Excerpts

Step 1 Knee Deep Before embarking on any biomechanical training program, having a basic understanding of the parts involved is more than useful--it's critical. You have to know what's 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 I'm partial, but the knee is truly amazing. When I look at sports players who put up with so much every day, and yet don't 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, let's "scope" the knee together. View of Knee from Front THE BARE BONES 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; it's 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. I'm 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. THE SOFTER SIDE 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 it's 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). It's sort of a cap on the end of the bone surfaces that functions as a cushion so that bone-on-bone doesn't 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. It's C-shaped, and there's 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 they're 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, they're critical for pain-free motion. . LIGAMENTS Your knee and its shock absorbers are kept in place by four primary knee ligaments, or taut bands. There's 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. The four major knee ligaments work in concert to prevent abnormal movement patterns within the knee. Interestingly, almost like strings on a tennis racquet, we are all "strung" with a little different tension; some of us have very tight ligaments, and others (especially females) are more "loose- jointed." If your ligaments are loose, you might do better in yoga class or in the circus, but you are at higher risk for a variety of injuries. . TENDONS Several additional taut bands support front-back stability as they expand and contract with motion: The quadriceps tendon attaches the quadriceps or thigh muscle to the upper part of the patella; the infrapatellar tendon connects the lower part of the patella to the tibia (at an area called the tibial tubercle); and the hamstring tendons run across the back of the knee on both the medial and lateral side. (The calf muscle runs up the lower leg and actually also attaches up behind the knee.) . ILIOTIBIAL BAND (ITB) The ITB consists of fibrous tissue that is similar to a tendon. It's wide and long, traveling from the upper leg muscles of the outer thigh area, across the lateral side of the knee, to the tibia below, where it attaches. . MUSCLES The leg muscles are the pistons and driveshaft, if you will, of the knee machine. You can be sure the quadriceps, hamstring, and calf muscles that are a part of every FrameWork program will be given particular attention in this one because of their connections to knee health. And it doesn't stop there. We are learning that even core and pelvic musculature are critical in maintaining optimal knee function and preventing knee injuries. KNEEPAD Combined, the quadriceps and its tendon, and the patellar and the infrapatellar tendons are called the extensor mechanism of the knee and function as the major muscle-tendon group for it. It's a common source of knee problems for adolescents and young athletes. . NEUROMUSCULAR CONTROL Last (but hardly least when it comes to frame work) is what links all of the above individual anatomical parts together to perform like an orchestra, rather than a group of soloists: neuromuscular factors, a combination of nerves and muscle activity that interacts with the spinal cord and brain, giving your knee and you agility--that proprioception (fine- tune coordination) that we have stressed and will continue to explore in this book. Optimal neuromuscular function is something that can be trained (and lost with injury, casting, aging, or inactivity), and is every bit as important as any major ligament or muscle when it comes to keeping knees healthy for life. "JUST A LITTLE DAB WILL DO YA" There's a final ingredient in the inner workings of Mother Nature's hinge: magical fluid. An undetectable drop of this synovial fluid (the lining of the knee is called the synovium)-- which is all you should have in your knee--just one drop of this awesome WD-40-like lubricant glistens all joint surfaces and carries far more than its weight when it comes to that better- than-ice coefficient mentioned previously. (Anyone who recognizes the title of this section is old enough to be concerned about this fluid because "drying up" is an issue in collagen and brain cells, along with some other cells, as we age.) Synovial fluid also has some components that help nourish and protect the articular cartilage joint cushion, which has no intrinsic blood supply, so it relies on the synovial fluid for its nourishment. Movement and exercise enhance this process by pumping syno- vial fluid into the cushion. Hence my mantra, "motion is lotion." In knees with arthritis, the synovial fluid becomes less viscous and is not as good a lubricant as it is supposed to be. . WEAK LINKS When evaluating a knee case, I always take into account the patient's predisposition toward whatever ailment that presents. Weak links are one of the common threads in this series because they play a role in every aspect of frame health, and they are always part of the frank discussion I have about a knee issue. Time is not a factor when I explain that many of the things that interfere with knee health and function, causing one complaint or another, can be corrected by the patient himor herself, and that those that are beyond his or her control can usually be managed. . JOINT DISCUSSION I have knee patients work on the calf, along with the hamstrings, quadriceps, and hip abductors and adductors. The calf is an assist muscle, especially going up and down stairs. When people have a bad knee like mine, it's so worn that steps and stairs hurt. My body compensates and my calves wind up bigger than they should be (balance, remember?), so instead of using my quad to spring upwards, I use the foot press more than I should. (Sometimes, in response to pain or other brain signals, your amazing body will make little adjustments that might not result in the best biomechanics.) . AGE This is listed first because every age presents its own set of knee problems: Growing children have one part or another that is loose as they mature, and it's not uncommon that a growth plate in a knee bone is waiting around for soft tissue to catch up; mature people have initial wear and tear (with or without symptoms) that will spread unless serious intervention ensues; seniors are candidates for more advanced arthritis and certain fractures with their concomitant issues. In addition to the above specifics, there are some general consequences of aging that threaten every frame: . Probability of injury increases . Severity of injury increases . Time to heal increases . Degree of healing decreases . Cellular and biochemical changes occur: . Bone loses density . Ligaments weaken . Growth hormone production decreases . Collagen is lost and its structural integrity diminished . Neural loss (neuromuscular wiring goes from cable high-speed to dial- up) . Muscle mass and strength diminish, as does reaction time . Loss of proprioception All this adds up to higher vulnerability. Yessiree--age is a biggie when it comes to knees, and it's so big, the next section is devoted entirely to what can go wrong with our knees from our youth on up to our twilight years. . GENDER A weak link affecting half of the population explains a large percentage of the cases I see all the time, so it merits a corresponding share of a knee discussion. It's been proven that up until puberty, boys and girls land the same way from jumps, and from then on, girls start landing differently: Their knees either buckle in slightly or they land more stiff-legged--they're not landing like a cat anymore. (They have a landing gear problem whereby the knees don't transfer as much shock as they should.) JOINT DISCUSSION Knee MRI studies involving the over-60 crowd showed significant issues in the majority of patients, even those without symptoms. Scans of the interior of their menisci showed that, instead of appearing black as healthy menisci do, there was a whitish-grayish material in the center that indicated fatty degeneration. (This was similar to findings on the spinal intervertebral disks we talked about in the previous book about the lower back.) It doesn't take much to go from there to an actual separation of tissue, which we refer to as a degenerative tear. (It's like a tear in a pair of pants--certain movements and twists, even regular ones like a golf swing, will spread it. So a meniscus tear propagates with age and becomes more and more symptomatic.) These types of meniscal tears are very common with aging (as multiple MRI studies have shown), and like gray hair and wrinkles, not all need treatment. Each case must be individualized. Excerpted from FrameWork for the Knee: A 6-Step Plan for Preventing Injury and Ending Pain by Nicholas A. DiNubile, Bruce Scali All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.