How we diagnose ACL tears

It’s always important to be aware of new trends in Anterior Cruciate Ligament detection, so a recent study conducted by Houston Methodist Hospital caught my eye. The study, conducted over the course of a year which involved 91 patients aged 16 to 60 who had experienced a knee injury with subjective swelling or an objective effusion – and they were all examined for ACL tears by a method called the lever test.

What is the lever test?

Otherwise known as the Lelli’s Test, after the person who devised it, the lever test involves getting the patient in a prone position and then placing a fist a third of the way down the underside of the calf, whilst applying moderate downward pressure on the distal third of the quads, whilst the heel of the leg remains in contact with the surface. If the patient’s foot rises while pressure is being applied, it is to be assumed that there is no ACL tear. If the heel remains resting on the table and the foot doesn’t rise, there is a distinct possibility of a partial or full ACL tear. A video demonstration of this can be found below.

As you may have already deduced, this method is a little less high tech than other ACL tests, but the results showed that 78% of patients had MRI-confirmed complete ACL tears. Moreover, the study found that the lever test had a sensitivity of 83%, a specificity of 80% and an accuracy of 82% – which was statistically similar to results from other, more established tests, such as the Lachman, anterior drawer and pivot shift tests.

A challenge to the Lachman test?

The study points out that, like the Lachman test, which has been the industry standard in hands-on ACL tear detection, the presence of a meniscus tear leads to a decrease in the accuracy of the lever test, which doesn’t affect the accuracy of the pivot shift test. But the simplicity of the lever test, the painless nature of the procedure and the fact that no grading is involved (in other words, either the heel lifts off the surface, or it doesn’t) makes it a perfect exploratory method for practitioners who don’t specialise in ACL examinations. It’s certainly easier to perform than the Lachman test.

The presence of a complete, chronic tear of the ACL is possible to detect with all manual tests but diagnosing a partial tear can be more challenging. All tests are important to help make a clinical diagnosis for patients.