Knee pain is one of the most common musculoskeletal problems in the world. In the older population this may be result of osteoarthritis. In younger active adults this is often caused by a phenomenon called Patellofemoral Pain Syndrome or “PFPS”. This is simply a fancy way to say that a person has anterior knee pain or knee pain around their knee cap. These injuries are non-traumatic, involve no structural damage, but can result in significant amounts of pain and dysfunction. In between 3-6% of individuals will experience PFPS. This doesn’t seem like a lot, but if you’re in a group fitness class with 20 other individuals, odds are that someone there is dealing with this problem right now.
PFPS is most accurately diagnosed with a thorough musculoskeletal exam. Since there is no structural damage, imaging does not provide reliable diagnostic accuracy. The most sensitive test with PFPS is pain with squatting. Individuals will also often experience pain with stairs, after prolonged sitting, and stiffness/pain with knee flexion.
Now this brings us to an interesting and common misconception. My knee hurts worst when I squat, so squatting must be bad for my knees right?
This way of thinking is similar to saying “My tooth hurts when I eat, eating food must be bad for my teeth. Should we stop eating food? No, that’s absurd. A normal person will realize that pain with eating is just a symptom of some other problem. They call their dentist to explore the root cause (pun intended) and fix the problem. Knee pain is no different. Pain with squatting is a symptom of a deeper problem. For human function, movement, and longevity the capacity to squat is nearly as important as food consumption. Don’t think so? Tying your kid’s shoes requires a squat. Getting on/off the toilet…you guessed it. Squatting. Getting the frying pan from the bottom cabinet that always seems to be in the far back…you get the point. You should be able to squat without pain.
While I’m on this soap box (it’s my blog ya know), let’s also debunk the myth that deep squatting is bad for you knees. Research indicates that compressive forces transmitted through the knee are greatest at and around 90 deg of knee flexion. Now deep squatting isn’t for everyone, but the idea that it is bad for you is unsubstantiated. You’re placing more stress through your knees getting off the toilet than doing a deep squat. Mic drop.
Now that I have that off my chest, here are 3 keys to dealing with non-traumatic knee pain.
1. Hips don’t lie
Shakira could have been a great PT in another way less interesting lifetime. In my PT career there is one thing that consistently shows up in evaluating athletes and adults with non-specific knee pain. This is that they ALWAYS have a deficit in hip abduction or rotational strength. Always. I’ve seen it so many times that I’d bet my license on it.
What do your hips have to do with your knees though? You’re asking the right questions.
Our legs/arms are all part of what is affectionately called a “kinetic chain”. This means that as you run,/jump/squat force is transferred up and down your entire lower extremity. This means that our hips, knees, and ankles are much more connected than we think.
Hip abductors and external rotators are critically important for stabilizing the femur and preventing excessive valgus (inward motion) or internal rotation. This allows the patella to glide smoothly between the femoral condyles. When there are significant bio-mechanical abnormalities, the line of pull of the patella is changed and can lead to irritation, inflammation, and pain around the knee cap. Strengthening these stabilizing muscles is a crucial and key first step to improving knee pain.
Here are a couple exercises that can be great for targeting these tissues.
2. Quads. 4x the trouble
“Quads are just biceps for weightlifters”. I jokingly made this statement in the gym last week to a fellow Crossfitter. It’s kind of true though. Quads are vital for human performance in and out of the gym. They look pretty cool too if they’re developed enough to be busting out of your gym shorts. I wouldn’t know.
When it comes to anterior knee pain, you can’t overlook the quads. It can be tricky because the impact of this muscle group on anterior knee pain can vary between cases. The knee functions properly when the ratio of strength between the quadriceps and hamstrings are balanced around 3:2. In a clinical setting this is impossible to test without an isokinetic machine, so it can take a bit of investigation. Bottom line is this, your quads can be a problem if they are too weak or if they are way too strong in relation to your hamstrings. For 99% of people quad weakness and tightness is the primary issue. Every once in a while, I’ll see a weightlifter with quads for days that is overly quad dominant and is impacting their knee pain. No offense, but more than likely that is not you. It’s certainly not me.
Here are a couple great exercises for addressing the quad in relationship to knee pain.
3. Foundations are foundational.
We’ve already established the concept or idea of the kinetic chain. For anyone dealing with nagging knee pain we can’t forget about the primary interaction point of the leg with the world. That would be the foot and ankle complex. Foot and ankle weakness and instability can be large drivers of knee pain and patellofemoral dysfunction. Deep diving into the foot and ankle complex is worthy of a blog of it’s own, but for today we’ll simplify it into two primary functions.
1. Pronated position of the foot (flat foot): This position is necessary for absorbing shock after heel strike as you transfer force from heel to toe. Your arch softens, dissipates forces, and allows safe force transfer before push-off.
2. Supination of the foot (high arch): This position is necessary for creating a stiff rigid foot that is perfect for pushing off and generating force.
Due to the shoes that we wear, lack of targeted strengthening, and high rate of sedentary jobs our feet and ankles are weaker than ever. For many people this means that they are stuck in pronation (flat foot position) due to intrinsic foot weakness. This directly impacts the knee because every step, jump, squat is now performed on a soft and unstable foot. Imagine trying to jump as high as you can in a sand pit. You’re probably not going to impress the NBA scouts. Why? It’s difficult to generate force without a stable foundation. This is exactly what happens with our foot and ankle. If pain or problems do not manifest there, it is common for them to present further up the chain at the anterior knee. The knee is now under increased stress and poor positioning due to the instability of the ankle/foot.
Here is a basic foot/ankle stability exercises to try and improve this problem.
In conclusion, PFPS and anterior knee pain is a big problem that often caused more by the hip and ankle than the knee itself. These injuries are successfully managed by movement-based professionals who are able to assess these movement patterns and dysfunctions. Remember that joints don’t work in isolation and the site of pain is not always the site of the problem. Here’s to happy knees.
Stay Kinetic Friends.
References:
Aishwarya Gulati, Christopher McElrath, Vibhor Wadhwa, Jay P Shah, and Avneesh Chhabra. Current clinical, radiological and treatment perspectives of patellofemoral pain syndrome. The British Journal of Radiology 2018 91:1086.
Dr. Levi Kerby is a physical therapist, orthopedic certified specialist, and owner of Kinetic Performance and Rehab in Winston-Salem, NC. He enjoys fly fishing, guitar, various forms of fitness, and treating active and motivated individuals.
If you're dealing with an injury or pain, you can contact Kinetic Performance and Rehab directly below.
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