The most common form of arthritis, according to the American Academy of Orthopedic Surgeons is osteoarthritis. It is considered to be the garden variety wear-and-tear arthritis. One of the more frequently involved joints is that of the knee. While there are several causes of osteoarthritis, the symptoms are basically the same. The symptoms of osteoarthritis of the knee can change as the severity worsens.
Pain
The inflammatory properties of osteoarthritis are important elements in causing pain. So, too, are the mechanical properties of the disease, because as the joint deteriorates, smooth surfaces become rough and irregular, causing inflammation and swelling, which in turn causes pain.
Pain with mild osteoarthritis may be experienced as only a mild aching in the knee, which may be relieved with rest and over-the-counter anti-inflammatory drugs. As the condition worsens, there may be a need for stronger medications, and even localized treatments to the knee such as cortisone injections.
Joint Effusion
Effusion describes the abnormal buildup of excessive amounts of knee joint fluid. The greater the amount of fluid present in the knee, the more uncomfortable it can be and the more it can inhibit motion. Joint fluid, also known as synovial fluid, is a normal component in the joint, and is responsible for lubrication and nourishment of the joint cartilage.
As the amount of fluid increases, it begins to stretch the joint lining, irritating special nerve endings responsible for responding to this stretch. The result is pain.
Altered Mobility
As the joint surfaces continue to degenerate, they become increasingly rough and irregular. Large bone spurs develop along the outer joint margins in an attempt to increase joint surface to battle pain and friction. These aspects can combine to create limitations in the knee's ability to bend and straighten, thus hampering activities such as walking and stair-climbing.
Severe irregularity of the joint surfaces can ultimately lead to intense pain when under weight and an increased risk of falling.
Crepitus
Crepitus refers to the cracking, popping and grinding sensations that a severely arthritic knee will demonstrate while in motion. Crepitus can range from a mild grinding sensation to flagrant popping and a sense of the joint wanting to buckle. Crepitus occurs when two arthritis surfaces, typically without any remaining joint cartilage, rub against each other during bending or walking.
