Like a hinge, the knee permits movement. But one fundamental element is missing. Unlike a hinge, the knee has no pin to connect the leg bones.
It depends on an intricate system of interior and exterior bands, special surfaces, and natural shock absorbers to facilitate and smooth the action, to say nothing of keeping the lower leg attached to its upper counterpart. That the knee is more than mechanical parts is best demonstrated by the fact that medical device manufacturers have not been able to devise an artificial replacement that truly reproduces the knee’s capabilities.
Four ligaments hold the four bones of the leg and knee together. These are dense bands of tissue. Cartilage appears in the knee in two forms: covering the surfaces of the bones where they would come in contact with each other and as separate additional buffers. Connecting muscles to the knee and holding the kneecap in place are fibrous cords of tissue we know as tendons. Below, beginning with a description of bones and ligaments and moving through their relationship with cartilage and tendons, we will explore the basic mechanics of the knee. Then we’ll see how that smoothly running machinery can, like a failing car, lock, grind, grate, and crunch its way to disability. We’ll examine why it happens and what you can do about it.
Use the following troubleshooting chart to identify what’s bothering you and your knee. Did you have immediate (acute) pain after the injury? Or is a dull pain always present (chronic)? Did your knee swell within the first twenty-four hours or only later? When the injury occurred, did you hear a pop, or do you hear one when you notice the pain? Do your knees lock? Can you sense a grinding, or do they simply give way? Think about where the pain you feel occurs, and use that as a general guide. Then use the chart to narrow down the types of ailments typically related to that kind of pain.
After the chart, you’ll find explanations covering common knee and hamstring problems by the location of the pain—the knee in general, the kneecap in particular, the sides of the knee, and the front and back of the knee.
If you need a physician to diagnose your knee ailment, consult “The Snap, Crackle, and Pop of Knee Injuries” for a list of questions to consider together.
This is a section from Dr. Jack E, Jensen’s book The One Stop Knee Shop. Read the next section The Kneebone is Connected to the Thighbone.