Understanding Knee Pain, Part 1
Updated: Jul 17, 2020
One size doesn't fit all
Hi everyone! This is Dr. Michael Hauber and Dr. Patrick Chandler, and we are the newest Restore/Thrive team members.
First of all, we hope that everyone is staying as safe and healthy as possible in these stressful times. As physical therapists and strength and conditioning coaches, we are passionate about teaching our clients how to solve pain, move optimally, grow strong and age gracefully. We know that everyone’s life has been turned upside down these past several months, and for many of us, it has become an opportunity to walk, run, or lift weights more. This is a fantastic mindset, but often a recipe for pain and injury if done too quickly or inappropriately. This is why we want to discuss one of the most common victims of pain and injury: the knee!
Now, before we can dive into how to treat the knee, we first need some understanding of its anatomy and biomechanics.
Why? I just want my pain to go away.
Well, because as physical therapists we know that any of the structures that make up the knee region can be pain generators. This means that "knee pain" is an umbrella term, not specific. It is our job to figure out which of those structures is the pain generator so we can guide you on a path specific to helping that structure heal.
Remember this, if all you ever receive is a generic exercise sheet as an answer to your pain, it will never solve the problem. Our job is to select the movements and exercises specific to your clinical presentation, or your pain and limitations.
Okay, now it’s time to review our knee anatomy. Don’t worry, a trip to a cadaver lab is not required. In our knee region, we have bone, joint capsule, menisci, ligaments, muscles, tendons, bursa, fat pad, plicae, blood vessels, and nerves. No, plicae is not a made-up word. When two bones come together, that is called a joint. The knee region is made up of four bones: the femur, tibia, fibula, and patella.
You also have two joints that collectively represent the knee: the tibiofemoral joint and the patellofemoral joint. The tibiofemoral joint represents the junction where the two condyles or hemispheric extensions of our femur meet two shallow indentations in our tibia. Now we all know we have a kneecap and some of us may have tried some party tricks growing up seeing how far we could move it. Right? The kneecap is called the patella. It slides up and down in a groove directly in front of the tibiofemoral joint, referred to as the patellofemoral joint.
A layer of smooth cartilage lines the end of each bone for protection and shock absorption. The joint is encompassed by a joint capsule. Inside the capsule, you have synovial fluid. This fluid is what maintains the health of our joint by providing nutrients, keeping it lubricated, and helping remove inflammation. Think of it like the oil that lubricates a car engine, the honey-colored oil, not that black crud!
to self: check oil stick.. So the synovial fluid helps lubricate the joint, but the knee needs a lot more help than that to stay healthy. Part of that help comes from two crescent-shaped, fibrocartilaginous structures called menisci. They help correct for the incongruence between the ends of our femur and tibia to provide more stability and cushion to our tibiofemoral joint.
Next, we have ligaments. Ligaments can be intra-articular (within the joint) and extra-articular (outside of the joint). Their job is to protect the joint from going too far in one direction. They do these by basically anchoring themselves from one side of the joint to the other. The knee in itself is a very unstable joint based on the shapes of the bones. The bottom of the femur is very round and the top of the tibia is relatively flat. Therefore, it is heavily reliant on ligaments to help stabilize it from several angles.
Now, most often, the communication from our balance system and neuromuscular coordination around the knee will keep us out of those unwanted, potentially dangerous ranges on the joint. The ligaments are like the emergency brake in a car. So what about muscles and nerves?
Muscles are what attach to the bone and nerves activate the muscle. Ultimately muscles are just inert, meaty tissue. The nervous system is the puppet master, the pianist.
Yeah, I already know all that; but what the heck is a bursa?
Well, the bursa is in itself just a fluid-filled sac. It also contains synovial fluid, just like within the joint capsule. Its job is to sit between structures to keep them from rubbing against each other, otherwise, each time those structures rub together it would be like burning rubber even if you lightly tap the accelerator (it’s absolutely expected when you’re doing donuts though).
Fun fact, we actually have around 14 of these bursae just in the knee region! Now what about a fat pad? Take it at face value, it is literally a pad of fat. Its main purpose is to fill in gaps within the joint space, just like eating ice cream. The contours of our knee joint are very bumpy and incongruent, so our joint capsule needs the help of a fat pad to fill in space. Bursae and fat pads each play a role with shock absorption and protecting the surrounding structure.
Okay, so we now have some idea of the anatomical structures that make up the knee. How do all those parts fit together? Well, they collectively help the knee bend and straighten a total of 145 degrees and rotate up to 45 degrees.
What’s the main purpose of all that motion?
To help distribute force and guide lower body movements. The second our foot touches the ground, the knee is supposed to help transfer that force up to the hip and pelvis and through our core. So, whether we run, walk, climb, squat, lunge, or jump, our knee is involved.
The knee primarily represents a hinge joint, meaning it is not very dynamic at changing directions on its own. Most of our movement variability, or what we think of as graceful movement, is dictated by our more dynamic movers: the hip and ankle, or upstream and downstream from the knee.
Why are we talking about the hip and ankle? This is supposed to be about the knee.
Well, a common mistake with addressing knee pain is to only observe how the knee moves. If you think about a chain-link fence, every chain is dependent on the other one right? What happens if that fence develops a hole in it? It’s probably a safe bet that the links surrounding it undergo a lot more stress then they are accustomed to, and become more predisposed to breaking. This analogy similarly applies to the knee. If you can’t move your ankle or hip very well, whether it’s stiffness, weakness, or some combination, the knee becomes a common victim due to the dysfunctions above and below it.
How does all of this fit into addressing your knee pain right here and now? In order to address pain, we first have to look at you, the organism. We have to look at your fundamental movements or movements that are innate to every human. These include how well you walk, run, squat, lunge, step, and jump.
So...how well do you move? Do you move like Frankenstein or Erwan Le Corre (watch the cool video below), founder of MovNat?
If you move like Frankenstein, but you’re training to run a marathon, we might have a big problem. When you walk, can someone hear you from the next house over, or do you have the soft step of a ninja?
If you have pain with movement, it is important to know what your movement profile looks like to see what movement patterns get a thumbs up and which ones require us to look under the hood. This is where each anatomical structure comes into play so that we pick the best, most specific path forward for you.
Remember, very rarely do generic exercises work. For example, an inflamed bursa is not going to like being pushed on like a tight muscle might. A meniscus tear will not be a happy camper if you just try to squat through it.
As the pain resolves, and you move a little closer to a ninja, then we have to ask a very important question: is your environment rich enough to maintain those fundamental movements, or what we worked so hard to develop in physical therapy? If we address the problem, but your environment still requires a lot of sitting, repetitive tasks, or inappropriate programming, then you might be knocking on the physical therapy door a month later.
So what does our approach typically look like for addressing knee pain? Stay tuned for Part 2 of this series later this month. If you want to learn more about how we help our clients resolve their pain and fully return to the activities they love, click the "Inquire Now" button at the top of the page and we'll schedule a time to talk with one of our docs!