these forces are integrated across cell sheets during bending. We review work that shows that the dynamic balance of apical versus basolateral cortical tension controls specific aspects of invagination of epithelial sheets, and recent evidence that tissue expansion by growth contributes to neural retinal invagination in a stem cell-derived, self-organizing system. Of special interest is the detailed analysis of the type B inversion in Volvox reported in BMC Biology by Höhn and Hallmann, as this is a system that promises to be particularly instructive in understanding morphogenesis of any monolayered spheroid system. See research article: http://www.biomedcentral.com/1741-7007/9/89
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- 2011
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16. Early development of Ensatina eschscholtzii: an amphibian with a large, yolky egg
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Collazo Andres and Keller Ray
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Evolution ,QH359-425 - Abstract
Abstract Background Comparative analyses between amphibians, concentrating on the cellular mechanisms of morphogenesis, reveal a large variability in the early developmental processes that were thought to be conserved during evolution. Increased egg size is one factor that could have a strong effect on early developmental processes such as cleavage pattern and gastrulation. Salamanders of the family Plethodontidae are particularly appropriate for such comparative studies because the species have eggs of varying size, including very large yolky eggs. Results In this paper, we describe for the first time the early development (from fertilization through neurulation) of the plethodontid salamander Ensatina eschscholtzii. This species has one of the largest eggs known for an amphibian, with a mean ± SD diameter of 6 ± 0.43 mm (range 5.3-6.9; n = 17 eggs). Cleavage is meroblastic until approximately the 16-cell stage (fourth or fifth cleavage). At the beginning of gastrulation, the blastocoel roof is one cell thick, and the dorsal lip of the blastopore forms below the equator of the embryo. The ventral lip of the blastopore forms closer to the vegetal pole, and relatively little involution occurs during gastrulation. Cell migration is visible through the transparent blastocoel roof of the gastrula. At the end of gastrulation, a small archenteron spreading dorsally from the blastopore represents the relatively small and superficial area of the egg where early embryonic axis formation occurs. The resulting pattern is similar to the embryonic disk described for one species of anuran. Conclusions Comparisons with the early development of other species of amphibians suggest that an evolutionary increase in egg size can result in predictable changes in the patterns and rate of early development, but mainly within an evolutionary lineage.
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- 2010
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17. A never-ending story: updated 3D cyber-taxonomic revision of the ant genus Zasphinctus Wheeler (Hymenoptera, Formicidae, Dorylinae) for the Afrotropical region.
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Hita Garcia F, Gómez K, Keller RA, Schurian B, and Economo EP
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The ant genus Zasphinctus are fascinating ants due to their distinctive morphology, ecology, and rarity. In this study, a comprehensive revision of Zasphinctus in the Afrotropical region is presented, through a combination of morphological examination under the light microscope and three-dimensional (3D) cyber-taxonomy based on microtomography (micro-CT). Micro-CT based 3D surface models of all species were used for virtual morphological visualisation and examination. The 3D models were virtually visualised, rotated, scaled, and dissected in order to obtain the best shape data for whole specimens or individual body parts. This approach offered a greatly improved character evaluation, allowing the development of an updated taxonomic species delimitation system for the genus. Our revision recognises eight worker-based species, of which three were previously known and five are newly described in this study. Furthermore, based on distinctive morphological differences, two species groups are also proposed. The Z.obamai group includes the species Z.obamai Hita Garcia, 2017 (Kenya), Z.lumumbai Hita Garcia & Gómez, sp. nov. (Democratic Republic of Congo), and Z.wilsoni Hita Garcia, 2017 (Mozambique) while the Z.sarowiwai group contains Z.aprilia Hita Garcia & Gómez, sp. nov. (Democratic Republic of Congo, Uganda), Z.kouakoui Hita Garcia & Gómez, sp. nov. (Ivory Coast), Z.lolae Hita Garcia & Gómez sp. nov. (Ghana), Z.ndouri Hita Garcia & Gómez, sp. nov. (Senegal), and Z.sarowiwai Hita Garcia, 2017 (Cameroon). All species are easily distinguishable through a comprehensive character matrix illustrated by numerous diagnostic illustrations, as well as a traditional dichotomous identification key., Competing Interests: The authors have declared that no competing interests exist., (Francisco Hita Garcia, Kiko Gómez, Roberto A. Keller, Bernhard Schurian, Evan P. Economo.)
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- 2025
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18. The Influence of Industry Affiliation on Randomized Controlled Trials of Platelet-Rich Plasma for Knee Osteoarthritis.
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Ta CN, Vasudevan R, Mitchell BC, Keller RA, and Kent WT
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- Humans, Treatment Outcome, Injections, Intra-Articular, Randomized Controlled Trials as Topic, Hyaluronic Acid therapeutic use, Osteoarthritis, Knee drug therapy, Platelet-Rich Plasma
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Background: Industry funding and corporate sponsorship have played a significant role in the advancement of orthopaedic research and technology. However, this relationship raises concerns for how industry association may bias research findings and influence clinical practice., Purpose: To determine whether industry affiliation plays a role in the outcomes of randomized controlled trials (RCTs) investigating platelet-rich plasma (PRP)., Study Design: Meta-analysis; Level of evidence, 2., Methods: A search of the PubMed, Cochrane, and MEDLINE databases for RCTs published between 2011 and the present comparing PRP versus hyaluronic acid, corticosteroid, or placebo for the treatment of knee osteoarthritis was performed. To determine industry affiliation, the conflict of interest, funding, and disclosure sections of publications were assessed, and all authors were assessed through the American Academy of Orthopaedic Surgeons disclosure database and the Centers for Medicare & Medicaid Services open payments database. Studies were classified as industry affiliated (IA) or non-industry affiliated (NIA). The outcomes of each study were rated as favorable, analogous, or unfavorable according to predefined criteria., Results: A total of 37 studies (6 IA and 31 NIA) were available for analysis. Overall, 19 studies (51.4%) reported PRP as favorable compared with other treatment options, while 18 studies (48.6%) showed no significant differences between PRP and other treatment methods. There was no significant difference in qualitative conclusions between the IA and NIA groups, with the IA group having 3 favorable studies and 3 analogous studies and the NIA group having 16 favorable studies and 15 analogous studies ( P = .8881). When comparing IA versus NIA studies using 6- and 12-month Western Ontario and McMaster Universities Arthritis Index and International Knee Documentation Committee scores, there were no significant differences in outcomes., Conclusion: The results of this study demonstrated that qualitative conclusions and outcome scores were found to not be associated with industry affiliation. Although the results of this study suggest that there is no influence of industry involvement on RCTs examining PRP, it is still necessary to carefully evaluate pertinent commercial affiliations when reviewing recommendations from studies before adopting new treatment approaches, such as the use of PRP for knee osteoarthritis., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: B.C.M. has received support for education from Sportstek Medical. R.A.K. has received support for education from Pinnacle, Arthrex, and Smith & Nephew; hospitality payments from Stryker and Exactech; compensation for services other than consulting from Arthrex; and a grant from DJO. W.T.K. has received consulting fees from Medical Device Business Services and KCI USA; support for education from ImpactOrtho; hospitality payments from DePuy Synthes, Stryker, and Zimmer Biomet; and speaking fees from Synthes. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
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- 2023
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19. Parallel And Divergent Morphological Adaptations Underlying The Evolution of Jumping Ability in Ants.
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Aibekova L, Keller RA, Katzke J, Allman DM, Hita-Garcia F, Labonte D, Narendra A, and Economo EP
- Abstract
Jumping is a rapid locomotory mode widespread in terrestrial organisms. However, it is a rare specialization in ants. Forward jumping has been reported within four distantly related ant genera: Gigantiops, Harpegnathos, Myrmecia , and Odontomachus . The temporal engagement of legs/body parts during jump, however, varies across these genera. It is unknown what morphological adaptations underlie such behaviors and whether jumping in ants is solely driven directly by muscle contraction or additionally relies on elastic recoil mechanism. We investigated the morphological adaptations for jumping behavior by comparing differences in the locomotory musculature between jumping and non-jumping relatives using X-ray micro-CT and 3D morphometrics. We found that the size-specific volumes of the trochanter depressor muscle ( scm6 ) of the middle and hind legs are 3-5 times larger in jumping ants, and that one coxal remotor muscle ( scm2 ) is reduced in volume in the middle and/or hind legs. Notably, the enlargement in the volume of other muscle groups is directly linked to the legs or body parts engaged during the jump. Furthermore, a direct comparison of the muscle architecture revealed two significant differences between jumping vs. non-jumping ants: First, the relative Physiological Cross-Sectional Area (PCSA) of the trochanter depressor muscles of all three legs were larger in jumping ants, except in the front legs of Odontomachus rixosus and Myrmecia nigrocincta ; second, the relative muscle fiber length was shorter in jumping ants compared to non-jumping counterparts, except in the front legs of O. rixosus and M. nigrocincta . These results suggest that the difference in relative muscle volume in jumping ants is largely invested in the area (PCSA), and not in fiber length. There was no clear difference in the pennation angle between jumping and non-jumping ants. Additionally, we report that the hind leg length relative to body length was longer in jumping ants. Based on direct comparison of the observed vs. possible work and power output during jumps, we surmise that direct muscle contractions suffice to explain jumping performance in three species, except for O. rixosus , where the lack of data on jumping performance prevents us from drawing definitive conclusions for this particular species. We suggest that increased investment in jumping-relevant musculature is a primary morphological adaptation that separates jumping from non-jumping ants. These results elucidate the common and idiosyncratic morphological changes underlying this rare adaptation in ants. まとぅみ (Okinawan language-Uchinaaguchi) (Japanese) РЕЗЮМЕ (Kazakh) ZUSAMMENFASSUNG (German)., (© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology.)
