In a worst-case scenario, a joint affected by OA can become stiff and painful. These symptoms result from the loss of the smooth, gliding surface that undamaged cartilage provides. As the disease progresses, the cartilage in a joint becomes thin and ragged, and more stiffness and a “catching” sensation may occur. These problems may cause a person to restrict the motion of that joint, which can in turn cause the surrounding ligaments to contract and tighten. The muscles that move the joint may ultimately become weakened and thin, with the overall effect being a loss of mobility and a disruption of work and recreation. This is a dire prediction, but not an unavoidable one: It reflects a scenario where the person with OA receives no medical care.
In reality, the prognosis for OA is generally very good. Many people ask, “Isn't rheumatoid arthritis the crippling arthritis—the type of arthritis that leads to disability?” This question suggests that the prognosis for rheumatoid arthritis (RA) is bad, and the prognosis for all other types of arthritis is much better. This is an oversimplification. It is possible to have a mild case of RA or a severe case of OA. Moreover, many factors affecting the final outcome of arthritis depend on the person seeking treatment. Specifically, is the individual compliant with that treatment prescribed, is he or she receiving timely medical care, and does the individual work to maintain a healthy lifestyle?
The prognosis for osteoarthritis is generally very good.
It is difficult to predict the outcome of OA based on a history and physical exam. One person may have a relatively mild course of OA affecting a few joints; another may develop severe disease in many joints that render him or her unable to work. Some new studies suggest that “active synovitis” or inflammation of the cartilage seen on magnetic resonance imaging (MRI) or bone scan suggests a more aggressive and debilitating course of disease, although the results of these studies are still being debated. Some risk factors suggestive of a more disabling course of OA are believed to include obesity, early age of disease onset, sedentary lifestyle, traumatic joint injuries, and joint x-rays that show very little joint space or “bone-on-bone” contact between the bones of the joint.
Predicting the severity of anyone's OA is difficult. Nevertheless, identifying risk factors for progression of disease gives doctors and patients an opportunity to improve those risks that can be modified.