| 1. |
- Wagner, J., et al.
(författare)
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First 230? : GHz VLBI fringes on 3C 279 using the APEX Telescope (Research Note)
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 581
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We report about a 230? GHz very long baseline interferometry (VLBI) fringe finder observation of blazar 3C 279 with the APEX telescope in Chile, the phased submillimeter array (SMA), and the SMT of the Arizona Radio Observatory (ARO). Methods. We installed VLBI equipment and measured the APEX station position to 1? cm accuracy (1σ). We then observed 3C 279 on 2012 May 7 in a 5? h 230? GHz VLBI track with baseline lengths of 2800? Mλ to 7200? Mλ and a finest fringe spacing of 28.6? μas. Results. Fringes were detected on all baselines with signal-to-noise ratios of 12 to 55 in 420? s. The correlated flux density on the longest baseline was ∼0.3? Jy beam-1, out of a total flux density of 19.8? Jy. Visibility data suggest an emission region ≤ 38? μas in size, and at least two components, possibly polarized. We find a lower limit of the brightness temperature of the inner jet region of about 1010? K. Lastly, we find an upper limit of 20% on the linear polarization fraction at a fringe spacing of ∼ 38? μas. Conclusions. With APEX the angular resolution of 230? GHz VLBI improves to 28.6? μas. This allows one to resolve the last-photon ring around the Galactic Center black hole event horizon, expected to be 40? μas in diameter, and probe radio jet launching at unprecedented resolution, down to a few gravitational radii in galaxies like M 87. To probe the structure in the inner parsecs of 3C 279 in detail, follow-up observations with APEX and five other mm-VLBI stations have been conducted (March 2013) and are being analyzed.
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| 2. |
- Al Dabbagh, Zewar, et al.
(författare)
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No signs of dose escalations of potent opioids prescribed after tibial shaft fractures : a study of Swedish National Registries
- 2014
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Ingår i: BMC Anesthesiology. - London : BioMed Central. - 1471-2253 .- 1471-2253. ; 14, s. 4-
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Tidskriftsartikel (refereegranskat)abstract
- Background: The pattern of opioid use after skeletal trauma is a neglected topic in pain medicine. The purpose of this study was to analyse the long-term prescriptions of potent opioids among patients with tibial shaft fractures.Methods: Data were extracted from the Swedish National Hospital Discharge Register, the National Pharmacy Register, and the Total Population Register, and analysed accordingly. The study period was 2005-2008.Results: We identified 2,571 patients with isolated tibial shaft fractures. Of these, 639 (25%) collected a prescription for opioids after the fracture. The median follow-up time was 17 (interquartile range [IQR] 7-27) months. Most patients with opioid prescriptions after fracture were male (61%) and the median age was 45 (16-97) years. The leading mechanism of injury was fall on the same level (41%). At 6 and 12 months after fracture, 21% (95% CI 17-24) and 14% (11-17) were still being treated with opioids. Multiple Cox regression-analysis (adjusted for age, sex, type of treatment, and mechanism of injury) revealed that older patients (age >50 years) were more likely to end opioid prescriptions (Hazard ratio 1.5 [95% CI 1.3-1.9]). During follow-up, the frequency of patients on moderate and high doses declined. Comparison of the daily morphine equivalent dose among individuals who both had prescriptions during the first 3 months and the 6th month indicated that the majority of these patients (11/14) did not have dose escalations.Conclusions: We did not see any signs in registry-data of major dose escalations over time in patients on potent opioids after tibial shaft fractures.
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| 3. |
- Bahmanyar, Shahram, et al.