- Published
- 2023
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20. Treatment of Medial Collateral Ligament Injury During Total Knee Arthroplasty With Internal Suture Brace Augmentation: A Cadaveric and Biomechanical Study.
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Frisch NB, Keller RA, Mueller JKP, Bandi M, and Snethen KG
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- Biomechanical Phenomena, Cadaver, Humans, Knee Joint surgery, Range of Motion, Articular, Sutures, Arthroplasty, Replacement, Arthroplasty, Replacement, Knee adverse effects, Collateral Ligaments surgery, Joint Instability surgery, Medial Collateral Ligament, Knee injuries, Medial Collateral Ligament, Knee surgery
- Abstract
Intraoperative medial collateral ligament (MCL) injury during total knee arthroplasty (TKA) is a serious complication. External bracing and/or conversion to a constrained implant has previously been studied. The technique of using an internal high-strength suture brace to augment an MCL repair has been evaluated in the nonarthroplasty patient and could provide an alternate solution. The goal of this study was to determine whether MCL repair with internal suture bracing restores stability of the implanted knee joint. A robotic simulator completed laxity testing on 5 cadaveric knee specimens in 4 sequential phases: (1) intact knee, (2) after implantation with TKA, (3) after sectioning of the MCL, and (4) after MCL repair with suture brace augmentation. Laxity was compared between the different test phases throughout range of motion. Subsequently, the internal brace was tested to failure under valgus load. The MCL repair with internal bracing was effective at restoring laxity in varus-valgus, internal-external, and medial-lateral degrees of freedom through midflexion, with limited support at deeper flexion angles and in anterior-posterior laxity. Rotational laxity was not significantly different than intact knee laxity. Generally, medial-lateral translations were less and anterior-posterior translations were greater and were significantly different at 30° to 45° and 90°, respectively. The mean failure moment was 46.4±9.1 Nm, with the primary mode of failure being MCL repair. Primary MCL repair with internal bracing using a high-strength suture augment showed the potential to provide adequate stability and strength to correct MCL incompetence in TKA without the use of an external knee brace or constrained implants. [ Orthopedics . 2022;45(5):e269-e275.].
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- 2022
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21. Comparison of a Smartphone App to Manual Knee Range of Motion Measurements.
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Knapp PW, Keller RA, Mabee KA, Shi J, Pillai R, and Frisch NB
- Abstract
Background: Digital technology has emerged as a useful tool for preoperative and postoperative patient engagement and for remote patient monitoring. Smartphones are equipped with motion-sensing technology, and apps can be designed which use these features to create a simple method for measuring range of motion. The purpose of this study was to determine the accuracy of digital technology in assessing knee range of motion using a smartphone app, compared to traditional goniometric measurements in an office setting., Methods: Fifty-three (53) patients in a clinical practice were enrolled between October 2019 and March 2020. Three separate measurements were taken during the patient encounter: (1) the surgeon, (2) the app, and (3) the physical therapist. Intraclass correlations were computed to assess the agreement between (1) the surgeon and app and (2) that between the physical therapist and surgeon., Results: When measuring flexion, the correlation between either the surgeon or therapist with the app was good, whereas the comparison between the surgeon and therapist was moderate. All extension measurement comparisons, between the app, surgeon, and therapist, showed moderate correlation. Limits of agreements showed that 80% of the difference between surgeon and app is within 10 degrees for extension and 11 degrees for flexion. Body mass index did not affect the accuracy of the measurements., Conclusion: Digital app measurements were comparable to measurements made by either a surgeon or physical therapist with a manual goniometer in the clinical setting and may be beneficial for measuring and monitoring patients' range of motion remotely., (© 2021 Published by Elsevier Inc. on behalf of The American Association of Hip and Knee Surgeons.)
- Published
- 2022
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22. Ulnar Neuritis and Its Affect on Outcomes of Elbow Ulnar Collateral Ligament Reconstruction.
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De Giacomo AF, Keller RA, Banffy M, and ElAttrache NS
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- Cohort Studies, Elbow, Humans, Return to Sport, Baseball, Collateral Ligament, Ulnar surgery, Collateral Ligaments surgery, Elbow Joint surgery, Ulnar Collateral Ligament Reconstruction, Ulnar Neuropathies surgery
- Abstract
Background: No study has specifically evaluated how ulnar neuritis and ulnar nerve transposition affect outcomes in baseball players undergoing ulnar collateral ligament (UCL) reconstruction (UCLR)., Purpose: To evaluate the effects of ulnar neuritis and ulnar nerve transposition in baseball pitchers undergoing UCLR in regard to return to sport, time to return to sport, and need for revision or additional surgery., Study Design: Cohort study; Level of evidence, 3., Methods: At a single institution, all consecutive baseball pitchers undergoing UCLR between 2002 and 2015 were identified. Ulnar neuritis was diagnosed preoperatively by the following criteria: ulnar nerve symptoms, Tinel sign at the elbow, symptomatic subluxation, and numbness/paresthesia in an ulnar nerve distribution of the hand. The primary outcome of the study was return to sport. The secondary outcomes of the study were time to return to sport, length of playing career, and revision or additional surgery., Results: A total of 578 UCLRs were performed in baseball players; of these, 500 UCLRs were performed in pitchers. Ulnar neuritis was diagnosed in 97 (19.4%) baseball pitchers presenting with UCL injury. There were no significant differences in patient characteristics or surgical techniques performed for reconstruction between baseball pitchers with and without ulnar neuritis. In review of injury characteristics, ulnar neuritis was significantly more likely to be diagnosed in pitchers with an acute onset of UCL injury ( P = .03). Transposition of the ulnar nerve was more commonly performed in players with ulnar neuritis (47%) versus those without ulnar neuritis (10%; P = .0001). The players who had ulnar neuritis and underwent UCLR had a significantly lower odds of returning to sport (odds ratio, 0.45; P = .04); however, no significant difference was found for time to return to sport and length of playing career for those with and without ulnar neuritis ( P = .38 and .51, respectively)., Conclusion: The study suggests that ulnar neuritis, when present preoperatively in baseball pitchers undergoing UCLR, may adversely affect their ability to return to sport, whereas ulnar nerve transposition at the time of UCLR does not alter the ability to return to sport.
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- 2022
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23. Quantifying Patient Engagement in Total Joint Arthroplasty Using Digital Application-Based Technology.
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Knapp PW, Keller RA, Mabee KA, Pillai R, and Frisch NB
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- Humans, Middle Aged, Patient Participation, Patient Satisfaction, Technology, Arthroplasty, Replacement, Hip, Arthroplasty, Replacement, Knee
- Abstract
Background: Digital patient engagement has been suggested as a mean to increase patient activation and patient satisfaction after total joint arthroplasty. The purpose of this study was to assess patient engagement with application-based educational tools and to explore what content was most useful to patients in the perioperative period surrounding total hip arthroplasty (THA) and total knee arthroplasty (TKA), respectively., Methods: Patients undergoing THA and TKA between October 2017 and January 2020 were enrolled to use an application-based digital technology. The App provides comprehensive patient education using a series of modules delivered at set intervals preoperatively and postoperatively. Patient engagement was defined as patients viewing at least one time the modules that were sent, or marking them as completed. Patient satisfaction was assessed using an in-application survey., Results: Complete data were available on 207 patients of which 95 (46%) underwent THA and 112 (54%) underwent TKA. The average age was 60 years. 54% with patients invited to the program completed registration. An average compliance rate of 48% (41 modules engaged out of 83) was observed. Of all modules completed, the top three most popular categories included physical therapy/exercise videos, health literacy, and anxiety/stress/pain management. The least viewed category was nutrition planning and education., Conclusion: When presented educational material related to THA and TKA, patients had a high rate of compliance. Digital technology platforms provide a scalable, meaningful approach to engaging patients throughout the continuum of joint replacement care and may serve as a cost-effective adjunct to traditional methods., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2021
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24. The loss of flight in ant workers enabled an evolutionary redesign of the thorax for ground labour.
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Peeters C, Keller RA, Khalife A, Fischer G, Katzke J, Blanke A, and Economo EP
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Background: Explanations for the ecological dominance of ants generally focus on the benefits of division of labour and cooperation during foraging. However, the principal innovation of ants relative to their wasp ancestors was the evolution of a new phenotype: a wingless worker caste optimized for ground labour. Ant workers are famous for their ability to lift and carry heavy loads, but we know surprisingly little about the morphological basis of their strength. Here we examine the consequences of the universal loss of flight in ant workers on skeletomuscular adaptations in the thorax for enhanced foraging on six legs., Results: Using X-ray microcomputed tomography and 3D segmentation, we compared winged queens and wingless workers in Euponera sikorae (subfamily Ponerinae) and Cataglyphis savignyi (subfamily Formicinae). Workers are characterized by five major changes to their thorax: i) fusion of the articulated flight thorax (queens) into a rigid box optimized to support the muscles that operate the head, legs and abdomen, ii) redesign of internal cuticular structures for better bracing and muscle attachment, iii) substantial enlargement of the neck muscles for suspending and moving the head, iv) lengthening of the external trochanter muscles, predominant for the leg actions that lift the body off the ground, v) modified angle of the petiole muscles that are key for flexion of the abdomen. We measured volumes and pennation angles for a few key muscles to assess their increased efficacy. Our comparisons of additional workers across five genera in subfamilies Dorylinae and Myrmicinae show these modifications in the wingless thorax to be consistent. In contrast, a mutillid wasp showed a different pattern of muscle adaptations resulting from the lack of wing muscles., Conclusions: Rather than simply a subtraction of costly flight muscles, we propose the ant worker thorax evolved into a power core underlying stronger mandibles, legs, and sting. This contrasts with solitary flightless insects where the lack of central place foraging generated distinct selective pressures for rearranging the thorax. Stronger emphasis is needed on morphological innovations of social insects to further our understanding of the evolution of social behaviours., Competing Interests: Competing interestsWe have no competing interests, (© The Author(s) 2020.)
