Hertel, J Shoulder Elbow Surg 1996 - Lag Signs in the Diagnosis of Rotator Cuff Rupture - Article Summary

Lag Signs in the Diagnosis of Rotator Cuff Rupture

Hertel, Gerber, et al.·J Shoulder Elbow Surg·1996·427 citations·Prospective cohort

Hertel and colleagues tested how well three lag signs detect rotator cuff tears compared with the Jobe and lift‑off signs.

Prospective study of 100 consecutive painful shoulders, impingement stages 1 to 3, at the University of Berne.

Methods

Design: Prospective study
Patients: 100 consecutive painful shoulders
Impingement syndrome stages 1 to 3
Shoulders with any loss of passive motion excluded
Index test: External rotation lag sign (ERLS)
Drop sign
Internal rotation lag sign (IRLS)
Jobe and lift‑off signs tested as comparators
Reference standard: Cuff findings at open or arthroscopic exploration
Outcomes: Sensitivity and specificity
Positive and negative predictive values
Lag magnitude vs tear size

Key Findings

For supraspinatus and infraspinatus tears, the ERLS was less sensitive than the Jobe sign but significantly more specific (p = 0.002).
The drop sign had the lowest sensitivity of the tests but matched the ERLS for specificity.
For the subscapularis, the IRLS was more sensitive than the lift‑off sign with equal specificity, and it detected 4 of 5 partial tears that the lift‑off sign missed entirely.
ERLS lag tracked tear size: 5° to 10° in 16 of 17 isolated supraspinatus tears and 10° to 15° in all 11 complete tears of both supraspinatus and infraspinatus.
Nerve deficits can give false‑positive lag signs: in 4 patients outside this series with complete suprascapular nerve palsy, the ERLS and drop sign were all positive.
Lag signs need full passive motion, because capsular contracture masks a lag and excess external rotation from a subscapularis tear can cause a false‑positive ERLS.

Board pearl

The ERLS misses partial‑thickness supraspinatus tears: only 1 of 19 showed any lag, and that lag was 5°.

Lag signs rarely gave false positivesHertel, J Shoulder Elbow Surg 1996

Lag signs rarely gave false positives
Jobe sign (63 posterosuperior tears, 24 intact cuffs)	84% 53 of 63	58% 14 of 24
ER lag sign (63 posterosuperior tears, 24 intact cuffs)	70% 44 of 63	100% 24 of 24
Drop sign (63 posterosuperior tears, 24 intact cuffs)	21% 13 of 63	100% 24 of 24
Lift-off sign (29 subscapularis tears, 24 intact cuffs)	62% 18 of 29	100% 24 of 24
IR lag sign (29 subscapularis tears, 24 intact cuffs)	97% 28 of 29	96% 23 of 24

Authors' conclusion

The authors conclude that the external and internal rotation lag signs and, to a lesser degree, the drop sign, were helpful in the clinical evaluation of rotator cuff rupture and were superior to the Jobe and lift-off signs. Partial ruptures of the supraspinatus may remain concealed to the external rotation lag sign, whereas partial ruptures of the subscapularis may be confidently diagnosed by the internal rotation lag sign.

Core

Lag Signs in the Diagnosis of Rotator Cuff Rupture.

Hertel, Gerber, et al.J Shoulder Elbow Surg1996427 citationsProspective cohort