Nicholas A. Dinubile - FrameWork for the Knee: A 6-Step Plan for Preventing Injury and Ending Pain

Before embarking on any biomechanical training program, having a basic understanding of the parts involved is more than usefulits critical. You have to know whats involved with movement so you can understand why you should be faithful to the exercises that keep your components humming. And when you know why, your brain will be fully engaged to balance the mind/body component of good health. Yes, the practice of mindfulness can be applied to keeping your knees healthy and functioning optimally.

I know Im partial, but the knee is truly amazing. When I look at sports players who put up with so much every day, and yet dont get injured, I marvel at how ingenious its design is. They, and their knees, jump, twist, pivot, change direction, and land, often seemingly off-balance, at warp speed. One needs to watch the slow motion replays to fully appreciate what has occurred; in fact, there are computerized high-speed biomechanical analysis tools that we now use to better understand the complex biomechanical movement patterns unique to each sport. When all of the parts are fine-tuned, amazing athletic feats are possible for some and the rest of us can get around reasonably well without toppling over.

So without further ado, and mindful of keeping the academics to a minimum, lets scope the knee together.

View of Knee from Front

When people think about the knee, they usually just think about the kneecap, or patella, or a simple hinge structure. However, it takes more than one part to make a hinge, and the knee is even more complex than that. It consists of two distinct joints formed by three bones: the patella and femur (thigh bone) get up close and personal in the patellofemoral joint; and the femur and the tibia (leg bone) do likewise in the tibiofemoral one.

The main part of your knee is where the femur and tibia meet; its the main hinge that is loaded most of the time when you stand, walk, or run, especially on level surfaces. This tibiofemoral area is made up of two compartments: the inner (medial) and the outer (lateral). The patellofemoral area provides the third compartment of the knee, and this is formed by the kneecap and thigh bone. The area of the thighbone that houses the kneecap is called the trochlea. The patellofemoral joint is loaded and relied on even more when the knee is flexed, like when you go up and down stairs, ski, or do squats and lunges at the gym. The patella is interesting in that it is a bone that lives within a muscle-tendon complex, something we call a sesamoid bone (you have a few others of these around your frame). This is a smart design from a biomechanical standpoint in that it increases tendon leverage on the femur during leg extension. It is also a setup for a variety of unique problems that can occur around the oft-temperamental kneecap.

KNEEPAD

Your health hinges on your knees.

When healthy, these three compartments work in unison, smoothly gliding across each other with a coefficient of friction 20 times more slippery than ice on ice. But there are some thorny design problems that are unique to the knee, and when things go wrong, the grinding starts. It can be throughout the entire knee, involving all three compartments equally, or the problem can be selective and isolated to just one or two of the compartments. Im a perfect example. My main tibiofemoral area is pretty good, but, from my old injury, my patellofemoral articulation is shot, pretty much bone on bone, awaiting the parts department.

In addition to the bony architecture, there are plenty of other softer things that can run afoul in the knee.

Ligaments, tendons, and muscles all play a role in knee design, but cartilage tops the list when it comes to picking a lead actor. What will surprise many of you is that there are two kinds: articular cartilage (it looks like the smooth white opaque ball that you might recall seeing at the end of a chicken bone), and the meniscus (fibrocartilage) that most lay people have in mind when they refer to a torn knee cartilage. They are two completely different components. Perhaps this is imprecise terminology, but its important to appreciate the distinction.

Side View of Knee from Outer (Lateral) Side

ARTICULAR CARTILAGE

This frame part is a smooth joint surface cushion that covers the ends of both the tibiofemoral and the patellofemoral joints (or any joint in your body for that matter). Its sort of a cap on the end of the bone surfaces that functions as a cushion so that bone-on-bone doesnt occur. When healthy, the articular cartilage is thick and smooth and looks like newly polished white marble. When damaged, it can start to look like a shag carpet, and if it wears all the way down, you can actually see the bone, or even have a bone-on-bone situation. You will hear more about arthritis (which is a wearing down of the articular cartilage) as well as chondral defects, which are focal areas of damage (like potholes) in the articular cartilage cushion. When your cushion is damaged, it is often the beginning of the end for your knee. (Unless, of course, you do something about it.)

MENISCI

The meniscus is a shock absorber and space filler that consists of rubbery material akin to the body of a clam. Its C-shaped, and theres one on both the medial (inner) and lateral (outer) sides of the knee. The two menisci are appropriately called the medial meniscus and lateral meniscus.

KNEEPAD

Articular cartilage, when healthy, has a coefficient of friction that is 20 times better than ice on ice.

Menisci are protectors of knee joints, and theyre critical for knee congruity and stability because they help create a perfect fit for the articular cartilage cushions of the femur and tibia as they glide and twist across each other. For that reason, we now do everything we can to preserve and protect the meniscus after a knee injury, or during knee surgery, rather than a few years back where, as I said before, the goal was usually to remove the whole thing. One more critical point: Because the menisci are slick and pliable to minimize friction, theyre critical for pain-free motion.

LIGAMENTS

Your knee and its shock absorbers are kept in place by four primary knee ligaments, or taut bands. Theres one on the inner side of the knee (the medial collateral ligament, or MCL) and one on the outer side (the lateral collateral ligament, or LCL) that prevent side-to-side drift. To keep abnormal front-back movement in check, the posterior cruciate ligament (PCL) and the (infamous) anterior cruciate ligament (ACL) crisscross (hence the name cruciate) in the center of the knee.