Aaron Jones Injury, Left Knee Bends Awkwardly

Aaron Jones of the Green Bay Packers was carted to the locker room during Sunday's game against the Chargers.

Welcome back, my name is Dr. Stefan Wilson and the purpose of this channel is to learn more about sports injuries.

We'll go right to the replay here. Here we see Aaron Jones is the ball carrier where he runs into the interior of the Chargers defensive line where 3 defenders engage him. First, I want us to look at the defender who is on the ground. You can see how he has ahold of Jones's right foot and his foot is up off of the ground. That means in this moment, Jones's only base of support touching the ground is his left foot and leg. Two more defenders are then working together to bring Jones down to the ground but in doing so, we can see how his left leg and knee are being bent in a very awkward position. His left foot is pointing outwards slightly and is being externally rotated. That means his lower leg and his tibia and fibula are slightly pointing outwards as well. All the while the downward compressive force of the two defenders causes his left knee to buckle sort of speak with his left knee being forced to the inside. Whenever this happens, we call this a valgus force on his knee that forces the hinge joint of the knee to bend sideways into a fairly unnatural position. This downward pressure continues for a few moments before Jones is pushed backwards and is brought down to the ground. Here Jones's leg, hip and back muscles would all be firing at once in order to maintain stability, but the his left knee ligaments would also be under considerable pressure.

On the anatomy model here we can see the picture of the knee joint. To orient ourselves we see the thigh bone on top which is called the femur and the shin bone below called the tibia. In between those bones we have the joint space of your actual knee. Your femur and tibia are held together by a group of ligaments that connect your femur and tibia together that provide stability. Now remember that stability works the best when the knee is moving back and forth like a hinge. But when we apply a force from the outside, with your tibia in external rotation that is going to place stress to your medial collateral ligament and your anterior cruciate ligament, especially when your knee is bending into flexion. Also located between your femur and tibia is of course your meniscus which is a smooth section of cartilage.

When we look back at the replay again, we can see Jones's plant leg, his left leg, which is under a lot of compression because he has two defenders bringing him down, his left knee is being forced to the inside while his left foot remains stationary. This valgus stress on his knee is going to compromise the ligaments in his knee, most likely his MCL his ACL and possibly his medial meniscus as well. Aaron Jones will certainly undergo an MRI in order to determine the exact extent of injury to his left knee. Hopefully for Jones this is not a season ending injury.