As a rheatologist, I see joint pain as a window into your overall health. I can’t tell you the number of times that I’ve assessed a patient’s knee and found something that helped me make a surprising diagnosis. So, today I’m going to let you in on some of these secrets and show you some simple tests that you can do at home right now on your knees that may tell you something new about your health. Let’s start with a quick test. I want you standing in front of the mirror. Turn to the side.
With your knees locked, look closely at the angle of your leg. If your knees bend back more than 10 degrees, we call this genu recurvatum, also known as knee hyperextension. Sometimes this can be subtle, while for others it can be pretty extreme. This suggests that your knee ligaments are lax, which some people call doublejointed. But to understand what this might say about your health, we can’t just stop at the knees. Let’s do some more tests. Put your hand on something flat and then pull your pinky back. Can you get it to
90° or even beyond? Next, take your thumb and try to bring it to your forearm. Unlike the others, this one I actually can do. Next, check your elbows. Did they hyper extend over 10°? And your final challenge is to place both of your palms flat on the ground without bending your knees. These are all part of a scoring system called the biteon score. You get one point per joint maneuver. And if you have at least four or five points, depending on your age, we would say that you have generalized joint hypermobility. So,
what does that say about your health? Well, for anyone with hyper mobility, it’s critical to stabilize the muscles around the joint to provide stability, which will also prevent pain and injury. But for some people, it might suggest a genetic condition like Ellers’s Danlo syndrome. And in that case, you’d likely also see other characteristics like very stretchy skin or fragile skin that bruises easily. Okay, on to our next test. Again, I want you standing in front of the mirror with your ankles
together and your knees straight. Do you see a gap between your knees? A small gap can be normal, but if it’s more than about three fingers wide, we’d say you have januum, which is just Latin for bow-legged. You may have noticed that babies sort of stand like little cowboys with their knees apart and feet wide. At that age, bow legs is totally normal. But sometimes your legs can start to bow as an adult. And this is often a sign of osteoarthritis, which some people like to call wear and tear arthritis. Now,
check out this X-ray. This is what a normal knee should look like. See that black space between the bones? That’s your cartilage, which is invisible on X-ray. As you develop arthritis, that cartilage wears away, and the bones get closer and closer together. The cartilage here wears away faster. As the cartilage wears away, it actually changes the angle of the knee. And this is how you can become bow-legged. And it’s a vicious cycle. The more bowed the leg becomes, the more stress is placed
on that already damaged inner knee, accelerating the arthritis. But what does osteoarthritis say about your overall health? Well, first of all, this idea of wear and tear is far too simplistic. Sure, mileage on the joint may play a role, but every part of your joint is alive. Even your cartilage has tiny cells called condondraittes that help maintain its health. The major enemies to your joint health are chronic inflammation and metabolic problems. Osteoarthritis, especially early in life, is strongly associated with
diabetes and high cholesterol. And it’s also associated with higher rates of kidney disease, heart disease, even mental health conditions compared to the general population. So what does that mean for you? Well, if you’re diagnosed with osteoarthritis of the knee, particularly before the age of 50, I think of it as an opportunity, maybe even a wakeup call to look at your overall health as a whole. But sometimes when we see bow legs in an adult, it isn’t actually the cartilage that’s
breaking down. It’s the bone itself. This is Padet’s disease. And to understand what’s going on here, you need to understand the normal life cycle of our bones. So, everybody knows that if you break a bone, it’ll heal over time. But did you know that your skeleton is constantly being recycled? In fact, there are tiny cells that are constantly breaking down and rebuilding your bones in a process called remodeling. And you could say that most adults pretty much have a brand new skeleton about every 10 years or so. But
in Padget’s disease, the problem is that this remodeling process goes into overdrive. Way too much bone is broken down and then those bone building cells try to frantically lay down new bone, but the result is chaotic and disorganized. It’s like trying to make a wall by haphazardly throwing bricks down. The wall’s not only going to be weaker, but it’ll also be bigger for the same amount of bricks. And this is basically why bones become bigger and thicker in pads disease. And this is a
classic deformity that we see called saber tibia. You can imagine how that weaker bone warps under the body’s weight, giving it that bow-legged appearance. Next, I’m going to tell you about a 44year-old man who was seen by a joint specialist for mysterious knee pain. On exam, his knees were definitely swollen. But what really raised concerns were that his nails looked like this. This is called clubbing. And it’s actually really easy to test on yourself. Just put the backs of your fingernails together like this. If you
