Search

Category: Trauma; Ankle Arthritis Introduction/Purpose: The purpose of this study was to identify the risk factors for posttraumatic osteoarthritis (OA) after surgery for ankle fractures in patients aged 50 years or less. Methods: We performed a retrospective review of consecutive patients who underwent surgery for ankle fractures and were followed up for a minimum period of 5 years. The patients were assigned to 2 group according to the presence of advanced OA at the last follow-up. Binary logistic regression was used to model the correlation between various risk factors and OA. Functional outcomes were assessed using the Foot and Ankle Outcome Score. Results: The data of 332 patients who met the study inclusion criteria were included in the analysis. The overall rate of posttraumatic arthritic change was 27.7% (non-arthritis group: 240 patients, arthritis group: 92 patients). The arthritic change was significantly affected by BMI (p = 0.011; adjusted odds ratio [OR] >= 30, 6.56), fracture-dislocation injury (p = 0.025; adjusted OR, 4.06), posterior malleolus (PM) fracture (p = 0.031, adjusted OR > 25% of the articular surface, 5.72), and postoperative articular incongruence (p = 0.034; adjusted OR, 7.21). The mean scores of the arthritis group were lower than those in the non-arthritis group (p

Background: The relationship between preoperative subchondral bone marrow edema (BME) in the osteoarthritic knee and pain has been established. However, little is known about the influence of preoperative BME on outcomes after medial opening-wedge high tibial osteotomy (MOHTO). The purpose of this study was to clarify the association between preoperative BME severity and clinical outcomes after MOHTO at intermediate follow-up.Methods: We reviewed the cases of 105 consecutive patients who underwent MOHTO for osteoarthritis of the knee with preoperative subchondral BME in the medial aspect of the tibia between January 2005 and December 2015. BME was evaluated using magnetic resonance imaging (MRI). The sizes of the BME lesions were determined on the basis of the maximum diameter and were classified as small (<1 cm), medium (<2 cm), large (<4 cm), or very large (diffuse; >4 cm). Associations between preoperative BME severity and postoperative outcomes at a mean follow-up of 6.2 years (range, 2.0 to 14.3 years) were evaluated according to a Spearman correlation matrix with each reviewer's grades. Functional outcomes were assessed using the Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS), and Short Form-12 (SF-12) questionnaire. Survival rate and complications were also evaluated.Results: The degree of preoperative BME was not significantly correlated with postoperative outcomes (p > 0.05). There were significant improvements between the preoperative and latest follow-up assessments in all functional outcome categories (p < 0.001). Patients demonstrated marked improvements with respect to pain, function, and quality of life. The overall survival rate was 95.2%, with a mean follow-up of 6.2 years. Six major complications were identified in 5.7% of the patients, and these resulted in 5 patients (4.8%) who had conversion to total knee arthroplasty.Conclusions: We did not find any correlation between preoperative subchondral BME severity and postoperative outcomes. MOHTO showed good functional outcomes, a low major complication rate, and an excellent survival rate with a mean follow-up of 6.2 years, regardless of the degree of preoperative BME.Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

We report studies of the relationships between the total bolometric luminosity (L bol or L TIR) and the molecular line luminosities of J  = 1 − 0 transitions of H13CN, H13CO+, HCN, and HCO+ with data obtained from ACA observations in the 'ATOMS' survey of 146 active Galactic star-forming regions. The correlations between L bol and molecular line luminosities |$L^{\prime }_{\rm mol}$| of the four transitions all appear to be approximately linear. Line emission of isotopologues shows as large scatters in L bol– |$L^{\prime }_{\rm mol}$| relations as their main line emission. The log(L bol/ |$L^{\prime }_{\rm mol}$|⁠) for different molecular line tracers have similar distributions. The L bol-to- |$L^{\prime }_{\rm mol}$| ratios do not change with galactocentric distances (R GC) and clump masses (M clump). The molecular line luminosity ratios (HCN-to-HCO+, H13CN-to-H13CO+, HCN-to-H13CN, and HCO+-to-H13CO+) all appear constant against L bol, dust temperature (T d), M clump, and R GC. Our studies suggest that both the main lines and isotopologue lines are good tracers of the total masses of dense gas in Galactic molecular clumps. The large optical depths of main lines do not affect the interpretation of the slopes in star formation relations. We find that the mean star formation efficiency (SFE) of massive Galactic clumps in the 'ATOMS' survey is reasonably consistent with other measures of the SFE for dense gas, even those using very different tracers or examining very different spatial scales. [ABSTRACT FROM AUTHOR]