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- 2020
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25. Distal leg structures of the Aculeata (Hymenoptera): A comparative evolutionary study of Sceliphron (Sphecidae) and Formica (Formicidae).
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Beutel RG, Richter A, Keller RA, Hita Garcia F, Matsumura Y, Economo EP, and Gorb SN
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- Animals, Ants ultrastructure, Bees ultrastructure, Female, Imaging, Three-Dimensional, Phylogeny, Ants anatomy & histology, Bees anatomy & histology, Biological Evolution, Extremities anatomy & histology
- Abstract
The distal parts of the legs of Sceliphron caementarium (Sphecidae) and Formica rufa (Formicidae) are documented and discussed with respect to phylogenetic and functional aspects. The prolegs of Hymenoptera offer an array of evolutionary novelties, mainly linked with two functional syndromes, walking efficiently on different substrates and cleaning the body surface. The protibial-probasitarsomeral cleaning device is almost always well-developed. A complex evolutionary innovation is a triple set of tarsal and pretarsal attachment devices, including tarsal plantulae, probasitarsomeral spatulate setae, and an arolium with an internal spring-like arcus, a dorsal manubrium, and a ventral planta. The probasitarsal adhesive sole and a complex arolium are almost always preserved, whereas the plantulae are often missing. Sceliphron has retained most hymenopteran ground plan features of the legs, and also Formica, even though the adhesive apparatus of Formicidae shows some modifications, likely linked to ground-oriented habits of most ants. Plantulae are always absent in extant ants, and the arolium is often reduced in size, and sometimes vestigial. The arolium contains resilin in both examined species. Additionally, resilin enriched regions are also present in the antenna cleaners of both species, although they differ in which of the involved structures is more flexible, the calcar in Sceliphron and the basitarsal comb in Formica. Functionally, the hymenopteran distal leg combines (a) interlocking mechanisms (claws, spine-like setae) and (b) adhesion mechanisms (plantulae, arolium). On rough substrate, claws and spine-like setae interlock with asperities and secure a firm grip, whereas the unfolding arolium generates adhesive contact on smooth surfaces. Differences of the folded arolium of Sceliphron and Formica probably correlate with differences in the mechanism of folding/unfolding., (© 2020 The Authors. Journal of Morphology published by Wiley Periodicals, Inc.)
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- 2020
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26. Current practice: postoperative and return to play trends after ACL reconstruction by fellowship-trained sports surgeons.
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Marshall NE, Keller RA, Dines J, Bush-Joseph C, and Limpisvasti O
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- Anterior Cruciate Ligament Reconstruction statistics & numerical data, Anterior Cruciate Ligament Reconstruction trends, Cross-Sectional Studies, Fellowships and Scholarships, Humans, Motion Therapy, Continuous Passive statistics & numerical data, Postoperative Care, Return to Sport statistics & numerical data, Surveys and Questionnaires statistics & numerical data, Time Factors, Anterior Cruciate Ligament Reconstruction methods, Braces statistics & numerical data, Return to Sport trends, Sports Medicine statistics & numerical data, Weight-Bearing
- Abstract
Purpose: Advances in anterior cruciate ligament (ACL) reconstruction have allowed for many progressions in postoperative management. However, there is no standardized protocol for immediate postoperative management or return to play. Our objective was to evaluate current trends in immediate postoperative and return to sport practices after ACL reconstruction., Level of Evidence: Cross sectional study, Level IV., Methods: Surveys were obtained from four large sports fellowship alumni networks. Demographics included years of practice and ACLs performed per year. Postoperative questions included weight bearing status, brace use and continuous passive motion (CPM) use. Return to play included time for return, brace use and metrics used for clearance to sport., Results: A total of 143 surveys were completed (32% response rate). Average years in practice were 15.1 years. Average ACL reconstructions performed per year was 20-50 in 44% and 50-100 in 29%. 26% used CPM in all patients, 8% if concomitant meniscal repair and 66% never. Bracing after surgery was used in 84% and 48% after return to play. Return to play was allowed at 6-9 months in 67% and overall 94% from 6 to 12 months. No consensus on return to play metrics was used, with the hop test being most important followed by specific time point after surgery., Conclusion: Immediate weight bearing after surgery is commonplace with intermittent CPM use. Bracing is common postoperatively and half the time with return to play. Return to play is typically allowed after at least 6 months with no consensus on return to sport metrics. Years after fellowship and ACLs performed yearly had no correlation with postoperative practices.
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- 2019
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27. The cephalic anatomy of workers of the ant species Wasmannia affinis (Formicidae, Hymenoptera, Insecta) and its evolutionary implications.
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Richter A, Keller RA, Rosumek FB, Economo EP, Hita Garcia F, and Beutel RG
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- Animals, Ants ultrastructure, Head anatomy & histology, Microscopy, Electron, Scanning, Tomography, X-Ray Computed, Ants anatomy & histology, Biological Evolution
- Abstract
Despite the ecological significance of ants and the intensive research attention they have received, thorough treatments of the anatomy and functional morphology are still scarce. In this study we document the head morphology of workers of the myrmicine Wasmannia affinis with optical microscopy, μ-computed tomography, scanning electron microscopy, and 3D reconstruction, providing the first complete anatomical treatment of an ant head with a broad array of modern techniques. We discuss the potential of the applied methods to generate detailed and well-documented morphological data sets with increased efficiency. We also address homology problems, particularly in the context of the cephalic digestive tract. According to our analyses the "pharynx" of previous ant studies is homologous to the prepharynx of other insects. We also discuss the phylogenetic potential and functional significance of the observed characters, with internal features such as tentorium and musculature discussed for the first time. Our investigation underlines that detailed anatomical data for Formicidae are still very fragmentary, which in turn limits our understanding of the major design elements underlying the ant bauplan. We attempt to provide a template for further anatomical studies, which will help to understand the evolution of this fascinating group on the phenotypic level., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
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- 2019
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28. Posterior capsule injection of local anesthetic for post-operative pain control after ACL reconstruction: a prospective, randomized trial.
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Keller RA, Birns ME, Cady AC, Limpisvasti O, and Banffy MB
- Subjects
- Adult, Analgesics, Opioid therapeutic use, Arthroscopy, Bupivacaine administration & dosage, Female, Femoral Nerve, Humans, Joint Capsule, Knee Joint, Male, Middle Aged, Prospective Studies, Visual Analog Scale, Anesthetics, Local administration & dosage, Anterior Cruciate Ligament Reconstruction, Injections, Intra-Articular, Nerve Block, Pain, Postoperative prevention & control
- Abstract
Purpose: Alternative modalities to optimize pain control after anterior cruciate ligament reconstruction (ACLR) are continually being explored. The purpose of this study was to compare femoral nerve block (FNB) only vs FNB with posterior capsule injection (PCI) of the knee for pain control in patients undergoing ACLR., Methods: Patients undergoing primary ACLR were randomized to receive either FNB only or FNB with PCI. Following surgery, patient's pain was evaluated in the postoperative care unit (PACU) and at home for 4 days. Pain levels were measured via visual analog scale (VAS) and calculating opioid consumption. Outcomes of interest included postoperative pain levels and opioid consumption., Results: A total of 42 patients were evaluated, with 21 patients randomized to each study arm. Outcomes showed significant pain reduction in both anterior and posterior knee VAS scores in the PACU in those that received PCI (anterior VAS: 39.6 vs 21.3 (SD = 12.9), p < 0.01; posterior VAS: 25.4 vs 15.3 (SD = 8.05), p = 0.01). Moreover, the PCI group also showed significantly less opioid consumption compared to FNB only (23.5 vs 17.4 pills, p = 0.03). There were no differences found in pain scores between groups in home VAS sores., Conclusions: These finding suggest the use of arthroscopically assisted injection of local anesthetic to the posterior capsule of the knee significantly reduces early post-operative pain and dramatically reduces the number of opoid medication taken after ACLR., Level of Evidence: Prospective, randomized, control trial, Level I.
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- 2019
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29. Medial Elbow Pain During the Return-to-Throwing Period After Ulnar Collateral Ligament Reconstruction in Pitchers.
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Keller RA, Marshall NE, Limpisvasti O, DeGiacomo AF, Banffy M, and ElAttrache NS
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Background: Ulnar collateral ligament reconstruction (UCLR) is common in the sport of baseball, particularly among pitchers. Postoperative return-to-sport protocols have many players beginning to throw at 4 to 5 months and returning to full competition between 12 and 16 months after surgery. Medial elbow pain during the return-to-throwing period often occurs and can be difficult to manage., Purpose: To evaluate the incidence of medial elbow pain and associations with outcomes and revision surgery during the return-to-throwing period after UCLR., Study Design: Case-control study; Level of evidence, 3., Methods: Between the years of 2002 and 2014, all pitchers who underwent UCLR at a single institution were identified. Charts were reviewed for incidence of medial elbow pain during return to throwing, return to sport, and subsequent operative interventions, including revision ulnar collateral ligament surgery., Results: Of a total of 616 pitchers who underwent UCLR during the study period, 317 were included in this study. Medial elbow pain was experienced by 45.1% (143 of 317), with a mean time of complaint of 9.75 months after surgery. The groups with and without pain did not differ statistically with regard to age (pain, 20.6 years; no pain, 20.9 years) or level of competition. Of those who experienced medial elbow pain, 10.5% did not return to sport; 5.6% underwent revision UCLR; and 19.6% underwent other operative procedures at the elbow. Among those who did not experience medial elbow pain when returning to throw, 8.7% did not return to sport, with only 1.7% undergoing revision UCLR and 6.9% undergoing other operative elbow procedures., Conclusion: Of the pitchers evaluated in the study, approximately half reported pain during the return-to-throwing phase after UCLR. Those who experienced medial elbow pain had a higher rate of subsequent surgical intervention., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: R.A.K. has received educational support from Zimmer Biomet, Arthrex, Smith & Nephew, and DJO. O.L. is a consultant for Arthrex and receives royalties from ConMed Linvatec. A.F.D. has received educational support from Arthrex, Smith & Nephew, and DJO. M.B. is a paid speaker/presenter for Arthrex, has received educational support from Mako Surgical, and is a consultant for Stryker. N.S.E. receives royalties from Arthrex and Wolters Kluwer Health–Lippincott Williams & Wilkins and is a paid speaker/presenter for Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
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- 2018
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30. Pitching Performance After Ulnar Collateral Ligament Reconstruction at a Single Institution in Major League Baseball Pitchers.
