Knee Arthritis

The knee joint is formed by the femur (thighbone), tibia (shinbone), and patella (kneecap). The ends of these bones are covered with cartilage, which acts as a cushion and allows smooth movement. The joint is also lined with a thin membrane that produces fluid to help lubricate motion.

Arthritis means inflammation and breakdown of a joint. In the knee, the most common form is osteoarthritis. This type is related to gradual wear and tear over time. As cartilage thins, the joint space narrows. Bone spurs may form, and the joint lining can become irritated. These changes contribute to pain and stiffness.

Other forms of arthritis can also affect the knee. Rheumatoid arthritis is an autoimmune condition in which the body’s immune system attacks the joint lining. Post-traumatic arthritis may develop after a previous knee injury, such as a ligament tear or fracture. Regardless of the type, the result is damage to the joint surfaces and difficulty with normal movement.

Symptoms tend to develop gradually and worsen over time. The most common complaint is pain. At first, discomfort may occur only after activity, such as long walks or standing for extended periods. As the condition progresses, pain may become more constant and even present at rest.

Stiffness is another common symptom. Many patients notice that the knee feels tight in the morning or after sitting for a while. It may take several minutes of movement before the joint loosens up. Swelling can occur due to irritation within the joint. The knee may appear puffy or feel warm.

Reduced range of motion is also typical. Bending or straightening the knee fully may become difficult. Some people describe a grinding or clicking sensation when moving the joint. In more advanced cases, the knee may feel unstable or as though it could give way.

These symptoms can interfere with everyday activities. Climbing stairs, getting in and out of a car, kneeling, or walking long distances may become challenging. Over time, reduced activity levels can impact overall health and quality of life.

Knee arthritis most commonly develops due to a combination of aging and joint stress. Cartilage naturally becomes thinner with time. Decades of walking, running, and other weight-bearing activities place repeated stress on the knee joint.

Certain factors increase the likelihood of developing knee arthritis. Age is a major risk factor. The condition is more common in individuals over 50, although younger adults can also be affected, especially if they have had previous injuries.

Excess body weight adds extra pressure to the knee joint. Even a small increase in weight can significantly raise the load placed on the knee with each step. This added stress can accelerate cartilage wear.

Prior knee injuries are another important cause. Ligament tears, meniscus injuries, or fractures can alter the way the joint moves. Even after healing, changes in joint alignment or stability may increase the risk of arthritis later in life.

Family history can also play a role. Some individuals are genetically predisposed to cartilage breakdown or joint problems. Inflammatory conditions such as rheumatoid arthritis can damage the knee joint more rapidly than wear-and-tear arthritis.

Repetitive high-impact activities, especially over many years, may contribute as well. Occupations or sports that involve frequent squatting, kneeling, or heavy lifting can increase strain on the knee.

At OrthoIllinois, the process begins with a detailed discussion of symptoms. Patients are asked when the pain started, how it has changed, and what activities make it worse or better. Information about past injuries, medical conditions, and lifestyle factors helps guide the assessment.

A physical examination involves checking the knee for swelling, tenderness, range of motion, and alignment. The provider evaluates how the joint moves and whether there is grinding or instability. Observing how a patient walks can also provide important clues.

Imaging studies are often used to confirm the diagnosis. X-rays are the most common test. They can show narrowing of the joint space, bone spurs, and changes in bone shape that are typical of arthritis. In some cases, advanced imaging such as MRI may be recommended to assess cartilage, ligaments, and other soft tissues in greater detail.

If inflammatory arthritis is suspected, blood tests may be ordered to look for markers of autoimmune disease. The goal is to determine not only whether arthritis is present, but also what type it is and how advanced it has become.

Accurate diagnosis is essential because it guides treatment decisions. Early identification allows patients to begin strategies that may slow progression and reduce symptoms. Even in more advanced stages, understanding the extent of joint damage helps outline appropriate options for relief and improved function.