scholarly journals Determination of Leg Alignment in Hip Osteoarthritis Patients with the EOS® System and the Effect on External Joint Moments during Gait

2020 ◽  
Vol 10 (21) ◽  
pp. 7777
Author(s):  
Stefan van Drongelen ◽  
Hanna Kaldowski ◽  
Benjamin Fey ◽  
Timur Tarhan ◽  
Ayman Assi ◽  
...  
Keyword(s):  
Hip Osteoarthritis ◽  
Contralateral Side ◽  
Knee Adduction Moment ◽  
Strongly Correlated ◽  
Joint Moments ◽  
Femoral Offset ◽  
Leg Alignment ◽  
Hip Kinematics ◽  
Valgus Alignment

The present study considered the entire leg alignment and links static parameters to the external joint moments during gait in patients with hip osteoarthritis. Eighteen patients with unilateral hip osteoarthritis were measured using the EOS® system. Clinical leg alignment and femoral parameters were extracted from the 3D reconstruction of the EOS images. A 3D gait analysis was performed and external knee and hip adduction moments were computed and compared to 18 healthy controls in the same age group. The knee adduction moments of the involved leg were strongly correlated to the femoral offset and the varus/valgus alignment. These parameters alone explained over 50% of the variance in the knee adduction moments. Adding the pelvic drop of the contralateral side increased the model of femoral offset and varus/valgus alignment and explained 78% of the knee adduction moment during the first half of the stance phase. The hip adduction moments were best associated with the hip kinematics and not the leg alignment.

scholarly journals Are changes in radiological leg alignment and femoral parameters after total hip replacement responsible for joint loading during gait?

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Stefan van Drongelen ◽  
Hanna Kaldowski ◽  
Timur Tarhan ◽  
Ayman Assi ◽  
Andrea Meurer ◽  
...  
Keyword(s):  
Total Hip Replacement ◽  
Hip Replacement ◽  
Hip Osteoarthritis ◽  
Frontal Plane ◽  
Healthy Controls ◽  
Varus Alignment ◽  
Joint Moments ◽  
Total Hip ◽  
Leg Alignment ◽  
Shaft Angle

Abstract Background Gait kinematics after total hip replacement only partly explain the differences in the joint moments in the frontal plane between hip osteoarthritis patients after hip replacement and healthy controls. The goal of this study was to determine if total hip replacement surgery affects radiological leg alignment (Hip-Knee-Shaft-Angle, femoral offset, Neck-Shaft-Angle and varus/valgus alignment) and which of these parameters can explain the joint moments, additionally to the gait kinematics. Methods 22 unilateral hip osteoarthritis patients who were scheduled for total hip replacement were included in the study. Preoperatively and 1 year postoperatively all patients had biplanar radiographic examinations and 3D gait analysis. Results The operated leg showed significantly (P < 0.05) more varus (1.1°) as well as a larger femoral offset (+ 8 mm) and a larger Hip-Knee-Shaft-Angle (+ 1.3°) after total hip replacement; however no significant differences in the joint moments in the frontal plane compared to healthy controls were found. The hip moment (first half of stance) and the knee moments (first and second half of stance) were mostly determined by the varus/valgus alignment (29% and respectively 36% and 35%). The combination with a kinematic parameter (knee range of motion, foot progression angle) increased the predictive value for the knee moments. Conclusion In our patient group the joint moments after total hip replacement did not differ from healthy controls, whereas radiological leg alignment parameters changed significantly after the total hip replacement. A combination of these radiological leg parameters, especially the varus alignment, and the deviating kinematics explain the joint moments in the frontal plane during gait after total hip replacement surgery. For surgeons it is important not to create too much of a structural varus alignment by implanting the new hip joint as varus alignment can increase the knee adduction moment and the risk for osteoarthritis of the medial knee compartment. Trial registration This study was retrospectively registered with DRKS (German Clinical Trials Register) under the number DRKS00015053. Registered 1st of August 2018.

scholarly journals Comparison of Gait Symmetry and Joint Moments in Unilateral and Bilateral Hip Osteoarthritis Patients and Healthy Controls

2021 ◽  
Vol 9 ◽  
Author(s):  
S. van Drongelen ◽  
S. Braun ◽  
F. Stief ◽  
A. Meurer
Keyword(s):  
Knee Joint ◽  
Hip Osteoarthritis ◽  
Gait Pattern ◽  
Knee Adduction Moment ◽  
Healthy Controls ◽  
Joint Loading ◽  
Joint Moments ◽  
Gait Kinematics ◽  
Kinetics Of ◽  
Knee Joint Loading

