What is the Anterior Drawer Test?
The anterior drawer test (ADT) is a simple but effective way to determine if your anterior cruciate ligament (ACL) has been torn or not. You may have heard about it before, but there are many different ways to perform the ADT. The most common method involves placing one hand into a small opening in your shoe and another hand inside the shoe with the fingers extended outwards towards your knee joint. If the two hands touch when you extend your arms straight out, then your ACL is healthy.
In order to perform the ADT correctly, you need to know what part of your foot touches the floor first. There are several methods to do this, but here’s how I’ve done it:
I place my left foot on top of my right foot so that my big toe rests against my heel. Then I put my other hand behind my back and bend over until my knees are bent. My body remains still while I pull up on the outside of my right knee with both hands. With all the weight resting on the inside of my right knee, I slowly lower myself down toward the ground until only a few inches remain above the floor. At this point, I lift up off of the floor and repeat with my left leg.
Whichever foot that comes into contact with the floor first is the foot that touches the ground first when you walk. For example, I usually come into contact with the outside part of my heel and the inside part of my toe when I walk. This method is very accurate for me, but you may need to use a different method in order to identify which part of your foot touches the floor first.
When the Anterior Drawer Test is Positive
If you perform the test and your knee slides outwards (draws a letter “C”) as you extend your leg, it’s a positive test and you have an ACL injury. This is especially important if you feel pain while performing the test. If this is the case, see a doctor immediately. A torn ACL can lead to long-term problems with arthritis in that knee, which could require a knee replacement in the future.
When the Anterior Drawer Test is Negative
If you perform the test and your knee doesn’t slide outwards when you extend your leg, then the result is negative. This means that your ACL is healthy. However, this does not mean that you don’t have a torn meniscus or another type of knee injury. If you have knee pain, then see a doctor immediately and get an MRI to check for other types of injuries.
The Lachman’s Test
The Lachman’s test is similar to the Anterior Drawer Test, except that you pull your knee forward instead of extending your leg straight out. This test is typically used on patients who can’t fully extend their knee because of pain or other medical conditions.
To perform the test, place your foot parallel to the ground. Then bend your knee and push your hips forward. A physical therapist or doctor will hold your heel to prevent you from moving backward while they check your range of motion. Next, grab onto your knee and pull it forward while you try to keep your hips still. Don’t force your knee forward if you feel any pain or discomfort.
In this case, the physical therapist or doctor is looking for a gap between your tibia and femur. The wider the gap, the more severe your injury is.
How to Know if the Test is Positive or Negative
A positive test is when you can easily slide your hand or the doctor’s hand more than 10mm past your knee cap. A negative test is when you can’t slide your hand past your knee cap more than 10mm.
Your tibia (shin bone) should touch your femur (thigh bone) in some part of its range of motion. If a large gap appears during this test, it might be a sign of a severe injury. The Lachman’s test can also help to detect instability in your knee and whether you need surgery or not. If the test is negative but you’re experiencing any pain or have trouble bearing weight on that leg, then you should get an MRI to look for other types of damage.
Sources & references used in this article:
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Ligament fibre recruitment and forces for the anterior drawer test at the human ankle joint by F Corazza, JJ O’connor, A Leardini, VP Castelli – Journal of biomechanics, 2003 – Elsevier
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