Lack of blinded outcome assessors in randomized trials with subjective time-to-event outcomes causes high risk of observer bias. Nonblinded outcome assessors typically favour the experimental intervention, exaggerating the hazard ratio by an average of approximately 27%; but in special situations, nonblinded outcome assessors favour control interventions, inducing a comparable degree of observer bias in the reversed direction.

No abstract

The Danish Shoulder Arthroplasty Registry (DSR) was established in 2004. Data are reported electronically by the surgeons. Patient-reported outcome is collected 10–14 months postoperatively using the Western Ontario osteoarthritis of the shoulder index (WOOS). 2,137 primary shoulder arthroplasties (70% women) were reported to the registry between January 2006 and December 2008. Mean age at surgery was 69 years (SD 12). The most common indications were a displaced proximal humeral fracture (54%) or osteoarthritis (30%). 61% were stemmed hemiarthroplasties, 28% resurfacing hemiarthroplasties, 8% reverse shoulder arthroplasties, and 3% total arthroplasties. Median WOOS was 59% (IQR: 37–82). 5% had been revised by the end of June 2010. The most frequent indications for revision were dislocation or glenoid attrition.

No abstract

Background and purposeThe 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 methodsThe 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.ResultsThe 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.ConclusionWe 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.

In this study, we evaluated patient-reported outcomes, the rate of revision and the indications for revision following resurfacing hemiarthroplasty of the shoulder in patients with osteoarthritis. All patients with osteoarthritis who underwent primary resurfacing hemiarthroplasty and reported to the Danish Shoulder Arthroplasty Registry (DSR), between January 2006 and December 2010 were included. There were 772 patients (837 arthroplasties) in the study. The Western Ontario Osteoarthritis of the Shoulder (WOOS) index was used to evaluate patient-reported outcome 12 months (10 to 14) post-operatively. The rates of revision were calculated from the revisions reported to the DSR up to December 2011 and by checking deaths with the Danish National Register of Persons. A complete questionnaire was returned by 688 patients (82.2%). The mean WOOS was 67 (0 to 100). A total of 63 hemiarthroplasties (7.5%) required revision; the cumulative five-year rate of revision was 9.9%. Patients aged < 55 years had a statistically significant inferior WOOS score, which exceeded the minimal clinically important difference, compared with older patients (mean difference 14.2 (8.8; 95% CI 19.6; p < 0.001), but with no increased risk of revision. There was no significant difference in the mean WOOS or the risk of revision between designs of resurfacing hemiarthroplasty.

No abstract

No abstract