Patients with unilateral hip osteoarthritis show a characteristic gait pattern in which they unload the affected leg and overload the unaffected leg. Information on the gait characteristics of patients with bilateral hip osteoarthritis is very limited. The main purposes of this study were to investigate whether the gait pattern of both legs of patients with bilateral hip osteoarthritis deviates from healthy controls and whether bilateral hip osteoarthritis patients show a more symmetrical joint load compared to unilateral hip osteoarthritis patients. In this prospective study, 26 patients with bilateral hip osteoarthritis, 26 patients with unilateral hip osteoarthritis and 26 healthy controls were included. The three groups were matched for gender, age and walking speed. Patients were scheduled for a unilateral total hip arthroplasty on the more affected/more painful side. All participants underwent a three-dimensional gait analysis. Gait kinematics and gait kinetics of patients and controls were compared using Statistical Parametric Mapping. Corrected for speed, the gait kinematics and kinetics of both legs of patients with bilateral hip osteoarthritis differed from healthy controls. Bilateral patients had symmetrical knee joint loading, in contrast to the asymmetrical knee joint loading in unilateral hip osteoarthritis patients. The ipsilateral leg of the bilateral patients could be included in studies in addition to unilateral hip osteoarthritis patients as no differences were found. Although patients with bilateral hip osteoarthritis show more symmetrical frontal plane knee joint moments, a pathological external knee adduction moment in the second half of stance was present in the ipsilateral leg in patients with unilateral and bilateral hip osteoarthritis. The lateral adjustment of the knee adduction moment may initiate or accelerate progression of degenerative changes in the lateral compartment of the knee.

scholarly journals Towards planning of osteotomy around the knee with quantitative inclusion of the adduction moment: a biomechanical approach

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Margit Biehl ◽  
Philipp Damm ◽  
Adam Trepczynski ◽  
Stefan Preiss ◽  
Gian Max Salzmann
Keyword(s):  
Gait Analysis ◽  
Measurement Data ◽  
Frontal Plane ◽  
Medial Compartment ◽  
Knee Adduction Moment ◽  
In Vivo Measurement ◽  
Force Ratio ◽  
Leg Alignment ◽  
Alignment Angle

Abstract Purpose Despite practised for decades, the planning of osteotomy around the knee, commonly using the Mikulicz-Line, is only empirically based, clinical outcome inconsistent and the target angle still controversial. A better target than the angle of frontal-plane static leg alignment might be the external frontal-plane lever arm (EFL) of the knee adduction moment. Hypothetically assessable from frontal-plane-radiograph skeleton dimensions, it might depend on the leg-alignment angle, the hip-centre-to-hip-centre distance, the femur- and tibia-length. Methods The target EFL to achieve a medial compartment force ratio of 50% during level-walking was identified by relating in-vivo-measurement data of knee-internal loads from nine subjects with instrumented prostheses to the same subjects’ EFLs computed from frontal-plane skeleton dimensions. Adduction moments derived from these calculated EFLs were compared to the subjects’ adduction moments measured during gait analysis. Results Highly significant relationships (0.88 ≤ R2 ≤ 0.90) were found for both the peak adduction moment measured during gait analysis and the medial compartment force ratio measured in vivo to EFL calculated from frontal-plane skeleton dimensions. Both correlations exceed the respective correlations with the leg alignment angle, EFL even predicts the adduction moment’s first peak. The guideline EFL for planning osteotomy was identified to 0.349 times the epicondyle distance, hence deducing formulas for individualized target angles and Mikulicz-Line positions based on full-leg radiograph skeleton dimensions. Applied to realistic skeleton geometries, widespread results explain the inconsistency regarding correction recommendations, whereas results for average geometries exactly meet the most-consented “Fujisawa-Point”. Conclusion Osteotomy outcome might be improved by planning re-alignment based on the provided formulas exploiting full-leg-radiograph skeleton dimensions.