The ATOMS, standing for ALMA Three-millimeter Observations of Massive Star-forming regions, survey has observed 146 active star-forming regions with ALMA band 3, aiming to systematically investigate the spatial distribution of various dense gas tracers in a large sample of Galactic massive clumps, to study the roles of stellar feedback in star formation, and to characterize filamentary structures inside massive clumps. In this work, the observations, data analysis, and example science of the ATOMS survey are presented, using a case study for the G9.62+0.19 complex. Toward this source, some transitions, commonly assumed to trace dense gas, including CS J  = 2−1, HCO+ J  = 1−0, and HCN J  = 1−0, are found to show extended gas emission in low-density regions within the clump; less than 25 per cent of their emission is from dense cores. SO, CH3OH, H13CN, and HC3N show similar morphologies in their spatial distributions and reveal well the dense cores. Widespread narrow SiO emission is present (over ∼1 pc), which may be caused by slow shocks from large–scale colliding flows or H  ii regions. Stellar feedback from an expanding H  ii region has greatly reshaped the natal clump, significantly changed the spatial distribution of gas, and may also account for the sequential high-mass star formation in the G9.62+0.19 complex. The ATOMS survey data can be jointly analysed with other survey data, e.g. MALT90, Orion B, EMPIRE, ALMA_IMF, and ALMAGAL, to deepen our understandings of 'dense gas' star formation scaling relations and massive protocluster formation. [ABSTRACT FROM AUTHOR]

In the episodic accretion scenario, a large fraction of the protostellar mass accretes during repeated and large bursts of accretion. Since outbursts on protostars are typically identified at specific wavelengths, interpreting these outbursts requires converting this change in flux to a change in total luminosity. The Class I young stellar object EC 53 in the Serpens Main cloud has undergone repeated increases in brightness at 850 μm that are likely caused by bursts of accretion. In this study, we perform two- and three-dimensional continuum radiative transfer modeling to quantify the internal luminosity rise in EC 53 that corresponds to the factor of ∼1.5 enhancement in flux at 850 μm. We model the spectral energy distribution and radial intensity profile in both the quiescent and outburst phases. The internal luminosity in the outburst phase is ∼3.3 times brighter than the luminosity in the quiescent phase. The radial intensity profile analysis demonstrates that the detected submillimeter flux variation of EC 53 comes from the heated envelope by the accretion burst. We also find that the role of external heating of the EC 53 envelope by the interstellar radiation field is insignificant. [ABSTRACT FROM AUTHOR]

Context. Current theories and models attempt to explain star formation globally, from core scales to giant molecular cloud scales. A multi-scale observational characterisation of an entire molecular complex is necessary to constrain them. We investigate star formation in G202.3+2.5, a ∼10 × 3 pc sub-region of the Monoceros OB1 cloud with a complex morphology that harbours interconnected filamentary structures. Aims. We aim to connect the evolution of cores and filaments in G202.3+2.5 with the global evolution of the cloud and to identify the engines of the cloud dynamics. Methods. In this first paper, the star formation activity is evaluated by surveying the distributions of dense cores and protostars and their evolutionary state, as characterised using both infrared observations from the Herschel and WISE telescopes and molecular line observations with the IRAM 30 m telescope. Results. We find ongoing star formation in the whole cloud, with a local peak in star formation activity around the centre of G202.3+2.5, where a chain of massive cores (10 − 50 M⊙) forms a massive ridge (≳150 M⊙). All evolutionary stages from starless cores to Class II protostars are found in G202.3+2.5, including a possibly starless and massive (52 M⊙) core, which presents a high column density (8 × 1022 cm−2). Conclusions. All the core-scale observables we examined point to an enhanced star formation activity that is centred on the junction between the three main branches of the ramified structure of G202.3+2.5. This suggests that the increased star formation activity results from the convergence of these branches. To further investigate the origin of this enhancement, it is now necessary to extend the analysis to larger scales in order to examine the relationship between cores, filaments, and their environment. We address these points through the analysis of the dynamics of G202.3+2.5 in a joint paper. [ABSTRACT FROM AUTHOR]