can see a diamond- shaped gap, that’s normal. If you can’t, we call that clubbing. And because that doctor noticed finger clubbing, he suspected something far more concerning was at play rather than just run-of-the-mill arthritis. So, we ordered a special test called a bone scan. It works by injecting a special radioactive tracer that sticks to areas with increased bone activity, which then gets detected by a scanner. And these are the patient’s results. See those areas that have lit
up on his skeleton? That’s called perryostitis, meaning inflammation of the thin layer of connective tissue that covers the outer surface of the bone. This triad of findings, arthritis, clubbing, and perryostitis are classic for a condition called hypertrophic osteoarthropathy. And unfortunately, most of the time this is caused by a hidden cancer. As it turned out, this patient had undiagnosed lung cancer, and it might have been missed if his doctors had just focused on his knee symptoms without considering the underlying
cause. In the same way, autoimmune diseases that cause knee arthritis can get missed if we only focus on the knee pain and don’t consider the other symptoms that could be related. This is called autoimmune inflammatory arthritis, and it’s when your own immune system attacks and destroys your joints. This is what I specialize in. So, I’m going to tell you exactly what you need to watch out for. First off, I always like to ask my patients about what I call the jelling phenomenon. You can
think of it sort of like making Jell-O. When gelatin is hot, it becomes liquid and moves easily. And when it cools down, it firms up and becomes more stiff. And that’s sort of what it’s like to have inflammatory arthritis. When your knees are cool and you haven’t been moving around, particularly in the morning, you have a lot of pain and stiffness lasting at least 30 minutes. but often lasting for hours and those symptoms improve with movement. So if your symptoms fit that pattern, we need
to look for other clues to make a diagnosis. Here are a few examples. Let’s say you have knee pain associated with bowel symptoms. My biggest concern is inflammatory bowel disease like Crohn’s disease or ulcerative colitis. So, I’d be looking for other signs like a skin condition called aiththemmaosum, which shows up as these painful lumps on the shins or painful mouth ulcers or a painful red eye called acute anterior uvitis. Here’s another one. Knee pain in someone complaining of itchy ears. That
could be related to psoriasis. Psoriasis is a skin condition that usually shows up as red patches with silvery white scales on top. Typically, we’ll see this over the elbows, knees, or scalp, but sometimes it’s hiding in places like inside the ear or in the belly button. Your nails are another great place to look for psoriasis. You may notice pits like this. Having one or two pits isn’t a big deal, but if you have at least 20 across your nails, that’s more concerning. Or your nails might start
separating from the nail bed, which we call anolyis. And the arthritis associated with psoriasis, which we call seroriatic arthritis, is no joke. Your entire finger can become so inflamed that we call it dactylitis or sausage finger. And persistent inflammation can eat away at the bone leading to erosions like this. As a result, some people develop really devastating deformities. We actually call this arthritis mutil. Here’s another one. Knee arthritis associated with swelling and stiffness
in the hands. So these knuckles, these rows of knuckles here, but not these little ones, only these knuckles, that can be a sign of rheumatoid arthritis. And if it’s left untreated, that can lead to some other very distinct deformities in the fingers and hands. I’ve got so many others. I could go on about this all day. Knee pain with a butterfly rash could be lupus. A daily fever and a rash like this during the fever could be adult onset Stills disease. And if your skin becomes tight and hard, and if your fingers look like
this in the cold, it could be sclerodma. So, the take-home point is that sometimes knee pain is just a symptom of a more serious problem. So, it’s important to keep track of your symptoms, and I’d highly recommend taking pictures of any skin changes because they may all be connected. Now, I’m sure some of you are wondering about that popping sound that you may sometimes hear coming from your knees and whether you should be worried about that. Not to worry, I cover that in detail in a separate video that I’ll
link right up here. Okay. Now, here’s a cause of knee pain and swelling that’s on the rise, and that’s Lyme arthritis. It starts with a bite from an infected tick carrying one of the bacteria that causes Lyme disease. In North America, that’s usually borillia burgdorphery. The classic warning sign is a target-shaped rash called athemma migrants. But not everyone sees it, and not everyone gets treated in time. If the infection goes untreated, about 60% of people will go on to develop lime
arthritis. But the tricky part is that those symptoms of arthritis don’t show up for months after the initial tick bite. The knee is the most common joint to be affected. It’s usually just one knee and it can cause massive swelling. But Lyme disease doesn’t just stop at the joints. It can cause inflammation of the facial nerves leading to Bell’s palsy. It can cause menenitis or in rare cases it can even cause inflammation in the heart which can lead to sudden cardiac death. Tragically, this happened
