Which history and physical findings are most useful in identifying rotator cuff tears?
The combination of the painful arc sign, drop-arm sign, and weakness in external rotation (positive infraspinatus muscle strength test) produced the best likelihood ratios (LRs) for detecting full-thickness rotator cuff tears ( TABLE ).
TABLE
Comparison of tests to detect full-thickness rotator cuff tear
| Test | Sensitivity | Specificity | LR+ | LR- |
|---|---|---|---|---|
| Painful arc2 | 75.8%* | 61.8%* | 15.57† | 0.16† |
| Drop-arm2 | 34.9%* | 87.5%* | ||
| Infraspinatus muscle strength2 | 50.5%* | 84%* | ||
| Supraspinatus muscle strength3 | 88% (95% CI, 0.79-0.97) | 70% (95% CI, 0.58-0.82) | 2.93 | 0.17 |
| CI, confidence interval; LR, likelihood ratio. | ||||
| *Confidence intervals not reported. | ||||
| †LR when all 3 tests are combined. | ||||
A winning diagnostic combination for any degree of impingement disease
The best combination of tests to diagnose any degree of impingement disease is:2
- a positive Hawkins-Kennedy impingement sign
- a positive painful arc sign
- a positive infraspinatus muscle strength test.
Negative supraspinatus test helps rule out massive tear
A third study evaluated the validity of the supraspinatus muscle strength test alone to diagnose patients with rotator cuff pathology using arthroscopy or open surgery as the reference standard.3 A negative supraspinatus test, when defined by weakness, significantly decreased the posttest probability (LR-=0.17) of detecting a massive rotator cuff tear.
Correlate test results with clinical history
Most individual tests for rotator cuff disease are not sensitive or specific enough to effectively rule in or rule out a rotator cuff tear. Many of the findings studied can be positive in the presence of other shoulder conditions and should be correlated with the clinical history of each patient. One of the noted limitations of these 3 studies is that none was carried out in a primary care setting.
