Woman holding her painful knee while thinking of the possible causes of her knee pain

8 Common Causes for Knee Pain

There are a variety of causes for knee pain. As a connection point for some of the largest bones and muscles in your body, the knee is anything but a simple hinge joint. 

Damaging any part of the knee can create one of many possible causes of knee joint pain – so it’s good to know more about how to identify and treat these causes.

You may be wondering: What can cause knee pain without injury?

Causes for knee pain range from degenerative diseases such as osteoarthritis, to cysts and alignment issues. So if you’re feeling discomfort in your knee, it’s important that you understand why that is, and how much of a cause for concern it should be. 

Chronic knee pain becomes more common as we get older, but knee pain is often temporary and fixable. Some types of knee pain will subside with time and some good rest, but many types of knee pain can be a signal to seek treatment from a medical professional.

Of course, the various causes for knee pain aren’t always an alarm bell for major concern – but they can be. Pain is one way your body reminds you not to put pressure on a fragile or injured body part. That being said, the message isn’t always clear.

If you can fix it, you should. But the first step on the road to recovery is identifying the problem.

Today, we hope to provide information on some of the most prevalent causes for knee pain. You may be able to more successfully identify your own knee pain after reading this guide. However, this list is best served as a starting point for a conversation between you and a medical health professional.

8 common causes for knee pain

Here are the most common causes for knee pain. If any of them sound familiar to you, it’s a good idea to speak with your doctor about your symptoms.

1. Osteoarthritis

One of the most common causes for knee pain is osteoarthritis. Osteoarthritis is a condition that can affect all your joints; especially the knees. It happens as you get older and the cushioning in your joints wears down, and it causes pain, stiffness, and difficulty moving.

That cushioning in your joints is called cartilage and it’s rich in collagen protein. Cartilage is important because it stops your bones from grinding against each other as you move.

If you have osteoarthritis in your knee, this can make it harder to do things like walking or bending down. You might also notice swelling, a cracking or creaking sound when you move your knees, or even bony growths around them.

Sadly, osteoarthritis isn’t something that doctors can “cure” medically. It’s best considered a condition to manage. Common treatments include pain medication, diet changes, and lifestyle management – such collagen for arthritis

Surgery may be an option if osteoarthritis becomes severely painful.

2. Knee bursitis

Your knees have many small, fluid-filled sacs inside them. These sacs are called bursae.

Why are they there? 

Bursae help to cushion your knee and reduce friction between your bones, tendons, and muscles. When the bursae get inflamed and swollen, they become one of the possible causes for knee pain. This condition is called knee bursitis. 

Knee bursitis can happen for a few reasons, like knee overuse or injury, or even just old age. You might feel pain, swelling, or stiffness in your knee, and it might be tender to the touch. You might also notice that it hurts more when you move your knee or put weight on it.

These symptoms, particularly if they don’t subside quickly, are an indication that you should book an appointment with your doctor to talk about treatment options. This may include pain medication, supplement usage, or surgery in severe cases.

3. Patellar tendonitis

Patellar tendonitis is another one of the most common causes for knee pain. It is a condition that affects the tendon that connects your kneecap (patella) to your shinbone. 

It's also sometimes called "jumper's knee" because it's common in people who do a lot of jumping, like basketball players or volleyball players. But you don’t necessarily have to play sports to get patellar tendonitis. 

When you have patellar tendonitis, the tendon becomes inflamed and irritated. This can cause pain and tenderness in the front of your knee, and it might hurt more when you bend your knee or jump. 

The good news is that there are things you can do to help relieve the pain and speed up healing. Resting your knee, using ice to reduce swelling, and taking over-the-counter pain medicine can all be helpful. 

It's also important to avoid activities that might make the pain worse, like jumping or running.

4. Patellofemoral Pain Syndrome

Patellofemoral Pain Syndrome (PFPS) is commonly referred to as "runner's knee," and easily makes our list of the most common causes for knee pain. It is a condition that concerns the kneecap and thigh bone (the femur), and can affect anyone – not just runners. 

If you have PFPS, you may feel pain or discomfort in the front of your knee, especially when you bend or straighten your leg. You might also notice a grinding or popping sensation in your knee. The pain can be mild or severe, and it might come and go rather than being constant.

PFPS can occur for a few reasons, like overuse of your knee, an injury, or even just the way your knee is built. Women are more likely to get it than men, and it's also more common in people who are overweight, as the knee has to withstand more weight when moving.

PFPS can be managed with NSAIDs, physical therapy, and in rare cases, surgery to correct the alignment of your joint. 

5. Baker’s cysts

A Baker's cyst, also called a popliteal cyst, is a lump that can develop behind the knee. It's named after the doctor who first described it, and is one of the most common causes for knee pain.

