Search

Sahar Moeini,1 Jeppe V Rasmussen,1 Tobias W Klausen,2 Stig Brorson1 1Department of Orthopedic Surgery, 2Department of Hematology, Herlev Hospital, Herlev, Denmark Purpose: The Western Ontario Osteoarthritis of the Shoulder (WOOS) index is a disease-specific, patient-reported, 19-question survey that measures the quality of life among patients with osteoarthritis (OA). The purpose of this study was to validate the Danish version of WOOS for OA and fractures (FRs) using modern test theory.Patients and methods: The study included 1,987 arthroplasties in 1,943 patients that were reported to the Danish Shoulder Arthroplasty Register between 2006 and 2011. These included 847 OA and 1,140 FR cases.Results: Principal component analysis indicated the unidimensionality of WOOS. The person reliabilities showed a floor-ceiling effect, indicating that a dichotomy was the best fit for the WOOS scale. For OA, WOOS showed good reliability (item and person reliability of 0.98 and 0.76) and good targeting, with a person mean of -0.56 logits. FR also showed good targeting (person mean of -0.08) and good reliability (item and person reliabilities of 1.00 and 0.86, respectively). All WOOS items fit well with the OA sample except items 5 and 6 (pertaining to grinding and the influence of weather). In addition, item 6 showed signs of degrading the scale with an outfit mean square of 2.46. Only item 6 showed a misfit for FR with no sign of scale degradation. The residual principal component analysis confirmed the unidimensionality of FR but not OA. Six items displayed clinically significant differential item functioning between OA and FR.Conclusion: Rasch analysis showed that WOOS had a good fit with the Rasch model when used as a dichotomous scale for OA and FR. However, the results were valid only when WOOS was divided into two categories with a threshold of 950 (50% of the maximum score). For the use of WOOS in future clinical research, we recommend that a dichotomous score be reported as a measure of clinical failure in OA and FR. Keywords: shoulder arthroplasty, modern test theory, patient-reported outcome measure, questionnaire, quality of life

Jeppe V Rasmussen,1 John Jakobsen,2 Bo S Olsen,1 Stig Brorson1 1Department of Orthopedic Surgery, Herlev University Hospital, Herlev, Denmark; 2Department of Orthopedic Surgery, Aalborg University Hospital, Thisted, Denmark Background and purpose: The Western Ontario Osteoarthritis of the Shoulder (WOOS) index is a patient-reported, disease-specific questionnaire for the measurement of the quality-of-life in patients with osteoarthritis. The purpose of this study was to describe the process used to translate the WOOS into Danish and to test the translation in a Danish population, in terms of validity, reliability, and responsiveness. Material and methods: The translation of the WOOS was done according to international standardized guidelines. The psychometric properties were tested in 20 consecutive patients. The eligibility criteria were: a diagnosis of osteoarthritis without symptomatic rotator cuff pathology and treated with primary shoulder replacement. Patients were excluded only in the case of other pathology of the upper extremity or in the case of cognitive or linguistic impairment compromising the ability to complete the questionnaires. Results: The Pearson's correlation coefficient between the WOOS and the Constant-Murley score (CMS), preoperatively was 0.62 (P = 0.004) and the correlation between the changes of score for the WOOS and CMS was 0.73 (P < 0.001). The correlation coefficient between the WOOS and the CMS, SF-36, and the Oxford Shoulder Score postoperatively was 0.82 (P < 0.001), 0.48 (P = 0.03), and 0.82 (P < 0.001), respectively. There were no floor and ceiling effects. The Cronbach's alpha was 0.98. The intraclass correlation coefficient between test and retest was 0.96. The standardized response mean was 1.41, and effect size was 2.32. Conclusion: We have shown that the Danish version of the WOOS, translated according to international standardized guidelines, has substantial statistical and clinical psychometric properties at the same level as was described for the original version. Keywords: outcome assessment, cross-cultural adaption, questionnaire

Presents an overview of a study that measured the energy distribution of hot electrons in high-field stressed amorphous silicon dioxide films using a vacuum emission technique. Electron transport properties of silicon oxide; Measurement of energy distribution of the electrons ejected into vacuum using an Einzel electron lens and retarding potential system; Electric field dependence of the energy distribution; Effect of the metal gate.

Focuses on a study which described the light output properties of single mode lasers having capacity dimensions on the order of the emitted wavelength. Discussion on emission rate enhancement; Methodology of the study; Results and discussion.

Discusses a study on electron heating in silicon dioxide and off-stoichiometric silicon dioxide films. Details on experimental techniques used in the study; Demonstration of the gradual heating of electronic carrier distributions; Treatment of the relationship of electron heating to electron trapping, positive charge generation, interface state creation and dielectric breakdown.