Table 1 Scheme of methods of present study
Research question | Statistical method | Outcome |
|---|---|---|
1) Is there association between joint fluid metal ion levels with histological observations? | Spearman rank correlation coefficient | Higher value of significant coefficient indicates higher association with metal ion levels and histological findings |
2) Do cobalt and chrome levels in joint offer good or excellent discriminative ability predicting histological findings? | Value and significance of AUC in ROC curve using Obuchowski method | AUC of >0.75 indicates good or excellent AUC. Sample size criterion must be met to produce significant AUC |
3) What is the sensitivity and specificity of optimal cut-off value for chrome and cobalt levels predicting histopathological findings? | Youden J -statistic | Produces optimal threshold (or cut-off) value defined as maximal distance from ROC curve to diagonal line |