Context. We started a multi-scale analysis of star formation in G202.3+2.5, an intertwined filamentary sub-region of the Monoceros OB1 molecular complex, in order to provide observational constraints on current theories and models that attempt to explain star formation globally. In the first paper (Paper I), we examined the distributions of dense cores and protostars and found enhanced star formation activity in the junction region of the filaments. Aims. In this second paper, we aim to unveil the connections between the core and filament evolutions, and between the filament dynamics and the global evolution of the cloud. Methods. We characterise the gas dynamics and energy balance in different parts of G202.3+2.5 using infrared observations from the Herschel and WISE telescopes and molecular tracers observed with the IRAM 30-m and TRAO 14-m telescopes. The velocity field of the cloud is examined and velocity-coherent structures are identified, characterised, and put in perspective with the cloud environment. Results. Two main velocity components are revealed, well separated in radial velocities in the north and merged around the location of intense N2H+ emission in the centre of G202.3+2.5 where Paper I found the peak of star formation activity. We show that the relative position of the two components along the sightline, and the velocity gradient of the N2H+ emission imply that the components have been undergoing collision for ~105 yr, although it remains unclear whether the gas moves mainly along or across the filament axes. The dense gas where N2H+ is detected is interpreted as the compressed region between the two filaments, which corresponds to a high mass inflow rate of ~1 × 10−3M⊙ yr−1 and possibly leads to a significant increase in its star formation efficiency. We identify a protostellar source in the junction region that possibly powers two crossed intermittent outflows. We show that the H II region around the nearby cluster NCG 2264 is still expanding and its role in the collision is examined. However, we cannot rule out the idea that the collision arises mostly from the global collapse of the cloud. Conclusions. The (sub-)filament-scale observables examined in this paper reveal a collision between G202.3+2.5 sub-structures and its probable role in feeding the cores in the junction region. To shed more light on this link between core and filament evolutions, one must characterise the cloud morphology, its fragmentation, and magnetic field, all at high resolution. We consider the role of the environment in this paper, but a larger-scale study of this region is now necessary to investigate the scenario of a global cloud collapse. [ABSTRACT FROM AUTHOR]

Young stars exhibit variability due to changes in the gas accretion rate onto them, an effect that should be quite significant in the early stages of their formation. As protostars are embedded within their natal cloud, this variability may only be inferred through long wavelength observations. We perform radiative transfer simulations of young stellar objects (YSOs) formed in hydrodynamical simulations, varying the structure and luminosity properties in order to estimate the long-wavelength, sub-mm and mm, variations of their flux. We find that the flux increase due to an outburst event depends on the protostellar structure and is more prominent at sub-mm wavelengths than at mm wavelengths; e.g. a factor of 40 increase in the luminosity of the young protostar leads to a flux increase of a factor of 10 at 250  μ m but only a factor of 2.5 at 1.3 mm. We find that the interstellar radiation field dilutes the flux increase but that this effect may be avoided if resolution permits the monitoring of the inner regions of a YSO, where the heating is primarily due to protostellar radiation. We also confirm that the bolometric temperature and luminosity of outbursting protostars may result in an incorrect classification of their evolutionary stage. [ABSTRACT FROM AUTHOR]

Accretion onto protostars may occur in sharp bursts. Accretion bursts during the embedded phase of young protostars are probably most intense, but can only be inferred indirectly through long-wavelength observations. We perform radiative transfer calculations for young stellar objects (YSOs) formed in hydrodynamic simulations to predict the long wavelength, sub-mm and mm, flux responses to episodic accretion events, taking into account heating from the young protostar and from the interstellar radiation field. We find that the flux increase due to episodic accretion events is more prominent at sub-mm wavelengths than at mm wavelengths; e.g. a factor of ∼570 increase in the luminosity of the young protostar leads to a flux increase of a factor of 47 at 250  |$\mu$| m but only a factor of 10 at 1.3 mm. Heating from the interstellar radiation field may reduce further the flux increase observed at longer wavelengths. We find that during FU Ori-type outbursts the bolometric temperature and luminosity may incorrectly classify a source as a more evolved YSO due to a larger fraction of the radiation of the object being emitted at shorter wavelengths. [ABSTRACT FROM AUTHOR]

