Results of neutron time-of-flight measurements are commonly used to parameterize neutron induced reaction cross sections in the resonance region based on the R-matrix reaction theory. Reaction yields ...or transmission as well as their covariance information are derived starting from measured counting spectra. They are then used in a least squares adjustment for obtaining model parameters. In this paper, a compact formalism is presented to propagate both the correlated and uncorrelated uncertainty components. Full information on the origin of each correlated component of the covariance matrix is maintained. This is particularly important in order to avoid a bias on the model parameters through a phenomenon known as Peelle's Pertinent Puzzle (PPP). This compact formalism was implemented into the data reduction code AGS (Analysis of Geel Spectra).
Introduction
Anterior knee pain (AKP) is a frequent complication after total knee arthroplasty (TKA). Patelloplasty, defined as reshaping the patella for optimal tracking in the trochlea, has been ...proposed to reduce the rate of this complication in patellar retaining implants. Aim of this study was to analyze the available literature regarding the outcomes of patelloplasty and to assess its methodological quality.
Materials and methods
A comprehensive review of the English literature was performed using the keywords “total knee arthroplasty”, “patelloplasty” and “patellaplasty” with no limit regarding the year of publication. All the selected articles were evaluated with the Coleman score.
Results
Seven full text articles were retrieved. The initial cohort included 461 knees in the study groups and 465 in the control groups. At an average FU of 70.6 months 447 knees were reviewed in the study group and 447 in the control groups. The global rate of AKP after patelloplasty was 11.3 % which compared to 7.9 % in the patella resurfacing control group. No signs of specific patellar complications due to patelloplasty were reported. Average Coleman score was 66.9.
Conclusion
Most of the literature has barely sufficient methodological quality. Patelloplasty aims at reducing patellar thickness and improve its tracking with TKA. This procedure is a safe and easy option with no reported adverse effects. In the included studies, outcome seemed to be superior in comparison with isolated osteophyte removal and denervation with a lower rate of AKP. The included studies, however, report a lower rate of AKP following TKA with patellar resurfacing. Patelloplasty may have the potential to improve the outcome of patellar retaining implants.
Level of evidence
4, systematic review.
Accurate neutron induced fission cross section of 240Pu and 242Pu are required in view of making nuclear technology safer and more efficient to meet the upcoming needs for the future generation of ...nuclear power plants (GEN-IV). The probability for a neutron to induce such reactions figures in the NEA Nuclear Data High Priority Request List 1. A measurement campaign to determine neutron induced fission cross sections of 240Pu and 242Pu at 2.51 MeV and 14.83 MeV has been carried out at the 3.7 MV Van De Graaff linear accelerator at Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig. Two identical Frisch Grid fission chambers, housing back to back a 238U and a APu target (A = 240 or A = 242), were employed to detect the total fission yield. The targets were molecular plated on 0.25 mm aluminium foils kept at ground potential and the employed gas was P10. The neutron fluence was measured with the proton recoil telescope (T1), which is the German primary standard for neutron fluence measurements. The two measurements were related using a De Pangher long counter and the charge as monitors. The experimental results have an average uncertainty of 3–4% at 2.51 MeV and for 6–8% at 14.81 MeV and have been compared to the data available in literature.
Introduction
The aim of the present study was to determine the incidence and type of complications during and after hip arthroscopy as well as the effect of the surgeon’s learning curve on the ...occurrence of complications. We expect that the currently reported prevalence especially of minor complications is likely to be underreported in most retrospective series based on chart analysis.
Materials and methods
The study included all consecutive patients who underwent hip arthroscopy between 2006 and 2014 at a minimum follow-up of 6 weeks starting with the first patient undergoing hip arthroscopy at the institution. Patient outcome was evaluated using the WOMAC score, VAS for pain, SF-36 questionnaire and the hip-outcome score. Additionally, intra- and postoperative complications were recorded via a questionnaire and additional review of patient files.
