Hi, I'm Chris Fulmer. I'm one of the faculty members for the Stanford O'Connor Sports Medicine Fellowship. In this case, we have a patient who presents with knee pain and an effusion. There are several things that can cause an effusion, but for the sake of this video, I'm going to focus on testing for meniscal pathology. One key point to start with is that of all the tests we have for meniscus, none of them have very good sensitivity or specificity. So, it's important to cobble together all of the pieces of data from your encounter with the patient, including their mechanism of injury, their symptoms and signs, and your physical exam to help you discern the likelihood of a meniscal pathology. So, starting with the patient's presentation, certain symptoms are fairly classic for a meniscus tear or injury. Those would include recurrent effusion, popping, clicking, or locking of the knee. As far as mechanism of injury goes, the classic description is that of a twisting or a torquing of the knee while the foot is planted on the ground. Moving to the physical exam, I usually start with palpation of the joint line to assess for joint line tenderness. If the patient has an effusion at the time of your evaluation, you may be very limited in how much knee flexion you can induce, so start with whatever the patient can tolerate. I'll start with palpating the medial joint line because it is the easiest to differentiate on your physical exam. I'll identify the medial border of the patellar tendon and find that beginning of the joint line anteriorly, and I'll palpate along its entire course to the posterior-most aspect. For sake of demonstration, I'm going to use the patient's other knee here. So, when you're palpating the lateral joint line, it's a little more difficult to palpate in this position, but again, find that lateral border of the patellar tendon, find the joint line, and palpate again across its entire length until you get to the posterior-most aspect of the joint. If you're having difficulty finding that lateral joint space, one trick that you can do is you can bring the patient into a figure-of-four position and allow their leg to come out to the side, and that will cause gapping of the lateral joint line. Once you've palpated both the medial and lateral joint line, you can begin performing some of the special tests. Again, assuming that the patient is presenting with an effusion, what I'll usually start with is the knee in its position of comfort, which is going to be near full extension. So, I'll start with the bounce test. It's very important that you get the patient to fully relax. A lot of times what I'll end up doing is kind of taking the knee into partial flexion and extension until the patient relaxes their hamstrings and their quadriceps, and then from there, in just a few degrees of flexion, then I'll drop the knee into full extension. This is the bounce home test or the bounce test. In some texts, it's also referred to as the lock home test. If the patient experiences pain with that, it's not very specific, but one of the things that could cause pain would be a meniscus tear. The most classic physical exam test that's described for meniscal pathology is the McMurray's test. Again, if the patient has significant knee effusion, it may be difficult to adequately perform this test. Ideally, you would place the knee into near full flexion, monitor both the medial and lateral joint lines with one hand, and with the other hand, you're going to induce some internal and external rotation of the tibia. To further increase the sensitivity of the test, I'll usually begin with fully flexing the knee and circumducting the tibia to increase the chances that we'll capture a loose torn flap of the meniscus. From here, you can alternatively externally rotate the tibia and extend the knee or internally rotate the tibia and extend the knee. Other tests that can be performed to assess the meniscus would include the Apley test. One of the most common times I'll use this test is if I'm really having a hard time distinguishing a collateral ligament injury from a meniscal injury. To perform the Apley's test, there are two components. There's the compressive element and the distraction element. For the compressive test, you bring the knee into 90 degrees of flexion. You brace the thigh with one hand and load the tibia with your other by inserting a compressive force. Once you've put that compressive force in, you rotate the tibia back and forth and assess the patient for any report of pain. The second part of the test is the distraction component. Again, holding the thigh stable, you're going to distract through the tibia and again rotate the tibia back and forth and assess for pain. If the patient experiences pain with compression but not distraction, that would be more indicative of a meniscal injury. If they have pain both with compression and distraction, many times that is more consistent with a collateral ligament injury. So now I'll ask the patient to perform the Thessaly test. Thank you. So again, we see here the patient is going into partial knee flexion. Their weight is compressing the knee joint and they're torquing back and forth. If they have pain with that movement, then that would be a positive Thessaly test.

2nd Edition, CASE 27

2nd Edition

Knee

meniscal pathology

knee pain

diagnostic tests

Chris Fulmer

Stanford Sports Medicine