statistical evaluation
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Structured and complex data can be found in many applications in research and development, and also in industrial practice. We developed a methodology for describing the structured data complexity and applied it in development and industrial practice. The methodology uses fractal dimension together with statistical tools and with software modification is able to analyse data in a form of sequence (signals, surface roughness), 2D images, and dividing lines. The methodology had not been tested for a relatively large collection of data. For this reason, samples with structured surfaces produced with different technologies and properties were measured and evaluated with many types of parameters. The paper intends to analyse data measured by a surface roughness tester. The methodology shown compares standard and nonstandard parameters, searches the optimal parameters for a complete analysis, and specifies the sensitivity to directionality of samples for these types of surfaces. The text presents application of fractal geometry (fractal dimension) for complex surface analysis in combination with standard roughness parameters (statistical tool).
PURPOSE OF THE STUDY The aim of this prospective randomised study was to compare and statistically analyse two methods of condylar twist angle (CTA) measurement in total knee arthroplasty in order to assess their applicability in routine practice. MATERIAL AND METHODS The study included 238 patients with 256 sites undergoing total knee arthroplasty (TKA) in the period from January 2009 to May 2011. There were 93 men (nine with bilateral TKA) and 145 women (nine with bilateral TKA) with an average age of 69.3 years and a range of 47 to 88 years. The implants NexGen (Zimmer) and ADVANCE? Medial-Pivot Knee (Wright) were used. In each patient, CTA was measured before surgery by the radiologist on a multidetector CT SOMATOM 64 (Siemens) using the Yoshioki method. The other CTA measurement was made intra-operatively by the surgeon using our modification of the Hofmann method which involved the identification of a reference line for optimal rotational alignment of the femoral component. A STATISTICA 9.0 software package was used for statistical analysis. In addition to basic statistical data, selected data were presented in graphical forms as Box and Whisker's plots and histograms. Changes in CTA and differences between the groups were evaluated using the Wilcoxon signed-rank test. Relationships among the variables were studied using Spearman's correlation coefficient. RESULTS The statistical analysis showed that the pre-operative CTA value obtained from CT scans was, on the average, higher by 0.5 degrees than the value from intra-operative measurement, as assessed at the level of significance p = 0.001 (signed-rank test). The intra-individual variability was lower than the inter-individual one (14.4% and 30.8%, respectively). This means that both methods are suitable for CTA measurement in the knee joint replacement procedures. Spearman's correlation coefficient was 0.6, which is the value of medium strong correlation. The post-operative CTA assessed on CT scans was in the range of 0 to 2 degrees in 87.5% of the patients. Both the pre-operative and intra-operative CTA values were significantly higher in women than in men (Wilcoxon two-sample test). There was no statistical difference between the left and the right side. DISCUSSION Malrotation of the femoral component is one of the causes leading to patellar subluxation and pain in the front part of the knee. The post-operative CTA value should be zero. Optimal rotational alignment of the femoral component varies with each patient; in our study it was found in the range of 0 to 7 degrees on the basis of CTA values. We do not recommend 7 degrees of external rotation to be exceeded because of the risk associated with balancing the flexion gaps; nor do we recommend to set internal rotation of the femoral component for the risk of patellar complications. The difference of 0.5 degree found in the CTA value between the two measuring methods can be explained by individual differences in the anatomy of the medial epicondylar region, and by the use of only selected whole numbers (0, 3, 5, 7) in intra-operative measurements. This difference does not play any role in routine surgical procedures. CONCLUSIONS The statistical evaluation of the results of CTA measurement with the two methods showed that both were equally suitable for routine total knee arthroplasty. The results of intra-operative CTA measurements are comparable with those obtained on CT scans; in addition, the intra-operative method is less expensive and eliminates exposure of the patient to radiation. CT-based CTA measurements are useful in the patients with chronic problems afterTKA in whom femoral component malrotation needs to be either confirmed or ruled out.
- Klíčová slova
- CTA, condylar twist angle, Advance Medial - Pivot Knee, NexGen,
- MeSH
- chirurgické operační výkony metody využití MeSH
- financování organizované MeSH
- interpretace statistických dat MeSH
- kolenní kloub chirurgie patofyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- peroperační péče statistika a číselné údaje využití MeSH
- počítačová rentgenová tomografie statistika a číselné údaje MeSH
- prospektivní studie MeSH
- protézy a implantáty využití MeSH
- protézy kolene statistika a číselné údaje využití MeSH
- reprodukovatelnost výsledků MeSH
- rotace škodlivé účinky MeSH
- rozsah kloubních pohybů MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- výsledek terapie MeSH
- výsledky a postupy - zhodnocení (zdravotní péče) statistika a číselné údaje MeSH
- zobrazování trojrozměrné MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři nad 80 let MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- randomizované kontrolované studie MeSH
- srovnávací studie MeSH
V článku jsou prezentovány základní statistické ukazatele z oblasti posuzování zdravotního stavu pro účely invalidity za rok 2015 i souhrnně za období uplynulých pěti let. Poukazuje též na onemocnění, která jsou nejčastějšími příčinami vzniku jednotlivých stupňů invalidity. Vzhledem k faktu, že uznání invalidity zpravidla předchází dočasná pracovní neschopnost, jsou uvedeny i některé související údaje z této oblasti.
The article presents basic statistical indices in the area of assessment of health state for the sake of invalidity in 2015 as well as a survey for the period of the last five years. Attention is also drawn to diseases, which most frequently cause individual degrees of invalidity. Considering the fact that invalidity state is granted or acknowledged is mostly preceded by temporary incapacity to work, certain associated data from the area are listed.
- Klíčová slova
- lékařská posudková služba, dočasná pracovní neschopnost, invalidita,
- MeSH
- interpretace statistických dat MeSH
- lidé MeSH
- posuzování pracovní neschopnosti * MeSH
- pracovní neschopnost statistika a číselné údaje trendy MeSH
- sociální zabezpečení MeSH
- ukazatele zdravotního stavu MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- přehledy MeSH
- Geografické názvy
- Česká republika MeSH
- MeSH
- dospělí MeSH
- finanční podpora výzkumu jako téma MeSH
- fraktury vřetenní kosti epidemiologie etiologie klasifikace MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- senioři MeSH
- statistika jako téma MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- přehledy MeSH
- srovnávací studie MeSH
- MeSH
- hemokoagulace MeSH
- lidé MeSH
- referenční hodnoty MeSH
- statistika jako téma metody MeSH
- Check Tag
- lidé MeSH
... He is also Head of the Statistics Laboratory at the Center for Research in Economics and Statistics ( ... ... He has served as associate editor for the Annals of Statistics and the Journal of the American Statistical ... ... and Executive Editor of Statistical Science. ... ... He is a fellow of the Institute of Mathematical Statistics and the American Statistical Association, ... ... and an elected fellow of the International Statistical Institute. ...
Springer texts in statistics
2nd ed. xxx, 645 s., grafy
