Hi, I'm Chris Fulmer. I'm one of the faculty members for the Stanford O'Connor Sports Medicine Fellowship. For this video, I'm going to focus on a patient presentation in which the patient reports a non-contact injury and either feeling or hearing a pop. When you get a history like this, certainly you should be most suspicious for some sort of anatomic disruption, particularly in a non-contact situation, a meniscal tear, a ligamentous rupture or sprain, or a patellar subluxation or dislocation. As you go through your evaluation, especially if you're finding that multiple ligaments may be injured, you should have a higher suspicion for a knee dislocation and thus checking the neurovascular status of the patient early on in your exam is incredibly important. When you have a hyperextension injury or if you have localization of the patient's pain or tenderness to the lateral side of the knee, those would call to mind more likely injury to the lateral collateral ligament, the PCL, or the posterior lateral corner. So moving forward, I'm going to focus on examinations to look at those structures. So the first thing you want to do is certainly test range of motion, look for a knee effusion with any significant ligamentous injury or other anatomic disruption, you would be most likely finding a knee effusion. The first test I'll demonstrate is the Varus stress test. The important thing here is you want to make sure the patient is comfortable and relaxed. So I will usually start my exam with the knee in approximately 30 degrees of flexion and pressing using the hand on the inner side of the knee, exerting a force that comes laterally is the Varus stress test. So I'm stressing the lateral collateral ligament. You want to do this in both 30 degrees of flexion and in zero degrees of flexion or full extension. From here, I'll look for what's called the sag sign. So placing the patient's hip into some flexion and knee inflection, you want to look at this anterior contour of the knee and see if there's any visible sag of the anterior tibial surface. If you're having a hard time distinguishing, you can certainly bring the other, the patient's contralateral knee into a similar position and evaluate. If there's any posteriorly directed sag of the tibia, that would be suspicious for a PCL injury. Next, I'll be demonstrating the active quadricep test. This is another test for the PCL. Similar position as the sag test, you're going to palpate anteriorly over the tibia and have the patient actively use their quadriceps. To do this, I'm sitting on the patient's toes to immobilize the foot and I'm going to have them attempt to push their foot or slide their foot forward on the table as they do this and relax. As they do that, if you feel the tibia move anteriorly out of that sagging position, this would be consistent with a PCL injury. Alternatively, for an ACL injury, you can have them do just the opposite, same position, but have them try to draw their heel backwards and relax. And if you feel the tibia translocate, that would be suggestive of an ACL injury. I'm going to now demonstrate the frog leg test. So you have the patient assume this position with the legs out to the side. This is a test, it's been described as a test either for the posterior lateral corner or for the lateral collateral ligament. I would say that the data is more suggestive that it's more accurate for testing the lateral collateral ligament. To perform this test, once they're in this position, you place your hands over the proximal tibia and you push posteriorly. You can just globally assess whether there's pain or laxity with that. You can also use one hand as a monitoring hand over the lateral joint line, and use your other hand to exert that lateral force and see if there's movement. The last test I'll demonstrate is the dial test. This test is used to detect either posterior lateral corner injuries or PCL injuries. To do this test, you have the patient get into the prone position. You bring their knees as close together as possible. You flex their knees to 30 degrees and externally rotate the tibia. What you're looking for here is a difference in external rotation from one leg to the other, or in the case of an injury, the injured leg to the other. If there's more than a 10 degree difference, that would be a positive test. After you perform the test in 30 degrees, you bring them up into 90 degrees and repeat that same maneuver, bringing them into maximal external rotation. Again, what you're looking for is greater than 10 degrees difference. To evaluate your findings of the dial test, you will be looking at where you saw that difference in external rotation. If that external rotation was present at 30 degrees but not at 90 degrees, that is more consistent with a posterior lateral corner injury. If the difference is at 90 degrees and not at 30 degrees, that's more consistent with a PCL injury. Finally, if you find that difference at both 30 and 90 degrees, that would be indicative of injury to both structures, which is a much more significant injury.

2nd Edition, CASE 28

2nd Edition

Knee

knee injuries

meniscal tears

ligament ruptures

diagnostic tests

neurovascular status