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Marshall NE, Keller RA, Limpisvasti O, and ElAttrache NS
- Subjects
- Adult, Cohort Studies, Humans, Male, Young Adult, Baseball statistics & numerical data, Return to Sport statistics & numerical data, Ulnar Collateral Ligament Reconstruction statistics & numerical data
- Abstract
Background: Ulnar collateral ligament (UCL) reconstruction (UCLR) has shown reliable rates of return to play, with conflicting results on pitching performance after players' return., Purpose: To evaluate Major League Baseball (MLB) pitching performance before and after UCLR performed at a single institution., Study Design: Cohort study; Level of evidence, 3., Methods: MLB pitchers (minor league players were excluded) who underwent UCLR at our institution between 2002 and 2016 were identified. Player information and return to play were determined including pitching level (MLB vs minor league) and total number of years played after surgery. Pitching performance statistics were evaluated for 3 years before surgery and for 3 years after returning to play including earned run average (ERA), walks plus hits per inning pitched (WHIP), innings pitched, wins above replacement, runs above replacement, and pitch velocity., Results: A total of 54 MLB pitchers were identified, with 46 primary and 8 revision reconstructions. The mean time to return to play was 13.8 months (primary reconstruction: 13.7 months). The majority returned to play with a 94% return rate (primary reconstruction: 96%), and 80% returned to MLB play (primary reconstruction: 82%). Three primary reconstructions required revision surgery. Pitchers played a mean of 3.2 years in MLB and 4.6 years total after surgery (39% still playing). Pitching workload and performance were maintained or improved after surgery. The preoperative ERA was 4.63 versus 4.13 after returning to play ( P = .268). Fastball velocity ( P = .032), ERA ( P = .003), and WHIP ( P = .001) worsened the first year after surgery and then improved the second year (ERA: 4.63 to 4.06 [ P = .380]; WHIP: 1.35 to 1.32 [ P = .221]; fastball velocity: 91.3 to 91.9 mph [ P = .097]). Compared with a matched control group, pitchers who had UCLR showed improvements or maintained performance after reconstruction including improved ERA ( P = .007), WHIP ( P = .025), and fastball velocity ( P = .006)., Conclusion: MLB players experienced a high rate of return to play and previous level of play after UCLR. Pitching workload was maintained after returning to play. Pitching performance initially decreased the first year after returning and then improved or reverted to previous levels after the first year from UCLR.
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- 2018
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31. Skeletomuscular adaptations of head and legs of Melissotarsus ants for tunnelling through living wood.
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Khalife A, Keller RA, Billen J, Hita Garcia F, Economo EP, and Peeters C
- Abstract
Background: While thousands of ant species are arboreal, very few are able to chew and tunnel through living wood. Ants of the genus Melissotarsus (subfamily Myrmicinae) inhabit tunnel systems excavated under the bark of living trees, where they keep large numbers of symbiotic armoured scale insects (family Diaspididae). Construction of these tunnels by chewing through healthy wood requires tremendous power, but the adaptations that give Melissotarsus these abilities are unclear. Here, we investigate the morphology of the musculoskeletal system of Melissotarsus using histology, scanning electron microscopy, X-ray spectrometry, X-ray microcomputed tomography (micro-CT), and 3D modelling., Results: Both the head and legs of Melissotarsus workers contain novel skeletomuscular adaptations to increase their ability to tunnel through living wood. The head is greatly enlarged dorsoventrally, with large mandibular closer muscles occupying most of the dorsal half of the head cavity, while ventrally-located opener muscles are also exceptionally large. This differs from the strong closing: opening asymmetry typical of most mandibulated animals, where closing the mandibles requires more force than opening. Furthermore, the mandibles are short and cone-shaped with a wide articulatory base that concentrates the force generated by the muscles towards the tips. The increased distance between the axis of mandibular rotation and the points of muscle insertion provides a mechanical advantage that amplifies the force from the closer and opener muscles. We suggest that the uncommonly strong opening action is required to move away crushed plant tissues during tunnelling and allow a steady forward motion. X-ray spectrometry showed that the tip of the mandibles is reinforced with zinc. Workers in this genus have aberrant legs, including mid- and hindlegs with hypertrophied coxae and stout basitarsi equipped with peg-like setae, and midleg femura pointed upward and close to the body. This unusual design famously prevents them from standing and walking on a normal two-dimensional surface. We reinterpret these unique traits as modifications to brace the body during tunnelling rather than locomotion per se., Conclusions: Melissotarsus represents an extraordinary case study of how the adaptation to - and indeed engineering of - a novel ecological niche can lead to the evolutionary redesign of core biomechanical systems., Competing Interests: Not applicable.Not applicable.The authors declare that they have no competing interests.Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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- 2018
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32. The utility of botulinum toxin A in the repair of distal biceps tendon ruptures.
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Khalil LS, Keller RA, Mehran N, Marshall NE, Okoroha K, Frisch NB, and DeSilva SP
- Subjects
- Adult, Chemotherapy, Adjuvant, Combined Modality Therapy, Debridement, Disability Evaluation, Drug Evaluation, Follow-Up Studies, Humans, Male, Middle Aged, Postoperative Complications etiology, Retrospective Studies, Rupture surgery, Suture Anchors, Tendon Injuries surgery, Transplantation, Autologous, Treatment Outcome, Botulinum Toxins, Type A therapeutic use, Tendon Injuries drug therapy
- Abstract
Purpose: The purpose of our study is to report the outcomes and complications in patients who underwent distal biceps tendon repair with the use of Botulinum toxin A (BoNT-A) as an adjunct to surgery., Methods: A retrospective review of 14 patients who underwent 15 distal biceps tendon repairs was performed. All repaired tendons had their correlating muscle bellies injected intraoperatively with a mixture of 100U of BoNT-A and 10 ml of normal saline. Each patient was evaluated for surgical and post-operative complications and followed with Disabilities of the Arm, Shoulder and Hand (DASH) Disability Scores., Results: The cohort was exclusively male, 14/14 (100%). The mean age at procedure was 52.1 years (range: 29-65 years). Types of injuries repaired included: 12 acute biceps tendon ruptures, one chronic partial (> 50% of tendon) biceps tear, and two chronic biceps ruptures. Average final follow-up was 32.9 months (SD: 19.6; range: 7.07-61.72). Average time to repair of chronic injury was 5.75 months (range: 2-12 months). There were no intraoperative complications, and all patients were discharged home on the day of surgery. Average DASH score at latest follow-up was 4.9 (range: 0.0-12.5). All patients had return of function of paralyzed muscle prior to final follow-up. One patient required an incision and drainage for a deep infection 1 week post-operatively, without any further complications. Another patient required operative removal of heterotopic ossification located around the tendon fixation site, which was the result of a superficial infection treated with antibiotics 2 weeks post-operatively. This patient later healed with improvement in supination/pronation range-of-motion and no further complications., Conclusions: Injection of BoNT-A is safe and effective to protect distal biceps tendon repair during the early phases of bone-tendon healing., Clinical Relevance: BoNT-A may is safe and effective to protect distal biceps tendon repair. The utility of BoNT-A as an adjunct to surgical repair may be applicable to acute or chronic tears as well as repairs in the non-compliant patient without decreases in functional scores after return of function of the biceps muscle., Level of Evidence: Level 4.
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- 2018
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33. Glenohumeral Internal Rotation Deficit and Risk of Upper Extremity Injury in Overhead Athletes: A Meta-Analysis and Systematic Review.
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Keller RA, De Giacomo AF, Neumann JA, Limpisvasti O, and Tibone JE
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- Adaptation, Physiological, Female, Humans, Male, Range of Motion, Articular, Risk Factors, Rotation, Young Adult, Athletic Injuries physiopathology, Elbow physiopathology, Shoulder Injuries, Shoulder Joint physiopathology, Elbow Injuries
- Abstract
Context: Current perception dictates that glenohumeral internal rotation deficit (GIRD) is a chronic adaptation that leads to an increased risk of pathologic conditions in the dominant shoulder or elbow of overhead athletes., Objective: To determine whether adaptations in glenohumeral range of motion in overhead athletes lead to injuries of the upper extremity, specifically in the shoulder or elbow., Data Sources: An electronic database search was performed using Medline, Embase, and SportDiscus from 1950 to 2016. The following keywords were used: GIRD, glenohumeral internal rotation deficit, glenohumeral deficit, shoulder, sport, injury, shoulder joint, baseball, football, racquet sports, volleyball, javelin, cricket, athletic injuries, handball, lacrosse, water polo, hammer throw, and throwing injury., Study Selection: Seventeen studies met the inclusion criteria for this systematic review. Of those 17 studies, 10 included specific range of motion measurements required for inclusion in the meta-analysis., Study Design: Systematic review and meta-analysis., Level of Evidence: Level 4., Data Extraction: Data on demographics and methodology as well as shoulder range of motion in various planes were collected when possible. The primary outcome of interest was upper extremity injury, specifically shoulder or elbow injury., Results: The systematic review included 2195 athletes (1889 males, 306 females) with a mean age of 20.8 years. Shoulders with GIRD favored an upper extremity injury, with a mean difference of 3.11° (95% CI, -0.13° to 6.36°; P = 0.06). Shoulder total range of motion suggested increased motion (mean difference, 2.97°) correlated with no injury ( P = 0.11), and less total motion (mean difference, 1.95°) favored injury ( P = 0.14). External rotational gain also favored injury, with a mean difference of 1.93° ( P = 0.07)., Conclusion: The pooled results of this systematic review and meta-analysis did not reach statistical significance for any shoulder motion measurement and its correlation to shoulder or elbow injury. Results, though not reaching significance, favored injury in overhead athletes with GIRD, as well as rotational loss and external rotational gain.
