Is That Shoulder Test Accurate?
By Warren Hammer, MS, DC, DABCO
We routinely evaluate shoulder problems such as rotator-cufftendinitis, cuff tears, labral tears (including SLAP lesions), instability, etc., with tests that often are considered valid since they are written up in orthopedic texts and journal articles. However, it is important to evaluate those tests as to their true validity. As I quoted in a previous Dynamic Chiropractic article,1 most orthopedic tests for the shoulder cannot truly isolate a particular structure, since when we use tests that compress or stretch an area, adjacent structures also have to be compressed, stretched or contracted.
Lewis2 feels that these tests are basically symptom or pain tests, especially since although they usually demonstrate a high sensitivity (proportion of actual positives that are correctly identified, i.e., the percentage of sick people who are correctly identified as having the condition), they have a low specificity (the proportion of negatives that are correctly identified, i.e., the percentage of healthy people who are correctly identified as not having the condition). In other words, we are unable to determine the patients who don't have the problem, which prevents us from determining the patients who have the problem.
My 2009 article was based on the findings of Hegedus, et al.,3 who had completed a meta-analysis of shoulder tests the year before. This article is based on Hegedus' findings of a follow-up meta-analysis of shoulder tests for 2012.4 In statistics, a meta-analysis refers to methods focused on contrasting and combining results from different studies in the hope of identifying patterns among study results, sources of disagreement among those results, or other interesting relationships that may come to light in the context of multiple studies.5
In Hegedus' meta-analysis, he makes us aware of the inherent bias in many studies, such as whether all of the patients were included in the analysis; failure to use a double-blind design; and that many tests with a high sensitivity and specificity have been studied only once (usually by the author of the test) and never confirmed by other scientists. Tests such as the active compression and biceps load II had excellent diagnostic statistics, only to have further research fail to replicate the results of the original authors.4
The question arises about testing for subacromial impingement (SIS) which if analyzed as a diagnosis, is a multifactorial shoulder problem that no single test can really evaluate. "Subacromial impingement syndrome (SIS) represents a spectrum of pathology ranging from subacromial bursitis to rotator cuff tendinopathy and full-thickness rotator cuff tears. The relationship between subacromial impingement and rotator cuff disease in the etiology of rotator cuff injury is a matter of debate."6
Both extrinsic compression and intrinsic degeneration may play a role, since a bursitis, cuff tear or tendinopathy can all be responsible for the so-called cluster of diagnostic possibilities called an SIS. One of the main tests for SIS is the Hawkins Kennedy, which apparently rules out SIS when it is negative; but this test, along with the Neer test and the painful arc test, has poor specificity and a negative likelihood ratio (-LR), indicating how much the odds of the disease decrease when a test is negative to rule out SIS.
Since there is no single pathognomonic shoulder test, the Hegedus meta-analysis revealed the best test combinations for various shoulder pathologies as follows:4
For more information regarding any of the tests mentioned in this article, just enter the test name in Google. Performance of these tests is often demonstrated on YouTube.
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