(författare)
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Maternal smoking during pregnancy, other prenatal and perinatal factors, and the risk of Legg-Calvé-Perthes disease
- 2008
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Ingår i: Pediatrics. - : American Academy of Pediatrics. - 0031-4005 .- 1098-4275. ; 122:2, s. e459-e464
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The causes of Legg-Calvé-Perthes disease are largely unknown, but this pediatric disease seems to result from interruption of the blood supply to the proximal femur and is considered a vascular disease. Because maternal smoking during pregnancy influences fetal development and is associated with cardiovascular diseases in offspring, we hypothesized that this exposure is a risk for Legg-Calvé-Perthes disease and also investigated other markers of impaired fetal development and early-life exposures.MATERIALS AND METHODS: The Swedish Inpatient Register identified 852 individuals with a diagnosis of Legg-Calvé-Perthes disease from 1983 to 2005, individually matched by year of birth, age, sex, and region of residence with 4432 randomly selected control subjects. Linkage with the Swedish Medical Birth Register provided information on prenatal factors, including maternal smoking. Conditional logistic regression examined associations of maternal smoking during pregnancy and the other measures with the risk of Legg-Calvé-Perthes disease in offspring, adjusted for socioeconomic index and other potential confounding factors.RESULTS: Maternal smoking during pregnancy was associated with an increased Legg-Calvé-Perthes disease risk, and heavy smoking was associated with a risk increase of almost 100%. Very low birth weight and cesarean section were independently associated with approximately 240% and 36% increases in the risk of Legg-Calvé-Perthes disease, respectively.CONCLUSION: Maternal smoking during pregnancy and other factors indicated by impaired fetal development may be associated with an increased risk of Legg-Calvé-Perthes disease.
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| 4. |
- Dahlstrand, Henrik, et al.
(författare)
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Comparison of metal ion concentrations and implant survival after total hip arthroplasty with metal-on-metal versus metal-on-polyethylene articulations : a 16-year follow-up of a prospective randomized study
- 2017
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 88:5, s. 490-495
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose - Large metal-on-metal (MoM) articulations are associated with metal wear and corrosion, leading to increased metal ion concentrations and unacceptable revision rates. There are few comparative studies of 28-mm MoM articulations with conventional metal-on-polyethylene (MoP) couplings. We present a long-term follow-up of a randomized controlled trial comparing MoM versus MoP 28-mm articulations, focused on metal ions and implant survival. Patients and methods - 85 patients with a mean age of 65 years at surgery were randomized to a MoM (Metasul) or a MoP (Protasul) bearing. After 16 years, 38 patients had died and 4 had undergone revision surgery. 13 patients were unavailable for clinical follow-up, leaving 30 patients (n = 14 MoM and n = 16 MoP) for analysis of metal ion concentrations and clinical outcome. Results - 15-year implant survival was similar in both groups (MoM 96% [95% CI 88-100] versus MoP 97% [95% CI 91-100]). The mean serum cobalt concentration was 4-fold higher in the MoM (1.5 mu g/L) compared with the MoP cohort (0.4 mu g/L, p < 0.001) and the mean chromium concentration was double in the MoM (2.2 mu g/L) compared with the MoP cohort (1.0 mu g/L, p = 0.05). Mean creatinine levels were similar in both groups (MoM 93 mu mol/L versus MoP 92 mu mol/L). Harris hip scores differed only marginally between the MoM and MoP cohorts. Interpretation - This is the longest follow-up of a randomized trial on 28-mm MoM articulations, and although implant survival in the 2 groups was similar, metal ion concentrations remained elevated in the MoM cohort even in the long term.
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| 5. |
- Hailer, Nils P., et al.
(författare)
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Dual-mobility cups for revision due to instability are associated with a low rate of re-revisions due to dislocation.
- 2012
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Ingår i: Acta orthopaedica. - : Medical Journals Sweden AB. - 1745-3682 .- 1745-3674. ; 83:6, s. 566-571
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose Revision total hip arthroplasty (THA) due to recurrent dislocations is associated with a high risk of persistent instability. We hypothesized that the use of dual-mobility cups would reduce the risk of re-revision due to dislocation after revision THA. Patients and methods 228 THA cup revisions (in 228 patients) performed due to recurrent dislocations and employing a specific dual-mobility cup (Avantage) were identified in the Swedish Hip Arthroplasty Register. Kaplan-Meier survival analysis was performed with re-revision due to dislocation as the primary endpoint and re-revision for any reason as the secondary endpoint. Cox regression models were fitted in order to calculate the influence of various covariates on the risk of re-revision. Results 58 patients (25%) had been revised at least once prior to the index cup revision. The surgical approach at the index cup revision was lateral in 99 cases (44%) and posterior in 124 cases (56%). Median follow-up was 2 (0-6) years after the index cup revision, and by then 18 patients (8%) had been re-revised for any reason. Of these, 4 patients (2%) had been re-revised due to dislocation. Survival after 2 years with the endpoint revision of any component due to dislocation was 99% (95% CI: 97-100), and it was 93% (CI: 90-97) with the endpoint revision of any component for any reason. Risk factors for subsequent re-revision for any reason were age between 50-59 years at the time of the index cup revision (risk ratio (RR) = 5 when compared with age > 75, CI: 1-23) and previous revision surgery to the relevant joint (RR = 1.7 per previous revision, CI: 1-3). Interpretation The risk of re-revision due to dislocation after insertion of dual-mobility cups during revision THA performed for recurrent dislocations appears to be low in the short term. Since most dislocations occur early after revision THA, we believe that this device adequately addresses the problem of recurrent instability. Younger age and prior hip revision surgery are risk factors for further revision surgery. However, problems such as potentially increased liner wear and subsequent aseptic loosening may be associated with the use of such devices in the long term.
