Internal Rotation Lag Sign

Original Editor - Ron Bucholtz

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Purpose

To test for rotator cuff tears of the Subscapularis tendon

Technique

Patient is seated with examiner behind patient.  The affected arm is brought into maximal internal rotation behind the back (dorsum of patients hand against the lumbar region).  Examiner controls patient's arm at the elbow and wrist/hand which is passively brought into 20 degrees of extension taking the forearm and hand away from the back.  Instruct patient to actively maintain this position as examiner releaes the wrist but maintains support at the elbow.  A lag is indicative of a subscapularis tendon tear.,5  Hertel, et. al. describe the magnitude of the lag in 5 degree intervals with an obvios drop indicating large or massive tear and a smaller lag revealing a partial tear.

Please note that the Internal Rotation Lag Sign (IRLS) is also described by Magee⁵ as the "subscaplaris or medial rotation 'srping back' or lag test" in addtion to the "modified lift-off test".

Evidence

Hertel, et. al. (also cited in Cleland report Sensitivity (Sn) .97, Specificity (Sp) .96, positive Liklihood ratio (LR+) 24.3, and negative Liklihood Ratio (LR-) of .03 for the IRLS.

A more recent study by Miller, et. al. report Sn 1.0, Sp .84, LR+ 6.2, LR- 0.0 with Positive Predictive Value (PPV) 28% and Negative Predictive Value (NPV) of 100 for the IRLS.  These values are compared to diagnostic ultrasound wihch has been found to be comparable with arthroscpy for diagnosing RTC tears.  However, they summize that clinical diagnosis of full thickness tears of the rotator cuff cannot be conclusively reached using one or more of the lag signs . The other lag sings investigated in theis study are the drop sign and external rotation lag sign (ERLS).

Recent Related Research (from Pubmed)

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References

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1.  Hertel R, Balmer FT, Lombert SM, Gerber C.  Lag signs in the diagnosis of rotator cuff rupture.  J Shoulder Elbow Surg.  1996 Jul-Aug:5(4):307-313                                                                                                                                         

2.  Miller CA, Forrester GA, Lewis JS.  The validity of the lag signs in diagnosing full-thickness tears of the rotator cuff:  a preliminary investigation.  Arch Phys Med Rehabil.  2008 Jun:89(6):1162-8                                                                    

3.  Magosch SM, Pritsch M, Lichtenberg S, Habemeyer P.  The belly-off sign:  a new clinical diagnostic sign for subscapularis lesions.  Arthroscopy: 2005 Oct:21(10):1229-35                                                                                     

4.  Cleland J.  Orthopaedic Clincial Examination:  An Evidence Based Approach for Physical Therapists:  Philadelphia:  Saunders - Elsevier.  2007                                                                                                                                         

5.  Magee, DJ.  Orthopedic Physical Assessment:  St. Louis:  Saunders - Elsevier:  (4th Ed.)  2006.

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