Arthritis is the leading cause of knee pain. Here we will discuss the effects of arthritis on your knees. How it occurs. How it might be prevented. The symptoms and how they may be treated. Historically, arthritis has been one of the most prevalent factors in hindering the way the knee is supposed to function. More times than not, arthritis is a result of degeneration of the cartilage in the knee. It happens slowly, over time and the pain associated with it develops just as gradually. Normally, the knee joint will become swollen, sore and stiff and over time can lose its full range of motion.