A Comparative Analysis of the Power of Selected European Countries. The Economic Determinants

2021 ◽  
Vol 37 (37) ◽  
pp. 22-42
Author(s):  
Alicja Paluch ◽  
Henryk Spustek
Keyword(s):  
Czech Republic ◽  
Comparative Analysis ◽  
European Countries ◽  
Economic Power ◽  
Strongly Correlated ◽  
The Czech Republic ◽  
Independent Variables ◽  
Economic Sphere ◽  
National Power

The ever-increasing need for in-depth analysis and quantification of the national power, in particular ‘hard’ and ‘soft’ power-generating factors as well as difficulties in identifying a comprehensive and effective method for scientific determination of the national power, have given rise to research in the indicated scientific issues within this article. The presented considerations aim to define the assumptions for a descriptive sub-model that would enable a comparison of Poland’s power in the economic sphere (which is a component of the non-military sphere) with the power of selected European countries. The research hypothesis is that, among the variety of descriptive variables in the economic sphere of the national power, there is a subset of mutually independent variables, at the same time strongly correlated with the national power, which make it possible to define assumptions for the sub-model of the national power. The steps of the research procedure were carried out using the method of system analysis (multi-criteria comparative analysis) and statistical analysis. The research activities undertaken have shown that the factors that are strongly correlated with the national power in the economic area of the European countries adopted for the analysis are: dynamics of industrial production, private sector credit flows and economic freedom index. The comparative analysis carried out demonstrates that the greatest increase in the economic power in the analysed period took place in Germany (0.68). Slightly smaller growth was recorded in the Czech Republic (0.62) and Poland (0.60), while the lowest value of increase was in Romania (0.23). The conducted qualitative comparative analysis of the economic power of selected European countries allowed to conclude that the independent variables identified are crucial for the formation of the economic power of the analysed countries. At the same time, a fairly strong position of the Czech Republic and Poland in relation to the economic power of Germany was found. The performed quantification of the economic power of the European countries provides a basis for the correct determination of changes in the power distribution of political units, assessment of the power and resources held by the state.

scholarly journals Toward Robust and Routine Determination of Mw for Small Earthquakes: Application to the 2020 Mw 5.7 Magna, Utah, Seismic Sequence

2021 ◽  
Author(s):  
James Holt ◽  
Katherine M. Whidden ◽  
Keith D. Koper ◽  
Kristine L. Pankow ◽  
Kevin Mayeda ◽  
...  
Keyword(s):  
Spectral Methods ◽  
Moment Tensor ◽  
Coda Wave ◽  
Strongly Correlated ◽  
Seismic Sequence ◽  
Wave Method ◽  
Direct Wave ◽  
Main Requirement ◽  
Relationship Of

Abstract To better characterize seismic hazard, particularly, for induced seismicity, there is an increasing interest in methods to estimate moment magnitude (Mw) for small earthquakes. Mw is generally preferred over other magnitude types, but, it is difficult to estimate Mw for earthquakes with local magnitude (ML) &lt;3–3.5, using conventional moment tensor (MT) inversion. The 2020 Mww 5.7 Magna, Utah, seismic sequence provides an opportunity to illustrate and evaluate the value of spectral methods for this purpose. Starting with a high-quality seismic catalog of 2103 earthquakes (ML&lt;5.6), we estimate Mw using two independent spectral methods—one based on direct waves, yielding Mw,direct, and the other based on coda waves, yielding Mw,coda. For the direct-wave method, we present a non-parametric (NP) inversion scheme that solves for apparent geometrical spreading, G(R), and site effects (S), similar to other NP procedures that have been used to calibrate regional ML scales. The NP inversion is constrained using Mws derived from MTs for nine events in the Magna sequence. We recover statistically robust and physically reasonable G(R) and S and compute Mw,direct for 635 Magna earthquakes down to ML 0.7. For the coda-wave method, we consider two separate calibration schemes involving previous MT solutions and compute Mw,coda for 311 earthquakes down to ML 1.0. For 280 of the events that were processed with both methods—Mw,direct and Mw,coda—are strongly correlated (r = 0.98), with a mean difference of only 0.05. We compare Mw,direct and Mw,coda with ML and find reasonably good agreement for ML&lt;3.6 with the theoretically predicted relationship of Mw=(2/3)ML+C, in which C is a regional constant. Our results imply that seismic network operators can use spectral-based Mw estimates to replace ML estimates for events with ML≥1.0, and possibly smaller. The main requirement is the existence of a small number of MT solutions for calibration purposes.

scholarly journals Detection of Specific Antinuclear Reactivities in Patients with Negative Anti-nuclear Antibody Immunofluorescence Screening Tests

2002 ◽  
Vol 48 (12) ◽  
pp. 2171-2176 ◽  
Author(s):  
Ilse EA Hoffman ◽  
Isabelle Peene ◽  
Eric M Veys ◽  
Filip De Keyser
Keyword(s):  
Connective Tissue ◽  
Confidence Interval ◽  
Connective Tissue Disease ◽  
Indirect Immunofluorescence ◽  
Connective Tissue Diseases ◽  
Clinical Suspicion ◽  
Screening Tests ◽  
Strongly Correlated ◽  
Nuclear Antigens

