Swollen Knee

The swollen knee can be red and/or warm to the touch, but that’s not always the case. The look and feel of the knee depends on the underlying cause of the swelling. The knee may also change its shape, become bigger or grow bulges.

Causes of swollen knees

The most common causes of a swollen knee are easily treated and not causes for alarm.However, a swollen knee can also be a sign of an underlying issue that may need to be treated, either medically or surgically. Sometimes, it’s also relevant to change factors in your lifestyle.

Here are the six most common causes of a swollen knee:

1: Injury and overuse

Trauma to one or several of the parts in the knee can cause fluid or blood to run to the joint, resulting in swelling. The trauma doesn’t have to be a major one. It may be small or it may be the result of a long time’s overuse, making it difficult to say when or why exactly your knee started to swell.

Swelling as a result of an injury can occur as late as 36 hours after the injury happened.

If the swelling is a result of overload of the joint for a longer period of time you may need to take a look at your daily habits. Perhaps you need to lose weight, exercise differently, or choose shoes that absorb shock better.

2: Arthritis

Osteoarthritis and rheumatoid arthritis are the most common types of arthritis to cause swelling and pain in the knees. Osteoarthritis is the result of wear and tear over the years. It causes the cartilage between the bones to break down, making the knee joint stiff and painful.Rheumatoid arthritis is an autoimmune disease that causes the body’s own immune system to attack the joints. In this case, you will often experience pain in other joints as well. Septic arthritis and reactive arthritis may also be the cause behind your swollen knee, although these diseases are more rare than osteoarthritis and rheumatoid arthritis. Septic arthritis and reactive arthritis are caused by infections. This means they are not chronical like osteoarthritis and rheumatoid arthritis.

3: Bursitis

A swollen knee can be caused by an inflammation of one or more of the shock-absorbing bursae within the knee. The bursae are fluid-filled sacs that reduce friction in the joints. Non-septic bursitis often occurs after overuse. It can be painful, though that’s not always the case.Septic bursitis is caused by a microorganism and causes pus and fluid to gather within the knee, making it swollen and sore.

4: Gout and pseudogout

Gout is also called inflammatory arthritis. Gout occurs when small crystals of uric acid accumulate within the joint. The sharpness of the crystals cause stabbing pains and often the knee swells up, making the joint stiff and sometimes red.

Pseudogout has many of the same characteristics as gout, the main difference being the formation of calcium pyrophosphate crystals in the joint, and not uric acid crystals.

5: Baker’s cyst

Swelling in the back of the knee is most likely caused by a Baker's cyst, or popliteal cyst. The cyst typically forms after a longer period of swelling in the knee and the underlying cause is usually arthritis or a cartilage tear.

A Baker’s cyst is a fluid-filled cyst that causes an often visible or at least palpable bulge behind your knee. It is often accompanied by a feeling of tightness in the back of your knee that gets worse when walking around or trying to bend or stretch the knee.

6: Plica syndrome

About half the population has remnants of the development of the knee in the embryological phase. These remnants are called plicae and are shelf-like membranes within the knee joint.

If one or more of the plicae become inflamed and irritated it leads to swelling, pain, clicking, popping, and difficulties fully bending and stretching the knee. Often the syndrome gives you a sense of instability when walking upstairs, downstairs or on slopes.

Pain relief

• Acute swelling and soreness of the knee joint should be treated with RICE - Rest, Ice, Compression, and Elevation. Ice packs on the joint can make the swelling go down and and reduce the pain. Try an ice pack (or a bag of frozen peas wrapped in a towel) for 15-20 minutes at the time, three to four times a day.
• Pain medication can be helpful in the initial phase of the swelling if pain in the knee makes it hard for you to keep up with your daily routines. Pain medication such as NSAID (Ibuprofen) and paracetamol should have some effect on the pain. Ibuprofen also has an effect on any inflammation in the joint.
• Resting the knee several times a day can relieve some of the discomfort and pain. But don’t rest too much, as it can weaken the muscles and make your pain even worse and make the joint prone to more injuries and pain in the future.

Exercise

If you have no fever, visible bulges, or severe pain, exercising as much as the swelling and pain allows will likely speed up the healing process. Exercise increases the circulation in and around the joint, which has a positive effect on the body’s ability to heal itself.

Often a swollen knee needs time to recover, though, so make sure not to “push through the pain” too much. Turn down the intensity of your training while the knee is healing and take small breaks between the exercises. If working out makes the pain worse, make sure to give the knee some rest and turn down your exercise a little more.