The Journal of arthroplasty
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The statistical analysis of a study's results is critical to its interpretation. Often confused, 2 types of t tests exist for dependent or independent samples. We reviewed randomized controlled trials that included patients undergoing bilateral total hip or knee arthroplasty (dependent samples) that used the t test for analysis. ⋯ Of the 30 studies that compared a pure sample of only bilateral patients, 18 (60%) incorrectly used the independent t test. Of the 10 studies with mixed samples, 8 (80%) used the independent t test. The extent to which the incorrect use of this statistical test led to misleading conclusions is uncertain; however, our findings highlight the misuse of statistical tests in the arthroplasty literature.
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The purposes of this study were to evaluate the accuracy and reliability of preoperative templating on conventional radiographs (CRs) for metal-on-metal hip resurfacing and to determine the factors affecting the accuracy. Four observers templated 80 CRs on 2 separate occasions in a blinded fashion. Eight independent variables were evaluated to investigate their effect on the accuracy of templating. ⋯ Overall, the intraobserver and interobserver reliability was fair to substantial (κ = 0.22-0.61). Using multiple regression analysis, surgical time was the only factor that affected the accuracy of predicting the size of the acetabular component (P = .019). We conclude that CR templating for metal-on-metal hip resurfacing is a useful method for preoperative planning of the sizes of the respective implants and that surgeon experience does play a significant role in the accuracy of predicting component size during templating.
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This follow-up study reports on 69 patients at mean 13 years with total hip arthroplasty using 28-mm Metasul (Zimmer, Winterthur, Switzerland) metal-on-metal articulation. These results are not transferable to large-diameter head metal-on-metal articulations. ⋯ No revision was done for osteolysis. Overall, of the original 127 hips, 116 (91%) were known to have maintained their original components.
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The purpose of this study was to evaluate and compare the quality of life and satisfaction outcomes of patients undergoing primary and revision total knee arthroplasty (TKA). Sixty revision and 199 primary TKA patients were assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Oxford-12 Knee Score, Short Form-12, and patient-reported satisfaction. ⋯ At follow-up revision, TKA patients continue to have inferior outcomes (P < .05) in comparison with primary TKA patients. When adjusting for confounding factors in regression analyses, revisions are inferior to primary TKA by 8.6 (95% confidence interval, 2.7-14.6) normalized WOMAC units.