Results
We identified 529 patients who underwent hip arthroscopy between 2006 and 2014. Complete data could be gathered from 485 patients (91.7%). Major complications occurred in three patients (0.6%; fractures of the femoral neck requiring surgical treatment in one case). Minor complications that did not require further intervention were self-limiting postoperative temporary neurapraxia, hematoma, self-limiting dyspareunia, deep vein thrombosis and impaired wound healing, with hematoma and temporary paresthesia due to traction neurapraxia being the most common ones (22.5 and 16.4% respectively). The overall re-operation rate was 15.7% with conversion to total hip arthroplasty being the most common (11.9%).
Conclusions
The overall major complication rate was low and thus hip arthroscopy can be rated as a safe procedure. But minor complications such as hematoma and temporary paresthesia due to traction neurapraxia are common and currently underreported. Surgeons’ learning curves show a reduction of major complications once 60 procedures per surgeon per year is surpassed.
Malignant degeneration in association with orthopaedic implants is a known but rare complication. To our knowledge, no case of osseous malignant fibrous histiocytoma after anterior cruciate ligament ...reconstruction is reported in the literature.
We report a 29-year-old male Turkish patient who presented with severe pain in the operated knee joint 40 months after arthroscopic anterior cruciate ligament reconstruction. X-ray and MR imaging showed a large destructive tumor in the medial femoral condyle. Biopsy determined a malignant fibrous histiocytoma. After neoadjuvant chemotherapy, wide tumor resection and distal femur reconstruction with a silver-coated non-cemented tumor knee joint prosthesis was performed. Adjuvant chemotherapy was continued according to the EURAMOS 1 protocol.
Though secondary malignant degeneration after orthopaedic implants or prostheses is not very likely, the attending physician should take this into consideration, especially if symptoms worsen severely over a short period of time.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Introduction
Tibial component design and positioning contribute more to patient satisfaction than previously realized. A surgeon needs to decide on the size and rotation, bearing in mind that ...coverage should be as high as possible, whilst malrotation and overhang should be avoided. No study investigates the impact of each of these components on clinical outcomes in a single cohort.
Materials and methods
This is a retrospective analysis of 1-year postoperative outcomes measured with the Knee Injury and Osteoarthritis Outcome (KOOS) Score, as well as a previously validated rotational CT protocol. Coverage, rotation from Insall’s axis, and overhang of an asymmetric tibial baseplate were measured, and positive and negative correlations to clinical outcomes were calculated.
Results
A total of 499 knees were analyzed. Patient average age was 68.4 years. Rotation within 7° internal and 5° external from Insall’s axis was a “safe zone”. Mean coverage was 76%. A total of 429 knees (94%) had a coverage of at least 70% and 102 knees (22%) greater than 80%. Overhang was detected in 23% of the cohort. Increased coverage was correlated to increased KOOS score and overhang correlated with a decreased KOOS score (
p
= 0.008).
Conclusions
This study demonstrates the individual role of three aspects of tibial component implantation properties in postoperative pain and short-term functional outcomes. Upsizing to the point of overhang with rotational tolerance of 7° internal and 3° external to Insall’s axis demonstrates best patient reported outcomes. Overhang decreases the clinical outcome by the same margin as loss of 16% of coverage.
Purpose
In this study, the total blood loss, transfusion rate and number of transfused blood units in patients with different indications for shoulder arthroplasty: primary, fracture and secondary ...were compared. Risk factors for bleeding and transfusion were analysed.
Methods
Medical records and the database of the institution’s blood bank from 527 patients that received shoulder arthroplasty were analysed retrospectively. This study included 419 patients that were divided in three different groups: primary (
n
= 278), fracture (
n
= 110) and secondary (following prior osteosynthesis;
n
= 31) shoulder arthroplasty. The demographic and clinical data were collected. The total blood loss (TBL) was calculated and transfusions recorded.
