According to Park et al., which combination of tests yields the best post-test probability for full-thickness rotator cuff tear?

• A. Painful arc sign, drop-arm sign, and infraspinatus muscle test
• B. Empty can test, external rotation lag sign, and Hornblower sign
• C. Painful arc sign, Hawkins-Kennedy test, and supraspinatus isolation test
• D. Drop-arm sign, abdominal crunch test, and biceps provocation test

Answer: (A)

Combining signs that reflect a large rotator cuff tear increases the likelihood of confirming the tear after testing. The painful arc sign points to subacromial pain during mid-range elevation, which is common with rotator cuff involvement. The drop-arm sign shows an inability to control the arm during lowering after abduction, a classic indicator of a full-thickness supraspinatus tear and related cuff pathology. The infraspinatus muscle test assesses external rotation strength; weakness here suggests infraspinatus involvement, reinforcing the suspicion of a significant tear when paired with the other signs. Taken together, these three findings provide a stronger post-test probability for a full-thickness rotator cuff tear than any single test alone, because they cover both tear presence and the functional impact on the cuff.

Other test sets may include signs that focus more on impingement or isolating a single muscle rather than indicating a full-thickness tear, or they combine with tests that assess unrelated structures (like the biceps or abdominal maneuvers). While those can be informative for broader shoulder pathology, they don’t yield as high a post-test probability for a full-thickness tear when used together.