just a few years ago to a 37year-old man here in Canada. Unfortunately, Lyme disease is spreading. Warmer temperatures are allowing ticks to expand their territory to places that never were considered high- risk before. If you do find a tick, you want to remove it right away. And if there’s any chance that that tick has been there for at least 24 hours, you need to talk to your doctor right away because a single dose of antibiotics can prevent the infection before it starts. Okay, now let’s focus on things you might see in
and around your knee. This is called a zenthoma, and it’s basically a fatty plaque in your skin. They’re usually asymptomatic, but that doesn’t mean you can ignore them because those same fatty plaques may be building up in the arteries of your heart. Now, the location of these bumps can be helpful. If you see these over your knees or over the back of your ankles, over the Achilles tendon, this could be a sign of familial hyper cholesterolmia, which is a genetic cause for very high LDL
cholesterol. But you may also spot these on the shoulders or the buttock, and that’s typically associated with diabetes or fatty liver disease. Now, in comparison, if you see these lumps on your knees, fingers, or toes, it can almost certainly tell you about the cause of your joint pain. These are called gouty toephi, and they’re made up of these beautiful uric acid crystals. The big toe is the classic location for a gout flare, but it’s really common to see it in the knee as well. In fact, I
often have patients come to the hospital because they’re in so much pain that they can’t walk. I give them a steroid injection and the next day they’re ready to sprint out of the hospital. They’re so happy. Honestly, it’s it’s one of the best parts of the job. Basically, this happens when uric acid levels in the blood get too high. This may be due to a genetic condition, especially if you’re affected at a young age, but it can also be the first sign of chronic kidney
disease. Normally, your kidneys flush out excess uric acid through the urine. But if they become damaged, uric acid starts to build up in your blood. They can also deposit into the joints which is what causes severe inflammation and pain and over time it can lead to severe joint damage. Here you can see something called a rat bite erosion and it’s classic for gout but it gets worse. These crystals can also deposit into the tissue of the kidneys which can lead to kidney failure and they can also
irritate blood vessels which has been linked to an increased risk of cardiovascular disease. So, in order to protect your joints, kidneys, and heart, it’s important to recognize the signs of gout so that it can be treated properly with dietary changes and medications as needed. But gout isn’t the only cause of a red, hot, swollen joint. In fact, the first thing I always want to rule out in that case is an infection inside the joint called a septic arthritis. You know, this is actually considered a
medical emergency because even when it’s treated properly, a septic joint has a death rate of about 10%. And usually this is due to sepsis when your body has such a strong reaction to an infection that your organs start shutting down. But even in a stable patient, it’s considered a surgical emergency because these infections can rapidly destroy cartilage and bone and that can lead to permanent disability if the knee isn’t washed out and drained urgently. I’ve heard some orthopedic surgeons say that
time is cartilage. And that time frame could be as little as 8 hours. So, the take-home message is that if you suddenly develop a red, hot, swollen knee, especially if you’re feeling unwell or have a fever, you need to get to the nearest emergency department right away because it could be an infection. But sometimes when you get to the emergency department and we’re drawing fluid out of the knee to look for an infection, we actually find that the knee is filled with blood. This is called a hemarthosis. Now, unless there
is some serious trauma to the knee, this usually suggests that the body is having some difficulty forming clots to stop the bleeding. In adults, sometimes they’re taking too much of their prescribed blood thinner. In kids, we always think of a genetic condition called hemophilia, where they don’t produce enough of a specific clotting factor, but sometimes it’s the first sign of a surprising diagnosis. This 60-year-old man with a spontaneous hemosis was diagnosed with scurvy. That’s because without enough vitamin C,
blood vessels become fragile and more prone to bleeding. And for this man, his swollen knee was the first sign of kidney cancer. Unfortunately, the cancer had spread to the bone and invaded into the knee, which led to the bleeding. Aside from being an important clue, it’s really important for us to know if there’s blood in a joint because it can be extremely damaging. While it may not be as harmful as a bacterial infection, if it’s not evacuated quickly, it can lead to permanent joint damage. So,
while knee pain is common, there are certain symptoms that you should never ignore. And some of those symptoms that should bring you to the emergency department right away are if the pain and swelling come on all of a sudden, if it’s waking you up from sleep, if you have a fever, or if you can’t bear weight on that joint, meaning you can’t even walk. Those are reasons to go to the emergency department. It might save your knee or even your life. Now, if you’re curious to learn about a rare,
life-threatening, but ultimately curable cause of chronic knee pain, then I’d recommend watching this medical mystery next. Stay curious, stay healthy, and I’ll see you in the next video. So, bye for now. [Music]
