Which Shoulder Special Tests Are Accurate?

SpECIAL TESTS

 

Many health care practitioners rely on orthopaedic special tests to evaluate specific pathologies within the shoulder. Unfortunately, many of these tests have proven to be unreliable and misleading. For example, the empty can test to evaluate a rotator cuff tear (mainly the supraspinatus muscle) is a common special test that is used widely in clinical practice and is still being taught in school. However, recent evidence has shown limited diagnostic value for this test, with a poor ability to differentiate structural lesions of the rotator cuff. In layman’s terms, many shoulder tests will provoke symptoms (high sensitivity) but cannot differentiate the cause of the symptoms (poor specificity).

If these common tests can’t be trusted, then which ones can?

Current evidence has shown the diagnostic utility of only a handful of orthopaedic special tests for shoulder pathology. This post will highlight the most useful tests and provide statistical values to back up those claims.

To understand what makes a special test useful, we must look at four statistical variables:

  1. Sensitivity
  2. Specificity
  3. Positive Likelihood Ratio
  4. Negative Likelihood Ratio

Sensitivity is the ability of a test to correctly identify those with the pathology. Specificity is the ability of a test to correctly identify those without the pathology.

In isolation, these values may not be as useful to the practicing clinician. This is where likelihood ratios are helpful. Likelihood ratios take both the sensitivity and specificity values and produce a number that gives a better diagnostic probability of a certain pathology.

LRcalc

A positive likelihood ratio tells us how much we should increase the probability of a particular pathology based on a positive test result. A negative likelihood ratio tells us how much we should decrease our suspicion of a particular pathology based on a negative test result.

LR table

In medicine, a positive likelihood ratio (LR+) of >5 is used to rule in a certain condition. Similarly, a negative likelihood ratio (LR-) of <0.2 is used to rule out a certain condition. Therefore, we can use LR+ to diagnose a condition and LR- to screen for a condition.

simplifying likelihood ratios

A study simplifying likelihood ratios outlined a method to estimate the percentage change in probability of a condition based on the likelihood ratio.

The following tests have proven to be valid in identifying specific shoulder pathologies. Click on the name or picture to read about the research behind each test.

Anterior Instability

Anterior Apprehension Test

anterior apprehension test

Sensitivity: 72      Specificity: 96      LR+: 18     LR-: 0.29      Use: Diagnose

 

Relocation

relocationtest

Sensitivity: 81      Specificity: 92      LR+: 10.1     LR-: 0.1      Use: Diagnose / Screen

 

Surprise

release test

Sensitivity: 92      Specificity: 89      LR+: 8.4     LR-: 0.08      Use: Diagnose / Screen

 

Labral Lesions

Passive Distraction

passive distraction test

Sensitivity: 53      Specificity: 94      LR+: 8.3     LR-: 0.5      Use: Diagnose

 

Passive Compression

passive compression

Sensitivity: 82      Specificity: 86      LR+: 5.7     LR-: 0.2      Use: Diagnose / Screen

special tests.

Modified Dynamic Labral Shear

modified dynamic shear test

Sensitivity: 72      Specificity: 98      LR+: 36     LR-: 0.29      Use: Diagnose

 

Subscapularis Tendinopathy

Belly-Off

belly off

Sensitivity: 86      Specificity: 91      LR+: 9.7     LR-: 0.14      Use: Diagnose / Screen

 

Belly Press

belly press

Sensitivity: 40      Specificity: 98      LR+: 20     LR-: 0.61      Use: Diagnose

 

Modified Belly Press

modified belly press

Sensitivity: 80      Specificity: 88      LR+: 6.7     LR-: 0.23      Use: Diagnose / Screen

 

Bear Hug

bear hug

Sensitivity: 60      Specificity: 92      LR+: 7.23     LR-: 0.43      Use: Diagnose

 

Rotator Cuff Tear (RTC)

Lateral Jobe

lateral jobe test

Sensitivity: 81      Specificity: 89      LR+: 7.4     LR-: 0.21     Use: Diagnose / Screen

 

External Rotation Lag Sign (ERLS)

ERLS

Sensitivity: 46      Specificity: 49      LR+: 7.2     LR-: 1.1     Use: Diagnose

 

AC Joint Pathology

AC Resisted Extension

acresistedext

Sensitivity: 72      Specificity: 85      LR+: 4.8     LR-: 0.3     Use: Diagnose

 

Bone Pathology

Bony Apprehension

bony apprehension

Sensitivity: 94      Specificity: 84      LR+: 5.9     LR-: 0.07     Use: Diagnose / Screen

 

Olecranon-Manubrium Percussion Test (OMPT)

OMPT

Sensitivity: 84      Specificity: 99      LR+: 84     LR-: 0.16     Use: Diagnose

 

Future of Special Tests

Not every shoulder special test was included in this article. If you are curious how some of the more common shoulder tests hold up to scientific scrutiny, check out this systematic review.

We don’t know the accuracy of clustering these special tests, perhaps because no study has been done to date. However, a recent study attempted to use the best available clustered tests and clinical prediction rules to inform clinical practice. They concluded that no one clinical tests is definitive for diagnosing shoulder pathology.

One other point that should be mentioned is the relationship between shoulder pathology on imaging and presence of symptoms. Many people are walking around with asymptomatic rotator cuff tears and studies have shown that athletes can compete painfree with evidence of labral tears. These factors are likely what prevent any orthopaedic special test from being 100% accurate. As always, no test should be interpreted in isolation to a thorough subjective and objective examination.

 

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