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- 2018
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34. Deep Venous Thrombosis Prophylaxis in Anterior Cruciate Ligament Reconstructive Surgery: What Is the Current State of Practice?
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Keller RA, Moutzouros V, Dines JS, Bush-Joseph CA, and Limpisvasti O
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- Anterior Cruciate Ligament Injuries surgery, Aspirin administration & dosage, Aspirin therapeutic use, Early Ambulation, Fibrinolytic Agents administration & dosage, Fibrinolytic Agents therapeutic use, Health Surveys, Humans, Motion Therapy, Continuous Passive, Risk Factors, Stockings, Compression, United States, Anterior Cruciate Ligament Reconstruction, Health Knowledge, Attitudes, Practice, Orthopedic Surgeons, Postoperative Complications prevention & control, Venous Thrombosis prevention & control
- Abstract
Background: Venous thromboembolism (VTE) is a significant perioperative risk with many common orthopaedic procedures. Currently, there is no standardized recommendation for the use of VTE prophylaxis during anterior cruciate ligament (ACL) reconstruction. This study sought to evaluate the current prophylactic practices of fellowship-trained sports medicine orthopaedic surgeons in the United States., Hypothesis: Very few surgeons use perioperative VTE prophylaxis for ACL reconstructive surgery., Study Design: Survey., Methods: Surveys were emailed to the alumni networks of 4 large ACGME-accredited sports medicine fellowship programs. Questions were focused on their current use of chemical and nonchemical VTE prophylaxis., Results: Surveys were completed by 142 surgeons in the United States, yielding a response rate of 32%. Of those who responded, 50.7% stated that they routinely use chemical prophylaxis, with 95.5% of those using aspirin (acetylsalicylic acid [ASA]). There was no standardized dosing protocol, with respondents using ASA 325 mg once (46%) or twice daily (26%) or ASA 81 mg once (18%) or twice (10%) daily. The most common reason for not including chemical prophylaxis within the reconstruction procedure was that it is unnecessary given the low risk of VTE. Physicians also based their prophylaxis regimen more on their own clinical experience than concern for litigation., Conclusion: Half of all sports medicine fellowship-trained surgeons surveyed routinely use chemical VTE prophylaxis after ACL reconstruction, with more than 90% of those using ASA. Of those using ASA, there was no prevailing dosing protocol. For those not using chemical prophylaxis, the most important reason was that it was felt to be unnecessary due to the risks outweighing the benefits. Those who do not regularly use chemical prophylaxis would be willing to, however, if a patient had a personal or family history of clotting disorder or is currently on birth control. Additionally, clinical experience was the primary driver for a current prophylaxis protocol., Clinical Relevance: This survey study evaluating the use of VTE prophylaxis with ACL reconstruction lends clinical insight to the current practice of a large, geographically diverse group of fellowship-trained sports medicine orthopaedic surgeons in the United States.
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- 2018
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35. Single-Shot Femoral Nerve Block Does Not Cause Long-Term Strength and Functional Deficits Following Anterior Cruciate Ligament Reconstruction.
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Okoroha KR, Khalil L, Jung EK, Keller RA, Marshall NE, Abouljoud M, Chan D, and Moutzouros V
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- Adult, Anesthesia, Local methods, Anterior Cruciate Ligament Injuries surgery, Female, Follow-Up Studies, Humans, Male, Muscle Strength drug effects, Muscle Strength physiology, Nerve Block methods, Prospective Studies, Anesthesia, Local adverse effects, Anterior Cruciate Ligament Reconstruction adverse effects, Femoral Nerve drug effects, Nerve Block adverse effects, Pain, Postoperative therapy
- Abstract
Purpose: To determine if patients treated with a single-shot femoral nerve block have strength and functional deficits at 9-month follow-up., Methods: Forty-three patients who underwent primary anterior cruciate ligament reconstructions were randomized to receive either a preoperative single-shot femoral nerve block or local infiltration anesthesia for primary pain control. All patients underwent a standardized comprehensive rehabilitation program postoperatively. Isokinetic strength and function was tested using a Biodex machine at 9 months or more postoperatively comparing the operative and nonoperative extremity., Results: No significant difference in strength was found at an average of 10.6 months postoperatively (range, 9-15 months) between the femoral nerve block and control groups. In comparing strength deficits, we found no difference in slow isokinetic extension strength (22.4% vs 27.8%, P = .51), fast isokinetic extension strength (18.5% vs 12.5%, P = .41), slow isokinetic flexion strength (11.0% vs 15.1%, P = .55), and fast isokinetic flexion strength (8.2% vs 4.9%, P = .56) in the femoral nerve block versus control groups, respectively. In terms of functional outcomes, there also was no difference in deficits for single-leg hop distance (P = .12), timed single-leg hop (P = .74), and single-leg triple hop distance (P = .94). Maximal strength noted to be within 15% of the contralateral limb was achieved in 40% of patients and maximal function in 63% of patients at an average of 10.6 months postoperatively. A 13% complication rate was found in patients who received a femoral nerve block (1 with prolonged quadriceps inhibition and 2 with prolonged sensory disturbances)., Conclusions: Our study found a 13% motor/sensory complication rate in patients who underwent femoral nerve block for pain control after anterior cruciate ligament reconstruction. Although these deficits may persist, they are not permanent and are not different when compared with controls at 9-month follow-up. However, maximal strength and function are not fully restored at normal return to play time and rehabilitation should continue long term to maximize recovery., Level of Evidence: Level I, prospective randomized trial., (Copyright © 2017 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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36. Return to play after shoulder instability in National Football League athletes.
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Okoroha KR, Taylor KA, Marshall NE, Keller RA, Fidai M, Mahan MC, Varma V, and Moutzouros V
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- Adult, Humans, Joint Instability surgery, Male, Occupational Injuries surgery, Recurrence, Shoulder Dislocation surgery, Shoulder Injuries surgery, Time Factors, Young Adult, Conservative Treatment, Football injuries, Joint Instability therapy, Occupational Injuries therapy, Return to Sport, Shoulder Dislocation therapy, Shoulder Injuries therapy
- Abstract
Hypothesis: We hypothesized that National Football League (NFL) players sustaining a shoulder destabilizing injury could return to play (RTP) successfully at a high rate regardless of treatment type., Methods: We identified and evaluated 83 NFL players who sustained an in-season shoulder instability event while playing in the NFL. NFL RTP, incidence of surgery, time to RTP, recurrent instability events, seasons/games played after the injury, and demographic data were collected. Overall RTP was determined, and players who did and did not undergo operative repair were compared., Results: Ninety-two percent of NFL players returned to NFL regular season play at a median of 0.0 weeks in those sustaining a shoulder subluxation and 3.0 weeks in those sustaining a dislocation who did not undergo surgical repair (P = .029). Players who underwent operative repair returned to play at a median of 39.3 weeks. Forty-seven percent of players had a recurrent instability event. For players who were able to RTP, those who underwent surgical repair (31%) had a lower recurrence rate (26% vs. 55%, P = .021) and longer interval between a recurrent instability event after RTP (14.7 vs. 2.5 weeks, P = .050)., Conclusion: There is a high rate of RTP after shoulder instability events in NFL players. Players who sustain shoulder subluxations RTP faster but are more likely to experience recurrent instability than those with shoulder dislocations. Surgical stabilization of the shoulder after an instability event decreases the chances of a second instability event and affords a player a greater interval between the initial injury and a recurrent event., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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37. Return to Play After Revision Anterior Cruciate Ligament Reconstruction in National Football League Players.
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Okoroha KR, Kadri O, Keller RA, Marshall N, Cizmic Z, and Moutzouros V
- Abstract
Background: National Football League (NFL) players who undergo anterior cruciate ligament (ACL) reconstruction have been shown to have a lower return to play (RTP) than previously expected. However, RTP in the NFL after revision ACL reconstruction (RACLR) is not well defined., Purpose/hypothesis: The purpose of this study is to determine the RTP of NFL players after RACLR and evaluate factors that predict RTP. Our hypothesis was that more experienced and established players would be more likely to RTP after RACLR., Study Design: Cohort study; Level of evidence, 3., Methods: A total of 24 NFL players who underwent RACLR between 2007 and 2014 were reviewed and evaluated. Return to NFL play, time to return, seasons and games played prior to and after revision surgery, draft status, and demographic data were collected. Overall RTP was determined, and players who did RTP were compared with those unable to RTP. Data were also compared with control players matched for age, position, size, and experience., Results: After RACLR, 79% (19/24) of NFL players returned to NFL regular-season play at an average of 12.6 months. All players who were drafted in the first 4 rounds, played in at least 55 games, or played 4 seasons of NFL play prior to injury were able to RTP. Players drafted in the first 4 rounds of the NFL draft were more likely to RTP than those who were not (odds ratio, 0.1; 95% CI, 0.01-1.00; P = .05). Those who returned to NFL play played in significantly less games and seasons after their injury than before ( P = .01 and P = .01, respectively). However, these values did not differ when compared with matched controls ( P = .67 and P = .33)., Conclusion: NFL players who RTP after RACLR do so at a similar rate but prolonged time period compared with after primary ACL reconstruction. Athletes who were drafted in earlier rounds were more likely to RTP than those who were not. Additionally, player experience prior to injury is an important factor when predicting RTP after RACLR., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution.
