Wednesday, July 18, 2007

I have recently begun using a nice new clinical test for meniscus tears. It is called the Thessaly Test (I thought we were going to quit naming things like this after ourselves, lol). It is a weight bearing test, so it's fairly functional. The Abstract can be found on the Journal of Bone and Joint surgery. The test basically requires the practitioner to hold the hands of the patient who is standing on one leg. The patient then bends to 5° and twists medially then laterally. The test is repeated at 20°. Positive test equates to reproduction of pain, catching or popping.

Here is a summary from EBM Online:

Diagnostic characteristics of the Thessaly test at 20° of knee flexion for identifying meniscal tears*
Diagnosis Sensitivity (95% CI) Specificity (CI) Accuracy +LR –LR

Medial meniscal tear 89% (83 to 94) 97% (94 to 98) 94% 26.9 0.11
Lateral meniscal tear 92% (78 to 98) 96% (93 to 98) 96% 22.9 0.08

*Diagnostic terms defined in glossary; CI and LRs calculated from data in article.

In my experience, the test is easy to administer and less physical work needed by the practitioner compared to McMurray's or Apley Grind. However, like McMurray's or Apley, in the clinic, they don't quit appear as strong individually as they do when grouped.


Jason L. Harris, PT, DPT said...

A Comment on the statistics, which appear very strong.

1. Often, a test that has high specificity (ie if positive rules the condition in) does so at the expense of sensitivity (ie if negative rules the condition out). This has both high specificity and sensitivity. Meaning, if positive they likely have a meniscal tear and if negative it's very likely the don't have a meniscal tear.

2. Likelihood rations (+ and -): These are a function of the specificity of the specificity and sensitivity. For Positive Likelihood ratios (+LR) anything over 10 is a "Large and often conclusive increase in the likelihood of disease" or condition. This test ranges from 22.9 for the lat meniscus and 26.9 for the med meniscus. That is a very large shift in positive likelihood. For the negative likelihood ratio, anything less than 0.1 is "Large and often conclusive decrease in the likelihood of disease".

Here is a good link that discusses + and - likelihood ratios is you want a greater explanation:

Point is, this paper demonstrates a very significant statistically important test to rule in and even rule out meniscus tears. Add it to your diagnostic toolkit.

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