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| 6. |
- Wedin, Rikard, et al.
(författare)
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Complications and survival after surgical treatment of 214 metastatic lesions of the humerus
- 2012
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Ingår i: Journal of Shoulder and Elbow Surgery. - : Elsevier BV. - 1058-2746 .- 1532-6500. ; 21:8, s. 1049-1055
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Tidskriftsartikel (refereegranskat)abstract
- Background: The humerus is the second most common long-bone site of metastatic bone disease. We report complications, risk factors for failure, and survival of a large series of patients operated on for skeletal metastases of the humerus. Materials and methods: This study was based on 208 patients treated surgically for 214 metastatic lesions of the humerus. Reconstructions were achieved by intramedullary nails in 148, endoprostheses in 35, plate fixation in 21, and by other methods in 10. Results: The median age at surgery was 67 years (range, 29-87 years). Breast cancer was the primary tumor in 31%. The overall failure rate of the surgical reconstructions was 9%. The reoperation rate was 7% in the proximal humerus, 8% in the diaphysis, and 33% in the distal part of the bone. Among 36 operations involving an endoprosthesis, 2 were failures (6%) compared with 18 of 178 osteosynthetic devices (10%). In the osteosynthesis group, intramedullary nails failed in 7% and plate fixation failed in 22%. Multivariate Cox regression analysis showed that prostate cancer was associated with an increased risk of failure after surgery (hazard ratio, 7; P < 0.033). The cumulative survival after surgery was 40% (95% confidence interval [CI] 34-47) at 1 year, 21% (95% CI, 15-26) at 2 years, and 16% (95% CI, 12-19) at 3 years. Conclusions: Our method of choice is the cemented hemiprosthesis for pathologic proximal humeral fractures and interlocked intramedullary nail for lesions in the diaphysis. Pathologic fractures in the distal humerus are uncommon and associated with a very high reoperation rate. Level of evidence: Level IV, Case Series, Treatment Study. (C) 2012 Journal of Shoulder and Elbow Surgery Board of Trustees.
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| 7. |
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| 8. |
- Weiss, Rüdiger J., et al.
(författare)
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Decreasing incidence of tibial shaft fractures between 1998 and 2004 : information based on 10,627 Swedish inpatients
- 2008
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Ingår i: Acta Orthopaedica. - Lund : Taylor & Francis. - 1745-3674 .- 1745-3682. ; 79:4, s. 526-533
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose There is a lack of national epidemiological data on the characteristics of patients with tibial shaft fractures. We therefore analyzed data on Swedish patients with tibial shaft fractures in this nationwide population study based on data from 1998 through 2004. Methods Data on all patients with tibial shaft fractures were extracted from the Swedish National Hospital Discharge Register. Results We identified 10,627 hospital admissions for tibial shaft fractures, corresponding to an annual incidence rate of 17 per 100,000 person-years (pyr). The number of hospital admissions decreased by 12% during the period 1998-2004, mostly from a reduction in male incidence. The median (SD) age at admission was 28 (22) years for men and 51 (26) years for women. The two major mechanisms of injury were falls on the same level (48%) and transport accidents (21%). Surgical procedures were dominated by osteosynthesis with nail (48%), followed by closed reduction and plaster cast (27%), and external fixation (12%). 12% of all tibial shaft fractures were classified as open, corresponding to an incidence rate of 2.3 per 100,000 pyr, which declined during 1998-2004. Interpretation This nationwide study of tibial shaft fractures shows a falling off of fracture incidence, a finding that can be used to advantage by healthcare providers. In a recent review, the annual incidence of tibial shaft fractures was reported to be 22 per 100,000 inhabitants (Court-Brown and Caesar 2006). To date, rather few epidemiological studies have been undertaken to examine the incidence of this injury (Knowelden et al. 1964, Bengner et al. 1990, Donaldson et al. 1990, Court-Brown and McBirnie 1995, Emami et al. 1996, Singer et al. 1998, van Staa et al. 2001), and with varying results. Most of the earlier epidemiological studies were retrospective or case series from single hospitals, and prior to the present study no analyses on a nationwide basis had been undertaken.Basic epidemiological data on frequency and distribution, mechanisms of injury, surgical procedures, and on temporal variations are of importance in assisting the planning and delivery of healthcare. The purpose of this investigation was to provide an update on incidence, admissions, causes of fracture, and operation of these fractures on a nationwide basis in Sweden during the period 1998-2004.