- Published
- 2017
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38. Relative individual workload changes may be a risk factor for rerupture of ulnar collateral ligament reconstruction.
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Keller RA, Mehran N, Khalil LS, Ahmad CS, and ElAttrache N
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- Adult, Collateral Ligament, Ulnar surgery, Female, Humans, Male, Reoperation, Risk Factors, Young Adult, Elbow Injuries, Baseball injuries, Collateral Ligament, Ulnar injuries, Elbow Joint surgery, Physical Endurance physiology, Ulnar Collateral Ligament Reconstruction methods
- Abstract
Background: With an increasing number of Major League Baseball (MLB) players undergoing ulnar collateral ligament (UCL) reconstruction, there remains limited literature on appropriate post-reconstruction workload management to limit the risk of reinjury., Methods: A total of 28 MLB pitchers who underwent primary UCL reconstruction surgery and subsequently required revision reconstruction were identified and compared with 137 MLB pitchers who underwent primary reconstruction but did not later require revision surgery. Games pitched, pitch counts, and innings pitched were evaluated and compared 3 years before and after primary reconstruction. Results were then compared between groups., Results: Pitchers who later required revision increased their games pitched by 14.1% after reconstruction whereas the no-revision group pitched 13.6% fewer games than before reconstruction (P < .01). Inning workload was reduced by 9.8% after surgery (89.8 innings after vs 99.6 innings before) for the revision group compared with the no-revision group, which threw 26% fewer innings after surgery (86.3 innings after vs 116.7 innings before) (P = .05). In addition, the revision group pitched 6.6% more pitches after reconstruction, 1138.9 pitches, compared with before reconstruction, 1068.6 pitches. Pitchers who did not require revision, in contrast, pitched 19.6% fewer pitches after reconstruction than before reconstruction (P = .08)., Conclusions: This study's findings suggest that MLB pitchers who require revision UCL reconstruction after returning to play following primary UCL reconstruction pitch at or above their pre-primary UCL reconstruction workload whereas control pitchers who do not require revision pitch significantly less, below their pre-primary UCL reconstruction workload., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)
- Published
- 2017
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39. Major League pitching workload after primary ulnar collateral ligament reconstruction and risk for revision surgery.
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Keller RA, Mehran N, Marshall NE, Okoroha KR, Khalil L, Tibone JE, and Moutzouros V
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- Adult, Case-Control Studies, Elbow Joint surgery, Humans, Male, Physical Endurance, Reoperation, Retrospective Studies, Risk Factors, Ulnar Collateral Ligament Reconstruction, Young Adult, Athletic Injuries prevention & control, Baseball injuries, Collateral Ligament, Ulnar surgery, Elbow Injuries
- Abstract
Background: Literature has attempted to correlate pitching workload with risk of ulnar collateral ligament (UCL) injury; however, limited data are available in evaluating workload and its relationship with the need for revision reconstruction in Major League Baseball (MLB) pitchers., Methods: We identified 29 MLB pitchers who underwent primary UCL reconstruction surgery and subsequently required revision reconstruction and compared them with 121 MLB pitchers who underwent primary reconstruction but did not later require revision surgery. Games pitched, pitch counts, and innings pitched were evaluated and compared for the seasons after returning from primary reconstruction and for the last season pitched before undergoing revision surgery., Results: The difference in workload between pitchers who did and did not require revision reconstruction was not statistically significant in games pitched, innings pitched, and MLB-only pitch counts. The one significant difference in workload was in total pitch counts (combined MLB and minor league), with the pitchers who required revision surgery pitching less than those who did not (primary: 1413.6 pitches vs. revision: 959.0 pitches, P = .04). In addition, pitchers who required revision surgery underwent primary reconstruction at an early age (22.9 years vs. 27.3 years, P < .001) and had less MLB experience (1.5 years vs. 5.0 years, P < .001)., Conclusions: There is no specific number of pitches, innings, or games that place a pitcher at an increase risk for injury after primary UCL reconstruction. However, correlations of risk may be younger age and less MLB experience at the time of the primary reconstruction., (Copyright © 2017. Published by Elsevier Inc.)
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- 2017
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40. Pain Assessment After Anterior Cruciate Ligament Reconstruction: Bone-Patellar Tendon-Bone Versus Hamstring Tendon Autograft.
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Okoroha KR, Keller RA, Jung EK, Khalil L, Marshall N, Kolowich PA, and Moutzouros V
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Background: Anterior cruciate ligament (ACL) reconstruction is a common outpatient procedure that is accompanied by significant postoperative pain., Purpose: To determine differences in acute pain levels between patients undergoing ACL reconstruction with bone-patellar tendon-bone (BTB) versus hamstring tendon (HS) autograft., Study Design: Cohort study; Level of evidence, 2., Methods: A total of 70 patients who underwent primary ACL reconstruction using either BTB or HS autografts consented to participate. The primary outcome of the study was postoperative pain levels (visual analog scale), which were collected immediately after surgery and for 3 days postoperatively. Secondary outcome measures included opioid consumption (intravenous morphine equivalents), hours slept, patient satisfaction, reported breakthrough pain, and calls to the physician., Results: Patients treated with BTB had increased pain when compared with those treated with HS in the acute postoperative period (mean ± SD: day 0, 6.0 ± 1.7 vs 5.2 ± 2.0 [ P = .066]; day 1, 5.9 ± 1.7 vs 4.9 ±1.7 [ P = .024]; day 2, 5.2 ± 1.9 vs 4.1 ± 2.0 [ P = .032]; day 3, 4.8 ± 2.1 vs 3.9 ± 2.3 [ P = .151]). There were also significant increases in reported breakthrough pain (day 0, 76% vs 43% [ P = .009]; day 1, 64% vs 35% [ P = .003]) and calls to the physician due to pain (day 1, 19% vs 0% [ P = .041]) in the BTB group. There were no significant differences in narcotic requirements or sleep disturbances. Overall, the BTB group reported significantly less satisfaction with pain management on days 0 and 1 ( P = .024 and .027, respectively)., Conclusion: A significant increase in acute postoperative pain was found when performing ACL reconstruction with BTB compared with HS. Patients treated with BTB were more likely to have breakthrough pain, decreased satisfaction with their pain management, and to contact their physician due to pain. These findings suggest a difference in early postoperative pain between the 2 most common graft options for ACL reconstruction. Patients should be informed of the differences in acute postoperative pain when deciding on graft choice with their physician., Competing Interests: The authors declared that they have no conflicts of interest in the authorship and publication of this contribution.
- Published
- 2016
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41. Radiostereometric Evaluation of Tendon Elongation After Distal Biceps Repair.
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Marshall NE, Keller RA, Okoroha K, Guest JM, Yu C, Muh S, and Moutzouros V
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Background: Operative repair of distal biceps tendon ruptures has shown successful outcomes. However, little is known about the amount of tendon or repair site lengthening after repair., Purpose/hypothesis: The purpose of this study was to evaluate distal biceps tendon repair via intratendinous radiostereometric analysis to analyze tendon lengthening at different time intervals of healing. The hypothesis was that there is significant lengthening after repair., Study Design: Case series; Level of evidence, 4., Methods: Eleven patients with distal biceps ruptures requiring operative repair were recruited. During repair, two 2-mm tantalum beads with laser-etched holes were sutured to the distal biceps tendon. Beads were evaluated via computed tomography scans immediately postoperatively and at 16 weeks. Radiographs were obtained at time 0 and then at 4, 8, and 16 weeks postoperatively. Measurements were made using the button-to-bead and bead-to-bead distances to assess repair site elongation as well as tendon elongation over time. After final follow-up, patients filled out the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire and underwent ultrasound to confirm the integrity of the tendon., Results: Ten patients had complete ruptures, with 1 having a partial rupture that underwent completion of the tear and subsequent repair. All patients showed statistically significant lengthening after surgery. The mean amount of tendon lengthening after surgery was 22.8 mm (range, 11.2-30.9 mm; P < .05), and the repair site lengthened a mean 17.0 mm (range, 9.6-30.6 mm; P < .05) from surgery to final follow-up. The greatest change in lengthening was noted between time 0 and week 4 (mean, 11.3 mm; P < .05), with the least amount of lengthening between weeks 8 and 16 (mean, 2.6 mm; P < .05). The mean DASH score was 11.2. Final ultrasound evaluations found all tendons to be in continuity., Conclusion: All patients undergoing distal biceps tendon repair have significant elongation after surgery, with the greatest amount of lengthening seen in the early postoperative period., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: This project was supported by a general medical education (GME) grant at Henry Ford Hospital to cover the cost of supplies and radiographic studies. Funding was provided by the Henry Ford Hospital Medical Education Department directly.
- Published
- 2016
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42. Liposomal bupivacaine versus interscalene nerve block for pain control after shoulder arthroplasty: a prospective randomized trial.