Abstract Background: For detection of anti-nuclear antibodies (ANAs) and antibodies to extractable nuclear antigens (ENAs), samples frequently are screened with indirect immunofluorescence (IIF); further determination of anti-ENA antibodies is performed only when the result is positive. However, because anti-ENA reactivities are found in samples with low fluorescence intensities, we determined anti-ENA antibodies in samples with negative IIF and thus calculated the sensitivity of IIF for specific ANAs. Methods: We collected 494 samples consecutively referred by rheumatologists for routine ANA testing. IIF on HEp-2 and HEp-2000 (HEp-2 cells transfected with Ro60 cDNA) and line immunoassay (LIA) for the detection of specific ANAs were performed on all samples. Results: Fluorescence intensities and patterns on HEp-2 were strongly correlated with those on HEp-2000 [Spearman ρ = 0.852 (P &lt;0.001) and 0.838 (P &lt;0.001), respectively]. Sixty-eight of 494 samples were positive on LIA, of which only 72% (confidence interval, 68–76%) were detected with HEp-2 and 75% (confidence interval, 70–78%) with HEp-2000. Of 291 samples negative on both substrates, 12 were positive on LIA. Connective tissue diseases were diagnosed in four of these patients and suspected in at least three others. Conclusion: The HEp-2 and HEp-2000 substrates perform comparably for fluorescence intensities and patterns and for detecting specific ANAs, but some patients with negative IIF show reactivity on LIA. We recommend testing for fine reactivities, regardless of the IIF result, when the clinical suspicion for rheumatic connective tissue disease is high.

Detection of allergen-induced airway hyperresponsiveness in isolated mouse lungs

2006 ◽  
Vol 291 (3) ◽  
pp. L466-L472 ◽  
Author(s):  
Martin Witzenrath ◽  
Birgit Ahrens ◽  
Stefanie M. Kube ◽  
Armin Braun ◽  
Heinz G. Hoymann ◽  
...  
Keyword(s):  
Airway Hyperresponsiveness ◽  
Ex Vivo ◽  
Whole Body ◽  
Strongly Correlated ◽  
Ex Vivo Model ◽  
Isolated Lungs ◽  
Spontaneously Breathing

Airway hyperresponsiveness (AHR) is a hallmark of bronchial asthma. Important features of this exaggerated response to bronchoconstrictive stimuli have mostly been investigated in vivo in intact animals or in vitro in isolated tracheal or bronchial tissues. Both approaches have important advantages but also certain limitations. Therefore, the aim of our study was to develop an ex vivo model of isolated lungs from sensitized mice for the investigation of airway responsiveness (AR). BALB/c mice were sensitized by intraperitoneal ovalbumin (Ova) and subsequently challenged by Ova inhalation. In vivo AR was measured in unrestrained animals by whole body plethysmography after stimulation with aerosolized methacholine (MCh) with determination of enhanced pause ( Penh). Twenty-four hours after each Penh measurement, airway resistance was continuously registered in isolated, perfused, and ventilated lungs on stimulation with inhaled or intravascular MCh or nebulized Ova. In a subset of experiments, in vivo AR was additionally measured in orotracheally intubated, spontaneously breathing mice 24 h after Penh measurement, and lungs were isolated further 24 h later. Isolated lungs of allergen-sensitized and -challenged mice showed increased AR after MCh inhalation or infusion as well as after specific provocation with aerosolized allergen. AR was increased on days 2 and 5 after Ova challenge and had returned to baseline on day 9. AHR in isolated lungs after aerosolized or intravascular MCh strongly correlated with in vivo AR. Pretreatment of isolated lungs with the β2-agonist fenoterol diminished AR. In conclusion, this model provides new opportunities to investigate mechanisms of AHR as well as pharmacological interventions on an intact organ level.

Characteristics of sagittal spine–pelvis–leg alignment in patients with severe hip osteoarthritis

2014 ◽  
Vol 24 (6) ◽  
pp. 1228-1236 ◽  
Author(s):  
Wen-Jie Weng ◽  
Wei-Jun Wang ◽  
Ming-Da Wu ◽  
Zhi-Hong Xu ◽  
Lei-Lei Xu ◽  
...  
Keyword(s):  
Hip Osteoarthritis ◽  
Leg Alignment
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