The most common indication for arthroscopy in a knee with osteoarthritis is to remove a torn meniscus or a loose piece of joint surface (loose body).
At the same time the joint surface is examined and can be debrided (cleaned up) as necessary. In certain situations the cartilage defects can be grafted or treated with techniques such as microfracture of the bone beneath the cartilage defect, done through the scope.
The type of symptoms associated with osteoarthritis are aching pain and stiffness, often accompanied by swelling. The pain is usually predictable and increases as the day progresses. Knee arthroscopy has not been found to be useful for treatment of osteoarthritis with this pattern of pain. It is common however to have the meniscus in the knee fray and then tear causing an increase in pain and swelling. This usually presents as an exacerbation of sharp pain that comes on suddenly, and then recurs in an intermittent and unpredictable fashion. The pain occurs when the torn part of the meniscus shifts and gets stuck between the joint surfaces. The pain may be short-lived or the meniscus can become stuck and the knee may lock. In this case you cannot straighten your knee. If this is a persistent problem the meniscus tear is large enough that it will not go away by itself.
In this case, arthroscopy is recommended to remove the fragment and inspect the knee. The arthroscopy should return the knee to the way it was prior to the exacerbation. The length of time that it takes to improve depends on the severity of the arthritis.
Osteoarthritis is also known as degenerative joint disease. This is simply caused by a wearing out of the joint surface in the knee faster than the body can repair it.
Knee laxity or instability, from an injury or naturally present, may increase the stress on the knee joint because of abnormal movements that increase shear or scraping forces on the joint surface.
You have probably noticed that sometimes it seems that knee arthritis runs in families. If it does in your family, it is not due to any specific gene, but is probably related to the inherited overall alignment of your leg.
Injury to the knee at any point in your lifetime can make the knee more susceptible to arthritis. There is almost always a history of past injury when the arthritis is predominantly in one knee.
For every one pound we carry whether it is body weight or lifting, we place an additional three pounds of stress on the knee. When we climb stairs, squat, get up from a chair or out of a car we are putting 5-10 times our body weight through the knee joint.
The design of our knees allows us to participate in a tremendous number of strenuous activities. In the absence of other risk factors the knees are safely able to run ultra marathons and ironman triathlons. However, if risk factors are present, high impact activities such as running and jumping can deteriorate a knee joint at a quicker rate than low impact activities such as swimming and biking.
Recognition of your own risk factors and maintaining an active lifestyle are important ways to maintain the health of your knee. For the most part, conditioning, activity modification, and prompt careful treatment of injury are the most important steps to a long lasting knee.