ARE SPECIAL TESTS A NECESSITY FOR DIAGNOSIS?

ARE SPECIAL TESTS A NECESSITY FOR DIAGNOSIS?

Trust me-Ed

Most clinicians approach assessment by starting with history, then observations, palpation, orthopaedic tests, and then formulate a working diagnosis. In some instances they think about a scan to confirm it and then manage the pathology accordingly. Physical therapists often use clinical special tests at the beginning of an examination to ‘rule out’ a condition, or near the end of the examination to ‘rule in’ a finding.²

 

If you want to learn more about this topic, you can watch Ian Gatt's lecture here:

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Terminology such as sensitivity, specificity, and positive and negative likelihood ratios help provide value to a test, help decide when a test should be used, and assist in discriminating which tests actually help during decision making, or add nothing to the final determination. Sensitivity refers to the percentage of people who test positive for a specific disease among a group of people who have the disease. Specificity refers to the percentage of people who test negative for a specific disease among a group of people who do not have the disease. Positive and negative likelihood ratios are calculated using both sensitivity and specificity, and are values that influence the post-test probability of decision making.²

 

 

If we look in the literature, one of the things that’ll tell us is that one test won’t give us the diagnosis. There’s no one test which has 100% specificity and sensitivity. Either It includes a pathology or excludes the pathology. Some recent studies say that it is not worth doing these tests if they don’t give us the best diagnosis. One of the things to reflect upon is that, these special tests are like stress tests, so whether you use tests for the hands and wrists, or the elbows or for the shoulders; they are  providing potentially added value or added quality. Rather than thinking, I have done this test and it is definitely the structure, what we can comment is, I have done this test and it provides this particular reaction, this amount of pain or clicking or that feeling of instability.

Another point to remember is that, we should do these tests before we do other tests because the moment we start touching or palpating, we change things. It can cause structures to be more painful and therefore obviously it will negatively bias the other tests and objective markers.

So when you start putting your hands on it, you really have to think about what is going to happen.

For example, you could be doing the Scaphoid Shift Test; also known as the Watson’s test which can be a nice test because rather than having to palpate dorsally, where usually they have the pain, you’re actually palpating palmarly, which provokes the pain dorsally. So it can be useful in the diagnostic element.

If we consider the shoulder, according to books and references a specific position seems to be everything while doing a test. But we should also remember that the cuff is active in all positions. So just because you do a test and it is negative doesn’t mean that it is okay. Because it could be that they’re not painful in that direction but they might be painful 20 to 30 degrees in a different direction. So it’s not about the test trying to fit the pathology. What we have to ask is, does the test we do facilitate what we are trying to achieve? Is it adding any qualitative prognostic value?

 

  

 

If you want to learn more about this topic, you can watch Ian Gatt's lecture here:

Click here

 

Sources:

1. ‘The sporting upper limb’ by Ian Gatt.

2. Chad Cook; The lost art of the clinical examination: an overemphasis on clinical special tests; 2010 ; Journal of Manual and manipulative therapy.

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