We present the first release of the data and compact-source catalogue for the JCMT Large Program SCUBA-2 Continuum Observations of Pre-protostellar Evolution (SCOPE). SCOPE consists of 850  |$\mu$| m continuum observations of 1235 Planck Galactic Cold Clumps (PGCCs) made with the Submillimetre Common-User Bolometer Array 2 on the James Clerk Maxwell Telescope. These data are at an angular resolution of 14.4 arcsec, significantly improving upon the 353 GHz resolution of Planck at 5 arcmin, and allowing for a catalogue of 3528 compact sources in 558 PGCCs. We find that the detected PGCCs have significant sub-structure, with 61 per cent of detected PGCCs having three or more compact sources, with filamentary structure also prevalent within the sample. A detection rate of 45 per cent is found across the survey, which is 95 per cent complete to Planck column densities of |$N_{\rm {H_{2}}}$| > 5 × 1021 cm−2. By positionally associating the SCOPE compact sources with young stellar objects, the star formation efficiency, as measured by the ratio of luminosity to mass, in nearby clouds is found to be similar to that in the more distant Galactic Plane, with the column density distributions also indistinguishable from each other. [ABSTRACT FROM AUTHOR]

We present an analysis of HCO+ (J = 3 → 2) and H13CO+ (J = 3 → 2) observations of the massive (M ∼ 20 M☼) submillimeter/IR source IRAS 01202+6133 located on the periphery of the H II region KR 120 (Sh 2-187). The HCO+ line profile has a classic blue-asymmetric shape with the optically thin H13CO+ line peaking at the position expected if the HCO+ line arises from a combination of self-absorption and infall motion. We have modified existing analytic radiative transfer models to allow for the fitting of submillimeter/millimeter line profiles that have both self-absorption features and optically thin wings and applied these models to our HCO+ spectrum of IRAS 01202+6133. We conclude that it is a young Class I young stellar object with a substantial envelope undergoing slow infall and having some outflow motions. The young age of the H II region rules out a “collect and collapse” scenario. While we cannot eliminate the possibility that IRAS 01202+6133 formed spontaneously at its current location, considering its early evolutionary state and its proximity to the H II region, we think that the formation of IRAS 01202+6133 was triggered by the expansion of KR 120 (Sh 2-187). [ABSTRACT FROM AUTHOR]

Background: To report the long-term clinical and radiologic results of impaction bone grafting and standard cemented polished stem for femoral revision arthroplasty in patients with extensive bone deficiency., Methods: We retrospectively reviewed 47 hips that underwent femoral revision hip arthroplasty using an impaction-morselized allograft with a standard cemented polished stem. The average age at the time of revision hip arthroplasty was 55 years (range, 39-75 years). The modified Harris hip score (HHS) was used for clinical evaluation. The radiologic evaluation focused on stem subsidence, stem position, progressive radiolucent lines, bone remodeling, and the incorporation of allografts., Results: The modified HHS improved from an average of 55.04 (range, 25-79.5) preoperatively to 90.1 (range, 81-93.2) at the last follow-up. The mean follow-up duration was 13.5 years (10.9-17.8 years). The radiographic analysis revealed stable stems. Femoral stems showed an average subsidence of 3.2 mm (range, 2-8 mm) in the cement mantle. However, there was no mechanical failure or subsidence of the cement mantle in the femurs. The stem position was neutral or varus less than 5°. No progressive radiolucent line or osteolysis was observed. Evidence of cortical and trabecular remodeling was observed in all cases. There were four cases of intraoperative cracks and four cases of distal femur splitting., Conclusions: Initial stem stability using impaction bone grafting and a standard cemented polished stem in femoral revision arthroplasty resulted in good outcome. Delicate impaction grafting techniques and intraoperative crack and splitting fixation are the points that need attention for successful long-term results., Competing Interests: CONFLICT OF INTEREST: No potential conflict of interest relevant to this article was reported., (Copyright © 2023 by The Korean Orthopaedic Association.)