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Okoroha KR, Lynch JR, Keller RA, Korona J, Amato C, Rill B, Kolowich PA, and Muh SJ
- Subjects
- Aged, Aged, 80 and over, Amides administration & dosage, Brachial Plexus, Female, Humans, Male, Middle Aged, Prospective Studies, Ropivacaine, Shoulder Joint innervation, Shoulder Joint surgery, Visual Analog Scale, Anesthetics, Local administration & dosage, Arthroplasty, Replacement, Shoulder, Bupivacaine administration & dosage, Nerve Block methods, Pain, Postoperative prevention & control
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Hypothesis: Our hypothesis was that in patients undergoing shoulder arthroplasty, a prospective randomized trial would find no significant differences in average daily pain scores of those treated with interscalene nerve block (INB) vs. local liposomal bupivacaine (LB)., Methods: Sixty patients undergoing primary shoulder arthroplasty were assessed for eligibility. Study arms included either intraoperative local infiltration of LB (20 mL bupivacaine/20 mL saline) or preoperative INB, with a primary outcome of postoperative average daily visual analog scale scores for 4 days. Secondary outcomes assessed included opioid consumption, length of stay, and complications. Randomization was by a computerized algorithm. Only the observer was blinded to the intervention., Results: Three patients were excluded, all before randomization. A total of 57 patients were analyzed. Outcomes showed a significant increase in pain in the LB group between 0 and 8 hours postoperatively (mean [standard deviation] 5.3 [2.2] vs. 2.5 [3.0]; P = .001). A significant increase in intravenous morphine equivalents was found in the INB group at 13 to 16 hours (mean [standard deviation] 1.2 [0.9] vs. 0.6 [0.7]; P = .01). No significant differences were found in any variable after postoperative day 0 between the 2 groups., Conclusion: An increase in early postoperative pain on the day of surgery was found with LB, whereas the INB group required more narcotics at the end of the day. After the day of surgery, there were no significant differences found in any variables. These findings suggest that LB provides similar overall pain relief as INB, with no increase in complications or length of stay and a decrease in narcotic requirements on the day of surgery., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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43. Liposomal Bupivacaine Versus Femoral Nerve Block for Pain Control After Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Trial.
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Okoroha KR, Keller RA, Marshall NE, Jung EK, Mehran N, Owashi E, and Moutzouros V
- Subjects
- Adolescent, Adult, Female, Femoral Nerve, Humans, Male, Middle Aged, Prospective Studies, Visual Analog Scale, Young Adult, Anesthetics, Local therapeutic use, Anterior Cruciate Ligament Reconstruction, Bupivacaine therapeutic use, Nerve Block, Pain, Postoperative prevention & control
- Abstract
Purpose: To compare femoral nerve block (FNB) versus local liposomal bupivacaine (LB) for pain control in patients undergoing anterior cruciate ligament (ACL) reconstruction., Methods: Eighty-five patients undergoing primary ACL reconstruction were assessed for participation. We performed a prospective randomized trial in accordance with the CONSORT (Consolidated Standards of Reporting Trials) 2010 statement. The study arms included either intraoperative local infiltration of LB (20 mL of bupivacaine/10 mL of saline solution) or preoperative FNB with a primary outcome of postoperative pain levels (visual analog scale) for 4 days. Secondary outcomes assessed included opioid consumption (intravenous morphine equivalents), hours slept, patient satisfaction, and calls to the physician. Randomization was by a computerized algorithm. The observer was blinded and the patient was not blinded to the intervention., Results: One patient declined participation; 2 patients were excluded after randomization. A total of 82 patients were analyzed. Outcomes showed a significant increase in pain in the LB group between 5 and 8 hours postoperatively (mean ± standard deviation, 6.3 ± 2.0 versus 4.8 ± 2.6; P = .01). There were no significant differences between the groups in mean daily pain levels, morphine equivalents, or patient satisfaction when we controlled for graft type, age, body mass index, and sex. Patients receiving an FNB had a nonsignificant increase in number of sleep disturbances on the day of surgery (mean ± standard deviation, 4.4 ± 3.7 v 3.1 ± 2.1; P = .09) and were more likely to call their doctor the following day because of pain (29% v 8%, P = .04). Six patients in the FNB group had either prolonged quadriceps inhibition or sensory disturbance. One patient in the LB group required reoperation for a flexion contracture., Conclusions: An increase in acute postoperative pain was found with LB compared with FNB for post-ACL reconstruction pain control. After the acute postoperative period, there were no significant differences in opioid consumption or pain control. The occurrence of nerve irritation postoperatively was found to be higher in the FNB group., Level of Evidence: Level I, prospective randomized trial., (Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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44. Patient Perceptions of Reimbursement for Arthroscopic Meniscectomy and Anterior Cruciate Ligament Reconstruction.
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Okoroha KR, Keller RA, Marshall NE, Lynch JR, Guest JM, Lock T, and Rill B
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- Adult, Aged, Aged, 80 and over, Anterior Cruciate Ligament Reconstruction psychology, Female, Humans, Male, Medicare economics, Middle Aged, Suburban Health Services, Surveys and Questionnaires, United States, Urban Health Services, Anterior Cruciate Ligament Reconstruction economics, Arthroscopy economics, Attitude, Fees and Charges, Meniscus surgery, Orthopedics economics
- Abstract
Historically, patient perceptions of surgeon reimbursement have been exaggerated compared with actual reimbursement. There is limited information about patient perceptions of physician reimbursement for arthroscopic meniscectomy and anterior cruciate ligament (ACL) reconstruction. This study evaluated patient perceptions of physician reimbursement for these procedures and compared perceptions of health care reform between urban and suburban clinics. Surveys were given to 231 consecutive patients, and patients were asked how much they believed a surgeon should be reimbursed for arthroscopic meniscectomy and ACL reconstruction as well as their perception of actual Medicare reimbursement to physicians. Patients were then informed of the actual reimbursement rates and asked additional questions about health care reform. Survey responses were compared in an urban setting vs a suburban setting. On average, patients reported that surgeons should receive $8096 for meniscectomy and $11,794 for ACL reconstruction. Patients estimated that Medicare paid physicians $5442 for meniscectomy and $6667 for ACL reconstruction. In addition, 65% of patients believed that reimbursement for meniscectomy was too low, and 57% of patients believed that reimbursement for ACL reconstruction was too low. Fewer than 2% of patients believed that surgeon salaries should be cut, and 75% believed that orthopedic surgeons should be paid more for subspecialty training. No differences were found in patients' perceptions of reimbursement or health care reform between urban and suburban settings. Patients perceived that the values of meniscectomy and ACL reconstruction were substantially higher than current Medicare reimbursement values and that surgeon salaries should not be cut. [Orthopedics. 2016; 39(5):e904-e910.]., (Copyright 2016, SLACK Incorporated.)
- Published
- 2016
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45. Athletic Performance at the National Basketball Association Combine After Anterior Cruciate Ligament Reconstruction.
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Mehran N, Williams PN, Keller RA, Khalil LS, Lombardo SJ, and Kharrazi FD
- Abstract
Background: Anterior cruciate ligament (ACL) injuries are significant injuries in elite-level basketball players. In-game statistical performance after ACL reconstruction has been demonstrated; however, few studies have reviewed functional performance in National Basketball Association (NBA)-caliber athletes after ACL reconstruction., Purpose: To compare NBA Combine performance of athletes after ACL reconstruction with an age-, size-, and position-matched control group of players with no previous reported knee injury requiring surgery. We hypothesized that there is no difference between the 2 groups in functional performance., Study Design: Cross-sectional study; Level of evidence, 3., Methods: A total of 1092 NBA-caliber players who participated in the NBA Combine between 2000 and 2015 were reviewed. Twenty-one athletes were identified as having primary ACL reconstruction prior to participation in the combine. This study group was compared with an age-, size-, and position-matched control group in objective functional performance testing, including the shuttle run test, lane agility test, three-quarter court sprint, vertical jump (no step), and maximum vertical jump (running start)., Results: With regard to quickness and agility, both ACL-reconstructed athletes and controls scored an average of 11.5 seconds in the lane agility test and 3.1 seconds in the shuttle run test (P = .745 and .346, respectively). Speed and acceleration was measured by the three-quarter court sprint, in which both the study group and the control group averaged 3.3 seconds (P = .516). In the maximum vertical jump, which demonstrates an athlete's jumping ability with a running start, the ACL reconstruction group had an average height of 33.6 inches while the controls averaged 33.9 inches (P = .548). In the standing vertical jump, the ACL reconstruction group averaged 28.2 inches while the control group averaged 29.2 inches (P = .067)., Conclusion: In athletes who are able to return to sport and compete at a high level such as the NBA Combine, there is no significant difference in any combine performance test between players who have had primary ACL reconstruction compared with an age-, size-, and position-matched control group., Clinical Relevance: Athletes with previous ACL reconstruction who are able to return to high-level professional basketball have equivalent performance measures with regard to speed, quickness, and jumping ability as those athletes who have not undergone knee surgery.
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- 2016
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46. Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.
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Keller RA, Marshall NE, Guest JM, Okoroha KR, Jung EK, and Moutzouros V
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- Adult, Athletic Injuries surgery, Baseball statistics & numerical data, Case-Control Studies, Collateral Ligaments surgery, Elbow Joint surgery, Humans, Male, Risk Factors, Young Adult, Athletic Injuries epidemiology, Baseball injuries, Collateral Ligaments injuries, Elbow Injuries
- Abstract
Background: The number of Major League Baseball (MLB) pitchers requiring ulnar collateral ligament (UCL) reconstructions is increasing. Recent literature has attempted to correlate specific stresses placed on the throwing arm to risk for UCL injury, with limited results., Methods: Eighty-three MLB pitchers who underwent primary UCL reconstruction were evaluated. Pitching velocity and percent of pitch type thrown (fastball, curve ball, slider, and change-up) were evaluated 2 years before and after surgery. Data were compared with control pitchers matched for age, position, size, innings pitched, and experience., Results: The evaluation of pitch velocity compared with matched controls found no differences in pre-UCL reconstruction pitch velocities for fastballs (91.5 vs. 91.2 miles per hour [mph], P = .69), curveballs (78.2 vs. 77.9 mph, P = .92), sliders (83.3 vs. 83.5 mph, P = .88), or change-ups (83.9 vs. 83.8 mph, P = .96). When the percentage of pitches thrown was evaluated, UCL reconstructed pitchers pitch significantly more fastballs than controls (46.7% vs. 39.4%, P = .035). This correlated to a 2% increase in risk for UCL injury for every 1% increase in fastballs thrown. Pitching more than 48% fastballs was a significant predictor of UCL injury, because pitchers over this threshold required reconstruction (P = .006)., Conclusion: MLB pitchers requiring UCL reconstruction do not pitch at higher velocities than matched controls, and pitch velocity does not appear to be a risk factor for UCL reconstruction. However, MLB pitchers who pitch a high percentage of fastballs may be at increased risk for UCL injury because pitching a higher percent of fastballs appears to be a risk factor for UCL reconstruction., (Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)
- Published
- 2016
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47. Skin diseases associated with Agent Orange and other organochlorine exposures.
