The progression of established osteoarthritis can be slowed considerably with a number of conservative measures, but it cannot be reversed. Ultimately, the knee joint surface in the active individual can be worn down to the point where the bone surfaces are grinding against each other. On x-ray this is seen as the well known”bone-on-bone” appearance. Since the sensitive nerve endings are located on the exposed surface of the bone, the knee is painful, especially with weight bearing. At this point, viscosupplementation and NSAID’s no longer are effective.
Knee replacement of any kind is a major operation. With this procedure there is potential for moderate to severe pain. The long term success of a knee replacement requires early range of motion, which is difficult if the knee hurts a lot. It is important for the surgeon to develop a pain management plan that prevents severe episodes of pain, while avoiding the strong side effects of nausea, dizziness, hypotension, and lethargy. The standard approach is the use of a general or spinal anesthesia followed by intravenous narcotics (PCA) for pain control.
When conservative measures have failed or conditions exist that make conservative measures likely to fail, operative treatment can offer a solution.
Arthroscopic surgery, or Arthroscopy, is an outpatient surgical procedure usually done under a general anesthetic. Three small incisions are made around the knee. Through these incisions a small telescope (arthroscope) is placed to view all aspects within the joint. A high definition miniature television camera is used to project the image on a plasma screen. This allows the surgeon to see into the joint with an incredible amount of clarity. Small instruments can be used to perform a variety of procedures in the knee joint. 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.