Pain in the knee that gradually increases over time is the most common symptom of knee arthritis, according to the American Academy of Orthopaedic Surgeons, or AAOS. Difficulty extending and straightening the knee, especially after long periods of rest, is another common symptom. Arthritic knees may also make clicking or grinding noise when moved.
The AAOS defines arthritis as joint inflammation. The most common type of arthritis found in the knee is osteoarthritis. Osteoarthritis is caused by the degeneration of knee cartilage. Over time, the cartilage wears away, no longer protecting the bone. This causes bones to rub against each other.
The chance of arthritis increases with age, according to WebMD. Overweight individuals are also at risk of developing the condition because each pound adds up to 4 pounds of extra pressure on the knees. Those who work in jobs that require a lot of squatting and heavy lifting may develop osteoarthritis because of abnormal pressure on the knees. Athletes, such as soccer players and long-distance runners, may develop arthritis as well.
Although there is no cure for arthritis, many treatments are available. For example, physical therapy may reduce knee pain and improve joint function, according to Arthritis Today. Knee braces can also improve pain management and stability of the knee.