Understanding Your Joints

What Causes Osteoarthritis?

Osteoarthritis develops as the cartilage cushioning the joints gradually wears down over time, but this process actually involves several tissues working together rather than cartilage breakdown alone. As cartilage becomes less effective at cushioning the joint, the underlying bone can also change and adapt, and the joint lining can become mildly inflamed, contributing further to discomfort and stiffness.

Age is one of the most significant risk factors, simply because joints have more time to accumulate wear and undergo these gradual changes the longer a person lives. Previous joint injuries also meaningfully increase risk, sometimes leading to osteoarthritis developing years or even decades earlier than it might have otherwise in that particular joint.

Repetitive stress on a joint, whether from certain occupations involving frequent kneeling, squatting, or heavy lifting, or from certain sports and high-impact activities, can also contribute to earlier or more significant osteoarthritis. Excess body weight is another well-established factor, since carrying additional weight increases the mechanical load placed on weight-bearing joints like the knee with every step. Genetics plays a role as well, and joint alignment or shape can sometimes concentrate force on a smaller area of cartilage, accelerating wear in that specific location over time.

What Are the Symptoms of Knee Osteoarthritis?

Common symptoms of knee osteoarthritis include joint pain that typically worsens with activity and improves with rest, particularly in the earlier stages of the condition. As osteoarthritis progresses, however, some people begin experiencing pain even during periods of rest, which reflects more advanced changes within the joint.

Stiffness is another hallmark symptom, often most noticeable first thing in the morning or after sitting for an extended period. In classic knee osteoarthritis, this stiffness tends to ease within a relatively short time after starting to move again, which is a helpful distinguishing feature compared to some other joint conditions where morning stiffness lasts much longer.

Swelling around the knee can occur as well, sometimes related to mild inflammation within the joint. Many people also notice a grinding, clicking, or crackling sensation with movement, known as crepitus, along with a gradual reduction in range of motion over time. Functionally, these symptoms often show up first as difficulty with activities like climbing stairs, kneeling, or standing for extended periods, since these movements place particular demand on the knee joint.

How Is Osteoarthritis Diagnosed?

Osteoarthritis is typically diagnosed through a combination of a person's reported symptoms, a physical examination, and, when needed, imaging of the affected joint. In many cases, a careful history and physical exam alone can identify a pattern consistent with osteoarthritis without requiring extensive testing right away.

During a physical examination, a healthcare provider often checks for tenderness around the joint, any grinding or crackling sensation with movement, swelling, and the joint's overall range of motion. These findings, combined with the pattern and timing of someone's symptoms, help build a clearer picture of what's happening.

When imaging is used, a standard X-ray is generally the first choice, since it can show narrowed joint space and other bone changes consistent with cartilage loss. More advanced imaging is typically reserved for situations where the diagnosis is unclear or when another condition needs to be ruled out. Because imaging findings don't always match up precisely with how much pain or difficulty someone is experiencing, symptoms and functional impact are considered just as important as what imaging alone shows when it comes to understanding the full picture.

How Can I Support My Joint Health Day to Day?

Maintaining a healthy body weight is one of the most impactful everyday habits for supporting joint health, particularly for weight-bearing joints like the knee, since every pound of excess weight translates into meaningfully more force placed on the knee with each step. Even modest, sustainable changes in this area can make a noticeable difference in comfort over time.

Staying appropriately active, even when a joint is uncomfortable, generally supports better joint health than prolonged rest, since movement helps maintain strength in the muscles that support and stabilize a joint. Low-impact activities are often more comfortable for joints already experiencing some degree of osteoarthritis compared to high-impact options, though the right level of activity varies from person to person.

Protecting joints from unnecessary repetitive stress, being mindful of body mechanics during activities like lifting, and allowing adequate rest between periods of more demanding physical activity all support long-term joint health as well. Paying attention to how a joint responds to different activities, and adjusting accordingly rather than pushing through significant pain, is a valuable habit for understanding your own body's specific patterns and limits over time.