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| 9. |
- Weiss, Rüdiger J., et al.
(författare)
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Gait pattern in rheumatoid arthritis
- 2008
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Ingår i: Gait & Posture. - Clare, Ireland : Elsevier. - 0966-6362 .- 1879-2219. ; 28:2, s. 229-234
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to analyse kinematic and kinetic gait changes in rheumatoid arthritis (RA) patients in comparison to healthy controls and to examine whether levels of functional disability (Health Assessment Questionnaire (HAQ)-scores) were associated with gait parameters. Using a three-dimensional motion analysis system, kinematic and kinetic gait parameters were measured in 50 RA patients and 37 healthy controls. There was a significant reduction in joint motions, joint moments and work in the RA cohort compared with healthy controls. The following joint motions were decreased: hip flexion-extension range (Delta6 degrees ), hip abduction (Delta4 degrees ), knee flexion-extension range (Delta8 degrees ) and ankle plantarflexion (Delta10 degrees ). The following joint moments were reduced: hip extensor (Delta0.30Nm/kg) and flexor (Delta0.20Nm/kg), knee extensor (Delta0.11Nm/kg) and flexor (Delta0.13Nm/kg), and ankle plantarflexor (Delta0.44Nm/kg). Work was lower in hip positive work (Delta0.07J/kg), knee negative work (Delta0.08J/kg) and ankle positive work (Delta0.15J/kg). Correlations were fair although significant between HAQ and hip flexion-extension range, hip abduction, knee flexion-extension range, hip abductor moment, stride length, step length and single support (r=-0.30 to -0.38, p<0.05). Our findings suggest that RA patients have overall less joint movement and specifically restricted joint moments and work across the large joints of the lower limbs during walking than healthy controls. There were only fair associations between levels of functional disability and gait parameters. The findings of this study help to improve the understanding how RA affects gait changes in the lower limbs.
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| 10. |
- Weiss, Rüdiger J., et al.
(författare)
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Increased early mortality and morbidity after total hip arthroplasty in patients with socioeconomic disadvantage: a report from the Swedish Hip Arthroplasty Register
- 2019
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Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 1745-3682. ; 90:3, s. 264-269
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose — Socioeconomic status is associated with the outcome of major surgery. We investigated the association of socioeconomic status with the risk of early mortality and readmissions after primary total hip arthroplasty (THA). Patients and methods — We obtained information on income, education, immigration, and cohabiting status as well as comorbidities of 166,076 patients who underwent primary THA due to primary osteoarthritis (OA) from the Swedish Hip Arthroplasty Register, the Swedish National Inpatient Register and Statistics Sweden. Multivariable Cox regression models were fitted to estimate the adjusted risk of mortality or readmissions within 90 days after index surgery. Results — Compared with patients on a low income, the adjusted risk of 30-day mortality was considerably lower in patients on a high income (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3–0.7) and in those on a medium income (HR 0.7, CI 0.6–0.9). Similar risk reductions were found for the endpoint 90-day mortality. Patients with a high income had a lower adjusted risk of readmission for cardiovascular reasons than those with a low income (HR 0.7, CI 0.6–0.9), as had those with a higher level of education (adjusted HR 0.7, CI 0.6–0.9). Patients with higher socioeconomic status had a lower degree of comorbidities than socioeconomically disadvantaged patients. However, adjusting for socioeconomic confounders in multivariable models only marginally influenced the predictive ability of the models, as expressed by their area under the curve. Interpretation — Income and level of education are strongly associated with early mortality and readmissions after primary THA, and both parameters are closely connected to health status. Since adjustment for socioeconomic confounders only marginally improved the predictive ability of multivariable regression models our findings indicate that comorbidities may under certain circumstances serve as an acceptable proxy measure of socioeconomic background.
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