Results
The transfusion rate and mean amount of transfused blood units (BU) were higher in fracture (32.7% and 0.69BU,
p
< 0.01) and secondary arthroplasty (35.5% and 0.97BU,
p
< 0.01) than in primary arthroplasty (12.6% and 0.28BU). The overall transfusion rate was 19.6% at a mean TBL of 370 ml. However, patients with primary arthroplasty experienced significantly higher total blood loss than those after fracture arthroplasty (
p
< 0.01). Longer surgery time and male sex are significant risk factors for elevated blood loss. The pre-operative use of vitamin K antagonist, cemented arthroplasty, high BMI, coronary heart disease and ASA score > 2 are relevant risk factors for blood transfusion.
Conclusion
The most important susceptible factor that affects the TBL is the surgery time. Transfusion rates are higher in patients with fracture arthroplasty than after primary arthroplasty.
Accurate nuclear-data needs in the fast-neutron-energy region have been recently addressed for the development of next generation nuclear power plants (GEN-IV) by the OECD Nuclear Energy Agency ...(NEA). This sensitivity study has shown that of particular interest is the 242Pu(n,f) cross section for fast reactor systems. Measurements have been performed with quasi-monoenergetic neutrons in the energy range from 15 MeV to 20 MeV produced by the Van de Graaff accelerator of the JRC-Geel. A twin Frisch-grid ionization chamber has been used in a back-to-back configuration as fission fragment detector. The 242Pu(n,f) cross section has been normalized to 238U(n,f) cross section data. The results were compared with existing literature data and show acceptable agreement within 5%.
The MetroFission project, a Joint Research Project within the European Metrology Research Program, aims at addressing a number of metrological problems involved in the design of proposed Generation ...IV nuclear reactors. As part of this project a secondary neutron fluence standard is being developed and tested at the neutron time-of-flight facility GELINA of the JRCs Institute for Reference Materials and Measurements. Such a secondary standard will help to arrive at the neutron cross section measurement uncertainties required for the design and safety assessment of new generation power plants and fuel cycles. Such a neutron fluence device contains targets for which the neutron induced cross section is considered to be a standard. A careful preparation and characterization of these samples is an essential part of the development of the secondary standard. In this framework a set of sup.235U targets has been produced by vapour deposition of UF.sub.4 on aluminium backings by IRMMs target preparation laboratory. These targets have been characterized for both their total mass and mass distribution over the sample area. Keywords sup.235U * Characterization * Mass determination * Alpha-particle counting * Metrology
There has been a continuing debate about the overall benefit of cholesterol lowering. We performed a novel meta-analysis of all randomized trials of more than 2 years' duration (n = 35 trials) to ...describe how coronary-heart-disease (CHD), non-CHD, and total mortality are related to cholesterol lowering and to type of intervention.
The analytic approach was designed to separate the effects of cholesterol lowering itself from the other effects of the different types of intervention used. For every 10 percentage points of cholesterol lowering, CHD mortality was reduced by 13% (P < .002) and total mortality by 10% (P < .03). Cholesterol lowering had no effect on non-CHD mortality. Certain types of intervention had specific effects independent of cholesterol lowering. Fibrates (clofibrates, 7 trials; gemfibrozil, 2 trials) increased non-CHD mortality by about 30% (P < .01) and total mortality by about 17% (P < .02). Hormones (estrogen, 2 trials; dextrothyroxin, 2 trials) increased CHD mortality in men by about 27% (P < .04), non-CHD mortality by about 55% (P < .03), and total mortality by about 33% (P < .01). No specific effects independent of cholesterol lowering were found due to diet (n = 11) or other interventions (resins, 5; niacin, 3; statins, 2; partial ileal bypass, 1).
The results suggest that cholesterol lowering itself is beneficial but that specific adverse effects of fibrates and hormones increase the risk of CHD (hormones only), non-CHD, and total mortality.
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