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Patterson AT, Kaffenberger BH, Keller RA, and Elston DM
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- Agent Orange, Female, Follow-Up Studies, Humans, Incidence, Male, Risk Assessment, Skin Diseases epidemiology, Skin Diseases physiopathology, United States, Vietnam, 2,4,5-Trichlorophenoxyacetic Acid adverse effects, 2,4-Dichlorophenoxyacetic Acid adverse effects, Environmental Exposure adverse effects, Hydrocarbons, Chlorinated adverse effects, Military Personnel, Polychlorinated Dibenzodioxins adverse effects, Skin Diseases chemically induced
- Abstract
Organochlorine exposure is an important cause of cutaneous and systemic toxicity. Exposure has been associated with industrial accidents, intentional poisoning, and the use of defoliants, such as Agent Orange in the Vietnam War. Although long-term health effects are systematically reviewed by the Institute of Medicine, skin diseases are not comprehensively assessed. This represents an important practice gap as patients can present with cutaneous findings. This article provides a systematic review of the cutaneous manifestations of known mass organochlorine exposures in military and industrial settings with the goal of providing clinically useful recommendations for dermatologists seeing patients inquiring about organochlorine effects. Patients with a new diagnosis of chloracne, porphyria cutanea tarda, cutaneous lymphomas (non-Hodgkin lymphoma), and soft-tissue sarcomas including dermatofibrosarcoma protuberans and leiomyosarcomas should be screened for a history of Vietnam service or industrial exposure. Inconclusive evidence exists for an increased risk of other skin diseases in Vietnam veterans exposed to Agent Orange including benign fatty tumors, melanomas, nonmelanoma skin cancers, milia, eczema, dyschromias, disturbance of skin sensation, and rashes not otherwise specified. Affected veterans should be informed of the uncertain data in those cases. Referral to Department of Veterans Affairs for disability assessment is indicated for conditions with established associations., (Copyright © 2015 American Academy of Dermatology, Inc. All rights reserved.)
- Published
- 2016
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48. Athletic Performance at the NFL Scouting Combine After Anterior Cruciate Ligament Reconstruction.
- Author
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Keller RA, Mehran N, Austin W, Marshall NE, Bastin K, and Moutzouros V
- Subjects
- Adult, Case-Control Studies, Humans, Male, Retrospective Studies, Young Adult, Anterior Cruciate Ligament Injuries, Anterior Cruciate Ligament Reconstruction, Athletic Performance, Football injuries, Knee Injuries surgery
- Abstract
Background: Anterior cruciate ligament (ACL) injuries are common and potentially career ending in the National Football League (NFL). Although statistical performance has been demonstrated after ACL reconstruction, functional performance is not well defined., Purpose/hypothesis: The purpose of this study was to determine the functional performance of NFL combine participants after ACL reconstruction compared with an age-, size-, and position-matched control group. The hypothesis was that there would be no difference between players after ACL reconstruction as compared with controls in functional athletic performance., Study Design: Cohort study; Level of evidence, 3., Methods: A total of 98 NFL-caliber athletes who had undergone primary ACL reconstruction and participated in the NFL scouting combine between 2010 and 2014 were reviewed and compared with an age-, size-, and position-matched control group. Data recorded for each player included a 40-yard dash, vertical leap, broad jump, shuttle drill, and 3-cone drill., Results: With regard to speed and acceleration, the mean 40-yard dash time for ACL-reconstructed players was 4.74 seconds (range, 4.33-5.55 seconds) compared with controls at 4.74 seconds (range, 4.34-5.38 seconds; P = .96). Jumping performance was also similar, with a mean vertical leap for ACL-reconstructed players of 33.35 inches (range, 23-43 inches) and broad jump of 113.9 inches (range, 96-136 inches) compared with respective values for the controls of 33.22 inches (range, 23.5-43.5 inches; P = .84) and 113.9 inches (range, 92-134 inches; P = .99). Agility and quickness testing measures also did not show a statistically significantly difference, with ACL-reconstructed players performing the shuttle drill in 4.37 seconds (range, 4.02-4.84 seconds) and the 3-cone drill in 7.16 seconds (range, 6.45-8.14 seconds), respectively, compared with respective times for the controls of 4.37 seconds (range, 3.96-5.00 seconds; P = .91) and 7.18 seconds (range, 6.64-8.24 seconds; P = .75)., Conclusion: This study suggests that after ACL reconstruction, high-caliber athletes can achieve equivalent levels of performance with no statistically significant differences compared with matched controls. This information is unique when advising high-level athletes on athletic performance after ACL reconstruction, suggesting that those who fully recover and return to play appear to have no decrement in athletic performance., (© 2015 The Author(s).)
- Published
- 2015
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49. Ulnar Collateral Ligament and Elbow Adaptations in High School Baseball Pitchers.
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Marshall NE, Keller RA, Van Holsbeeck M, and Moutzouros V
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- Adolescent, Arm physiology, Calcinosis diagnostic imaging, Cross-Sectional Studies, Humans, Joint Instability diagnostic imaging, Male, Range of Motion, Articular, Rotation, Shoulder physiology, Ultrasonography, Adaptation, Physiological, Baseball physiology, Collateral Ligaments diagnostic imaging, Collateral Ligaments physiology, Elbow diagnostic imaging, Elbow physiology
- Abstract
Background: Baseball pitchers have adaptive changes in the soft tissues of the throwing elbow., Hypothesis: High school baseball pitchers would show adaptive changes in the ulnar collateral ligament (UCL), such as calcifications and hypoechoic foci, thickening, and increased ulnohumeral joint laxity, on dynamic ultrasound (DUS)., Study Design: Cross-sectional study., Level of Evidence: Level 3., Methods: Twenty-two asymptomatic high school pitchers, designated as their primary position by their coach, underwent DUS and physical examination of the throwing and nonthrowing elbows prior to the start of the season. UCL substance consistency and thickness, ulnohumeral joint space widening, and soft tissue elbow structures were evaluated., Results: The mean age of the cohort was 16.9 years. Calcifications of the UCL were similar, being present in 7 of 22 (32%) throwing elbows versus 8 of 22 (36%) nonthrowing elbows (P = 0.11). UCL hypoechoic foci also were similar between elbows: 2 of 22 (9%) throwing elbows versus 0 of 22 nonthrowing elbows (P = 0.11). UCL thickness was also found to be similar in both elbows (throwing arm, 6.54 mm vs nonthrowing, 6.71 mm; P = 0.48). Ulnohumeral joint laxity unloaded (throwing arm, 3.13 mm vs nonthrowing, 3.17 mm; P = 0.835) and loaded (throwing arm, 3.87 mm vs nonthrowing arm, 4.11 mm; P = 0.30) was similar between elbows. Throwing elbows showed posteromedial olecranon spurring in 36%, effusions in 27%, and synovitis in 9%., Conclusion: High school pitchers show limited adaptive changes in the elbow, including UCL calcifications, hypoechoic foci, posteromedial olecranon spurring, and effusions. However, these changes are similar to those seen in the nonthrowing elbow, and these younger athletes lack findings seen in professional and collegiate pitchers such as UCL thickening and increased ulnohumeral joint space laxity., Clinical Relevance: Preseason ultrasound examination of the high school pitching elbow lacks the adaptive changes to the elbow as seen in professional pitchers. These changes likely occur later in a pitcher's career., (© 2015 The Author(s).)
- Published
- 2015
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50. Pre- and Postseason Dynamic Ultrasound Evaluation of the Pitching Elbow.
- Author
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Keller RA, Marshall NE, Bey MJ, Ahmed H, Scher CE, van Holsbeeck M, and Moutzouros V
- Subjects
- Adolescent, Anatomy, Cross-Sectional, Collateral Ligaments diagnostic imaging, Humans, Male, Prospective Studies, Random Allocation, Ulnar Nerve diagnostic imaging, Ultrasonography, Baseball physiology, Elbow diagnostic imaging, Elbow Joint diagnostic imaging
- Abstract
Purpose: To use ultrasound imaging to document changes over time (i.e., preseason v postseason) in the pitching elbow of high school baseball pitchers., Methods: Twenty-two high school pitchers were prospectively followed. Pitchers were evaluated after a 2-month period of relative arm rest via preseason physical exams, dynamic ultrasound imaging of their throwing elbow, and the Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) assessment. Players were reevaluated within 1 week of their last game. Dynamic ultrasound images were then randomized, blinded to testing time point, and evaluated by 2 fellowship-trained musculoskeletal radiologists., Results: Average pitcher age was 16.9 years. Average pitches thrown was 456.5, maximum velocity 77.7 mph, games pitched 7.3, and days off between starts 6.6. From preseason to postseason, there were significant increases in ulnar collateral ligament (UCL) thickness (P = .02), ulnar nerve cross-sectional area (P = .001), UCL substance heterogeneity (P = .001), and QuickDASH scores (P = .03). In addition, there was a nonsignificant increase in loaded ulnohumeral joint space (P = .10). No pitchers had loose bodies on preseason exam, while 3 demonstrated loose bodies postseason. The increase in UCL thickness was significantly associated with the number of bullpen sessions per week (P = .01). The increase in ulnar nerve cross-sectional area was significantly associated with the number of pitches (P = .04), innings pitched (P = .01), and games pitched (P = .04)., Conclusions: The stresses placed on the elbow during only one season of pitching create adaptive changes to multiple structures about the elbow including UCL heterogeneity and thickening, increased ulnohumeral joint space laxity, and enlarged ulnar nerve cross-sectional area., Level of Evidence: Level II prospective observational study., (Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)
- Published
- 2015
- Full Text
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