Aims: To determine the relationship between articular cartilage status and clinical outcomes after medial opening-wedge high tibial osteotomy (MOHTO) for medial compartmental knee osteoarthritis at intermediate follow-up., Methods: We reviewed 155 patients (155 knees) who underwent MOHTO from January 2008 to December 2016 followed by second-look arthroscopy with a mean 5.3-year follow-up (2.0 to 11.7). Arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system. Patients were divided into two groups based on the presence of normal or nearly normal quality cartilage in the medial femoral condyle: good (second-look arthroscopic) status (ICRS grade I or II; n = 70), and poor (second-look arthroscopic) status (ICRS grade III or IV; n = 85) groups at the time of second-look arthroscopy. Clinical outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-Item Short Form survey., Results: Significant improvements in all clinical outcome categories were found between the preoperative and second-look arthroscopic assessments in both groups (p < 0.001). At the latest follow-up, the mean IKDC and WOMAC scores in the good status group further improved compared with those at the time of second-look arthroscopic surgery (p < 0.001), which was not shown in the poor status group. The mean IKDC (good status, 72.8 (SD 12.5); poor status, 64.7 (SD 12.1); p = 0.002) and mean WOMAC scores (good status, 15.7 (SD 10.8); poor status, 21.8 (SD 13.6); p = 0.004) significantly differed between both groups at the latest follow-up. Moreover, significant correlations were observed between ICRS CRA grades and IKDC scores (negative correlation; p < 0.001) and WOMAC scores (positive correlation; p < 0.001) at the latest follow-up. Good cartilage status was found more frequently in knees with the desired range of 2° to 6° valgus correction than in those with corrections outside this range (p = 0.019)., Conclusion: Second-look arthroscopic cartilage status correlated with clinical outcomes after MOHTO at intermediate-term follow-up, despite the relatively small clinical differences between groups. Cite this article: Bone Joint J  2021;103-B(11):1686-1694.

Background: The relationship between preoperative subchondral bone marrow edema (BME) in the osteoarthritic knee and pain has been established. However, little is known about the influence of preoperative BME on outcomes after medial opening-wedge high tibial osteotomy (MOHTO). The purpose of this study was to clarify the association between preoperative BME severity and clinical outcomes after MOHTO at intermediate follow-up., Methods: We reviewed the cases of 105 consecutive patients who underwent MOHTO for osteoarthritis of the knee with preoperative subchondral BME in the medial aspect of the tibia between January 2005 and December 2015. BME was evaluated using magnetic resonance imaging (MRI). The sizes of the BME lesions were determined on the basis of the maximum diameter and were classified as small (<1 cm), medium (<2 cm), large (<4 cm), or very large (diffuse; >4 cm). Associations between preoperative BME severity and postoperative outcomes at a mean follow-up of 6.2 years (range, 2.0 to 14.3 years) were evaluated according to a Spearman correlation matrix with each reviewer's grades. Functional outcomes were assessed using the Hospital for Special Surgery (HSS) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Society Score (KSS), and Short Form-12 (SF-12) questionnaire. Survival rate and complications were also evaluated., Results: The degree of preoperative BME was not significantly correlated with postoperative outcomes (p > 0.05). There were significant improvements between the preoperative and latest follow-up assessments in all functional outcome categories (p < 0.001). Patients demonstrated marked improvements with respect to pain, function, and quality of life. The overall survival rate was 95.2%, with a mean follow-up of 6.2 years. Six major complications were identified in 5.7% of the patients, and these resulted in 5 patients (4.8%) who had conversion to total knee arthroplasty., Conclusions: We did not find any correlation between preoperative subchondral BME severity and postoperative outcomes. MOHTO showed good functional outcomes, a low major complication rate, and an excellent survival rate with a mean follow-up of 6.2 years, regardless of the degree of preoperative BME., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Diabetes can be efficiently prevented by life style modification and medical therapy. So, identification for high risk subjects for incident type 2 diabetes is important. The aim of this study is to identify the best β-cell function index to identify high risk subjects in non-diabetic Koreans., Methods: This is a retrospective longitudinal study. Total 140 non-diabetic subjects who underwent standard 2-hour 75 g oral glucose tolerance test from January 2007 to February 2007 at Kangbuk Samsung Hospital and followed up for more than 1 year were analyzed (mean follow-up, 54.9±16.4 months). The subjects were consist of subjects with normal glucose tolerance (n=44) and subjects with prediabetes (n=97) who were 20 years of age or older. Samples for insulin and C-peptide levels were obtained at 0 and 30 minutes at baseline., Results: Thirty subjects out of 140 subjects (21.4%) developed type 2 diabetes. When insulin-based index and C-peptide-based index are compared between progressor and non-progressor to diabetes, all C-peptide-based indices were statistically different between two groups, but only insulinogenic index and disposition index among insulin-based index were statistically different. C-peptide-based index had higher value of area under receiver operating characteristic curve (AROC) value than that of insulin-based index. "C-peptidogenic" index had highest AROC value among indices (AROC, 0.850; 95% confidence interval, 0.761 to 0.915). C-peptidogenic index had significantly higher AROC than insulinogenic index (0.850 vs. 0.731 respectively; P=0.014)., Conclusion: C-peptide-based index was more closely related to incident type 2 diabetes in non-diabetic subjects than insulin-based index.