What is Hyalgan?
Hyalgan injections are not steroid injections. Hyalgan is an injectable solution of a substance called hyaluronic acid. It can be injected into joints that contain synovial fluid, such as the knee, and they can help people who have pain and stiffness due to osteoarthritis.
Almost everyone over the age of 60 has osteoarthritis to a greater or lesser degree, although not everyone is bothered by symptoms. Osteoarthritis of the knee or hip may occur in younger people, sometimes due to excessive sports, particular jobs involving a lot of lifting or kneeling, too much bodyweight, or abnormal joint development.
Osteoarthritis occurs in particular joints of the body called “synovial joints”. A synovial joint is one in which the ends of the bones are covered by very smooth cartilage, and enclosed in a tough capsule. In between the two cartilage surfaces there is a thick, viscous liquid called synovial fluid. This fluid has four important functions:
1. It keeps the cartilage surfaces of the joint very slightly apart, protecting them from wear and tear.
2. It acts like a shock absorber, again protecting the cartilage.
3. It provides lubrication to the joint.
4. It filters out harmful cells and substances, whilst at the same time allowing nutrients to reach and nourish the joint cartilage.
Synovial fluid contains a substance called hyaluronic acid, and this is what allows the synovial fluid to perform all of its functions at the same time. The hyaluronic acid in synovial fluid does not stay there for a whole lifetime, but is continuously broken down and replaced. Normally, there is a balance between the breakdown of old hyaluronic acid and the production of new hyaluronic acid, but in osteoarthritis this balance is disturbed for some reason, and breakdown occurs faster than production. As a result, the synovial fluid becomes more watery and stops working properly.
It is thought that this is one of the reasons that causes the cartilage in joints to gradually wear away. In severe circumstances, the cartilage may eventually disappear altogether, causing the bone underneath to be exposed. The thinning of the synovial fluid and wearing away of the cartilage lead to the symptoms of osteoarthritis, which includes pain, stiffness and swelling.
Injections with Hyalgan
There are a number of different preparations of hyaluronic acid that are used for joint injections. Hyaluronic acid injections have been given to thousands of patients and have not been found to cause any serious side effects, other than slight discomfort and soreness for a while after the injection.
Treatment of arthritic joints with Hyalgan injections involves a series of three injections, given at weekly intervals. This can be repeated annually if necessary.