In an article entitled “Bucket-Handle Meniscal Tears of the Knee: Sensitivity and Specificity of MRI signs,” Dorsay and Helms (A-6) performed a retrospective study of 71 knees scanned by MRI. One of the indicators they examined was the absence of the “bow-tie sign” in the MRI as evidence of a bucket-handle or “bucket-handle type” tear of the meniscus. In the study, surgery confirmed that 43 of the 71 cases were bucket-handle tears. The cases may be cross-classified by

“bow-tie sign” status and surgical results as follows:

(a) What is the sensitivity of testing to see if the absent bow-tie sign indicates a meniscal tear?

(b) What is the specificity of testing to see if the absent bow-tie sign indicates a meniscal tear?

(c) What additional information would you need to determine the predictive value of the test?

Transcribed Image Text:

Positive Test (absent bow-tie sign) (T) Negative Test (bow-tie sign present) (T) Total Tear Surgically Confirmed (D) 38 5 Tear Surgically Confirmed As Not Present (D) 10 18 Total 48 48 23 25 43 28 71