Frequently Asked Questions about Knee Arthritis

Author: Joshua Steere, MD

Why does my knee click or pop?

Knees can make noise from time to time, especially knees with osteoarthritis. This can be from a variety of causes, most of which are not cause for alarm. In knees with osteoarthritis, the smooth cartilage surface on the end of the bone wears down and becomes damaged, making the ends of the bones uneven and rough. When the knee bends and straightens, these rough surfaces move past each other and can make a clicking or snapping sound. Osteoarthritis can also cause the lining of the knee joint to become thickened and inflamed. This is called synovitis. Sometimes clicking or snapping can be caused by this thickened synovium rubbing over the edges of the bones and knee cap. Concerning symptoms would be popping that leads to a significant amount of painful swelling or instances where the knee locks up and cannot be bent or straightened. These symptoms should be evaluated by your doctor.

Why is my knee swollen?

Many people with knee osteoarthritis will feel the knee swell from time to time. The knee joint normally contains a small amount of fluid called synovial fluid which helps lubricate the knee as it moves and provides nutrients to the cartilage. Knees with osteoarthritis, however, often make extra synovial fluid that can cause the knee to fill up and feel swollen and tight. After periods of increased activity, the swelling may increase if the knee is aggravated and painful. Sometimes the synovial lining of the joint can also become thickened and inflamed, causing the knee to feel puffy. Helpful treatments for knee swelling are compression stockings, ice, elevation, rest, and anti-inflammatory medications. Knee swelling can also be caused by other conditions such as traumatic injury, infection, or gout. Talk to your doctor if you have abnormal knee swelling.

What is a Baker’s cyst?

A Baker’s cyst (also known as a popliteal cyst) is common in knees with osteoarthritis. If the knee has extra fluid from inflammation, that fluid can pool up in the back of the knee. When that fluid pools up, it can cause an outpouching of the joint capsule in the back of the knee. This outpouching is referred to as a Baker’s cyst. Though a Baker’s cyst is not dangerous, it can get larger or smaller depending how much fluid is in the knee. It can be uncomfortable and make the back of the knee feel tight. Draining the fluid is not routinely recommended because the fluid in the knee joint often flows back into the area. Treating the underlying osteoarthritis is often the best way to treat a Baker’s Cyst. This can reduce the inflammation and swelling that causes discomfort in the back of the knee.

Why does my knee give out?

Knees with painful osteoarthritis can sometimes feel like they give out or buckle. This is often caused by an involuntary response to pain where the quadriceps muscle becomes weak. The quadriceps muscle is in the front of the thigh. It attaches to the kneecap and helps keep the knee straight when walking. Just as the body will involuntarily pull the hand away from a hot surface, the body sometimes responds to pain in the knee by involuntarily making the quadriceps muscle give out. When this happens, the knee can feel unstable. This can be dangerous if it happens going down stairs or if it causes loss of balance. If this happens often, using an assistive device like a cane, crutches, or a walker can help prevent injury. Often these buckling episodes can be improved with pain control, reducing the inflammation in the knee, and strengthening the muscles around the knee with low impact exercise and/or physical therapy. The knee can also give out due to instability from a ligament injury or tendon injury, so consult with your doctor if the knee feels unstable or if you have had an injury.

If you are struggling with knee pain, please call (215) 600-4714 to schedule a consultation with one of our specialists.

These are other useful links for knee osteoarthritis:

American Academy of Orthopaedic Surgeons (AAOS) - Clinical Practice Guidelines on Treatment of Osteoarthritis of the Knee

American Association of Hip and Knee Surgeons (AAHKS) - Patient Care Library

American College of Rheumatology / Arthritis Foundation Guideline for the Management of Osteoarthritis of the Hand, Hip, and Knee.

US Department of Health and Human Services - Physical Activity Guidelines for Americans


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