There is much controversy as to how to treat knee pain nonoperatively, and if cortisone injections are dangerous in the knee. The type of cortisone used, dose, number of injections and frequency of injections, as well as side effects are all controversial topics among orthopaedic surgeons.
The knee, being one of the largest joints in the body, is susceptible to the development of conditions that cause pain and swellng, like osteoarthritis, trauma and rheumatoid arthritis. Osteoarthritis is the most common of these conditions, representing 15% of most people over the age of 60 in developed countries. Symptomatic knee osteoarthritis has been found prevalent more commonly in women than men.
Initially, we treat early osteoarthritis of the knee with physical therapy, weight reduction, anti inflammatory medications like Advil and Aleve, and eventually move to prescription anti inflammatory medications, pain killers, braces, knee injections and sometimes surgery.
Cortisone has been one of the most common injections used in the knee for decades and benefits patients by relieving both pain and inflammation for weeks to months.
Cortisone has been demonstrated in some studies to reduce the deterioration of knees and the development of more severe osteoarthritis, but concern has been raised about the potential side effects of long-term corticosteroid injection. There is evidence to suggest that frequent doses of cortisone may degrade joint cartilage and change the properties of meniscal cartilage by altering the cartilage cells. There are also numerous scientific studies demonstrating direct toxic effects of cortisone on joint structures including ligaments.
So how often is it safe to inject cortisone into the painful knee of someone with moderate osteoarthritis who is not yet ready for joint replacement surgery?
According to a study by Zuber in 2002, cortisone can be injected into a knee every 6 weeks with no more than 2 to 3 injections per year. There is no solid evidence to suggest repeat injections of cortisone lead to joint destruction and the 3 injections/year guideline is simply that–a guideline.(Zuber TJ. Knee joint aspiration and injection. Am Fam Physician 2002; 66: 1497–501).
In 1967, Salter, Gross and Hall concluded that:
“While it is unlikely that a single intra-articular injection of hydrocortisone is harmful, multiple intra-articular injections of hydrocortisone in a given joint are probably deleterious to the articular cartilage and should be avoided in order to prevent the iatrogenic complication of hydrocortisone arthropathy.” (Salter RB, Gross A, Hall JH. Hydrocortisone arthropathy: an experimental investigation. Can Med Assoc J 1967; 97: 374–7.)
This advice is still relevant today in spite of 45 additional years of research.
Personally, I concur with the author of today’s source article in Medscape who suggests cortisone injections are effective in patients who are not yet ready for knee replacement, who are on a waiting list for knee replacement, in young patients who knee replacement is to be avoided until later life if possible, and in patients who have medical or other reasons they cannot undergo knee replacement. I administer these injections 6 weeks apart for a total of 3, if required–and wait 6 months between treatment courses before repeating if necessary. Some point along the line, the decision would be made whether to proceed with joint resurfacing or replacement based on the patient factors such as age and medical status, as well as disease factors such as severity and functional abilities.
For more information on Cortisone, please visit: http://en.wikipedia.org/wiki/Cortisone