Look into the knee like a keyhole surgeon!
See the internal ligaments and shock absorbers of the knee - the cruciate ligaments and menisci - and locate the boundaries of the capsule from the inside. This will help you to understand the later sections on the kinds of knee surgery for the stiff knee.
Transcript of video
In the previous lecture we talked about the capsule itself, and in this lecture we will explore the important structures inside the capsule.
During keyhole surgery operations of the knee - what we call 'arthroscopy' - the knee surgeon may fill the joint cavity with fluid under pressure to blow the capsule up so that he can see what he is doing inside.
Let's peer into the interior of the joint space towards the middle of the hinge area, and look at the image on a screen like a keyhole surgeon would. Note that his light and instruments are passed into the knee cavity behind the kneecap, so in this picture you are going to see is what is going on behind the kneecap.
You will readily appreciate the femur bone, which has two rounded ends with a deep notch between them. This notch contains two ligaments that are crossed over one another. The one ligament goes from the tibia at the bottom front to the femur at the top back and the other does the opposite. These are the cruciate ligaments, and the word 'cruciate' means 'crossed'. These two crossed-over ligaments facilitate the hinge movement, but also create a forwards-and-backwards restraint between the two bones. The notch is also important in our discussions about knee stiffness - anything locking up that notch or locking up the cruciate ligaments themselves is going to prevent these structures from functioning properly.
On the other bone of the hinge joint - the tibia - and on either side of the cruciate ligaments are two structures that act as shock absorbers - these are the menisci. They are important and complex but for the purposes of this section I just want to mention them and also to draw attention to the little ligament between them, which is called the intermeniscal ligament, and which helps to maintain the position of the two menisci in relation to one another.Down the outer side of the tibia are the capsular gutters that we have already mentioned in a previous lecture.
Down the front of the tibia is a deeper gutter, which is called the 'anterior interval'. This is an area that is particularly important when we get to talking about knee stiffness.
Snugging into the notch and anterior interval - although it doesn't arise there - is a structure called the 'fat pad' and it is easy to recognise from within the joint as it is bright yellow. The fat pad is a space-filling cushion that protects this area from knocks, but it can itself become traumatised and scarred, and then it can become problematic. It is attached to the capsule in the region below the kneecap, so it tends to be pulled out of the way of the instruments when the cavity is inflated during surgery. Sometimes, however, it is quite big and can obstruct the surgeon's view when he is exploring the notch structures.
So we have had an inside look at the anatomy deep to the kneecap, and in the next section we will take a look at the kneecap itself.
You might like to take a look at this YouTube Video as well [by Randy Clark]