Injection Options for Knee Arthritis

Approximately 30,000,000 individuals in the United States suffer from arthritis. When it comes to arthritis in the knee, the vast majority is the wear and tear variety, which is known as osteoarthritis. Non-surgical knee arthritis treatments are typically very effective and one of the best that we have has been injections into the knee.

There are two different types of knee injections that are common. The first involves injections of cortisone, which is commonly known as a steroid. These may work well for a few weeks and a few months, and then may be repeated a few times a year.

Cortisone injections are a hefty anti-inflammatory. We know that knee arthritis involves a significant amount of inflammation, because these injections tend to work very well. From that standpoint, the injections work well. but they do not alter the course of the disease. They merely work exceptionally well for pain management.

It is unclear whether steroid injections have a deleterious effect on the cartilage itself. Numerous animal studies show this to be the case, but it has not been proven in humans. So for now they remain the gold standard for nonoperative injections in an attempt to avoid surgery.

Approximately a decade ago, an injection material was developed involving hyaluronic acid. Hyaluronic acid is a significant component of native joint fluid, and acts to protect and lubricate the joint surfaces. The material developed for human injection is not made from human hyaluronic acid, rather, it's developed from rooster combs.

Injecting hyaluronic acid into a person's knee can alleviate pain and help a person's knee start to make more of the lubricating fluid. Studies performed looking at hyaluronic acid injections into the knee have shown satisfactory results, over 65% good to excellent at the one year point.

There have also been research studies comparing steroid injections to hyaluronic acid, and those have shown equivalent pain relief. Both worked well in those studies, just no different in the amount and length of pain relief.

In addition, there appear to be no difference so far in the pain relief achieved from the varieties of HA injections available on the market. There is one called Hyalgan, and another named Synvisc. Both work well, and involve typically a series of 3 to 5 injections over a period of a few weeks. Others exist as well, and there is a new one involving a one time injection of HA.

The risks of the HA injections are not significantly different from steroid injections. This involves a small risk of infection, and another risk they won't work at all in patients. One additional risk seen in HA injections is called a pseudo-infection. This is where a person's knee looks infected, but it really isn't.

Overall, HA and steroid injections work well for nonoperative pain relief. It's not clear whether steroid injections need to be used first. More research is necessary to know for certain on that.