Baker’s cysts are caused by a buildup of fluid in a sac behind the knee. This may be due to injury or arthritis. If you have a Baker’s cyst, you will feel pain or discomfort in the back of your knee, and the general area might feel swollen or stiff. 

This condition is easier to diagnose than some other causes for knee pain on this list: The cyst itself might feel like a soft lump behind your knee. Given its position, however, you may need someone to check for you. 

Like all the causes of knee joint pain on our list, it's important to avoid activities that make the pain worse, like running or jumping. If you have a Baker’s cyst, your doctor may recommend draining the fluid with a needle or, in rare cases, performing surgery to remove it.

6. Infection in the knee joint

Not all causes for knee pain are due to injury or aging. Like any part of your body, your knee can pick up an infection. 

When you have an infection in your knee joint, it means that bacteria or germs inside your knee are what is most likely causing your knee pain. This can happen after an injury or surgery, or sometimes for no obvious reason at all!

What would an infection in your knee feel like? You might feel pain, warmth, and redness in your knee. You might also notice that your knee is swollen and stiff, and it might be hard to move. You might feel like you have a fever, and be generally weak and tired.

If your doctor believes an infection in the knee joint is causing your knee pain, they have a variety of tests at their disposal to confirm what's going on. Then they can prescribe antibiotics or other medicine to help get rid of the infection. 

Meanwhile, it's important to rest your knee and avoid putting too much weight on it. Your doctor might suggest using crutches or a brace to help keep your knee stable while it heals.

7. Osgood-Schlatter disease

While osteoarthritis is commonly associated with the elderly, Osgood-Schlatter disease is most common in children and teens who are going through growth spurts.

With Osgood-Schlatter disease, you may feel a lump or bump on the front of your knee, right below your kneecap. The general area might feel sore or tender if you touch it, and it might be hard to bend or straighten your leg without feeling pain. 

Osgood-Schlatter disease can also cause extra pain when you're running, jumping, or doing other activities that put stress on your knees.

If your doctor believes you have Osgood-Schlatter disease, they may recommend over-the-counter pain medicine or ice to manage discomfort.

8. Torn ligaments

A torn ligament is one of the easier causes for knee pain to identify quickly, as the pain will occur sharply the moment the ligament becomes torn after a difficult impact, or sudden twisting movement. You might also hear a popping or snapping sound at the time of injury.

Ligaments are built with collagen protein, so they’re strong, stretchy tissues that connect your bones together. They help keep your joints stable. When a ligament in your knee is torn, it means that the collagen connective tissue has been stretched or ripped apart. 

Your body will go to work right away to heal the wound, but with ligaments this can take time – upwards of 8 to 12 months.

If you have a torn ligament in your knee, you might feel pain, swelling, and stiffness in your knee. It might be hard to walk or put weight on your knee for a considerable amount of time, and it might feel like your knee is giving way or buckling when you try to move it. 

If you think you have a torn ligament, it’s important to get a proper diagnosis from your doctor. Depending on how badly the ligament is torn, they may recommend rest, ice, NSAID, physical therapy, or surgery.

Surgery is more common if the ligament is completely torn, and if you want to return to strenuous activities or sports upon recovery. Otherwise, physical therapy and collagen supplementation may be enough to aid your recovery. 

Guarding against knee pain

Given the wide variety of causes for knee pain, there’s a lot to consider. Of course, preventing the causes for knee pain is preferable to finding cures.

Knowing what to take for knee pain can be tricky, but the best way to protect against the common causes for knee pain may be a collagen protein supplement.

Why? Healthy tendons, ligaments, and cartilage are vital for overall knee health, and collagen protein is the main building block of all those connective tissues. 

As the go-to protein for reinforcing our cells, healing wounds, and providing flexibility and support to joints, it’s important that we’re always well stocked-up with collagen.

Can collagen cure knee pain? No, collagen is not a medicine or a painkiller, but it does provide the ideal conditions for your body to heal the root cause of your knee pain.

Collagen will also go hand-in-hand with recovery after surgery. After surgery, the body often requires a protein surplus so it can continue the job of healing the affected areas. Collagen has been shown to help reduce recovery time for knee surgery.

Choosing your collagen supplement

When choosing a collagen supplement, you want to look for a hydrolyzed collagen supplement. Hydrolyzed protein has been broken down so it’s easy to digest quickly. 

Any supplement that contains large molecules won’t be effectively digested by your body, so you’ll miss out on many of the benefits of your supplement. For that reason, hydrolyzed collagen is a must.

You can even go a step further and look for medical-grade collagen like the supplements at ProT Gold. These supplements have been rigorously tested, are FDA approved, and are trusted for use in medical facilities across the country. 

Whether you are trying to heal swiftly after surgery, protect the health of your tendons and ligaments, or reduce pain and inflammation in your knees, a high-quality, hydrolyzed collagen supplement can help.