by: Kathleen A Hogan, MD
Over 30% of Americans over the age of 60 are affected by the symptoms of knee arthritis, such as pain, stiffness, swelling, and activity limitations. Initial treatments for knee arthritis include activity modification, weight loss, physical therapy, bracing, anti-inflammatory medications, and injections with steroids or hyaluronic acid (also called a gel or visco because of its consistency).
Corticosteroid injections have been used since the 1950’s to treat painful, inflamed, arthritic joints. However, they can cause temporary elevation of blood sugar in diabetics and may only give 3 months of pain relief. Even if effective in the past, repeated steroid injections may no longer provide relief. There is concern that too many steroid injections may damage normal cartilage, especially in patients with less severe arthritis. Steroid injections which are given within 3 months of a joint replacement surgery may even increase the risk of infection slightly.
Hyaluronic Acid Injections (or Viscosupplementation)
Hyaluronan is a complex molecule found in normal joint fluid which acts as a lubricant and a shock absorber. Injections of a joint with hyaluronic acid may improve the protective effects of normal joint fluid and also reduce inflammation. First approved by the FDA in 1997, there are now several different types of hyaluronic acid injections available, including Synvisc, Euflexxa, Orthovisc, and Gel One. This type of injection is also known as viscosupplementation. Most require an average of 3 injections, one week apart, although some can be given as a single injection.
What to Expect
If your physician recommends viscosupplementation for knee arthritis, it usually must be approved by your insurance carrier before it can be given. You will return to the office for the injections. The skin will be cleaned with an antiseptic such as betadine, and the skin numbed with lidocaine or a cold spray. Some physicians use ultrasound to ensure the injection is accurately placed within the joint. Excessive fluid in the knee may be aspirated and removed at the same time as the injection, which can also provide substantial pain relief.
After the Injection
After the injection, it is typically recommended that patients avoid excessive activity for 2 to 3 days. This helps to minimizes discomfort associated with the injection. Bleeding within the joint after an injection can occur in patients on aspirin, Coumadin, or other anticoagulants. It typically takes a few weeks after completing the injections to obtain maximum relief of symptoms. Pain relief should last 6 to 12 months. These injections can be repeated every 6 months.
Effectiveness of Viscosupplementation for Knee Arthritis
Viscosupplementation does not always give complete relief of pain. Studies have provided conflicting evidence on its effectiveness. A torn meniscus may be aggravating the knee joint and causing continued pain. Once arthritis becomes severe, these injections may no longer be effective. Or pain which is felt in the knee may actually be caused by arthritis elsewhere, such as the hip or spine. Not everyone is a candidate for viscosupplementation but for some patients they can provide significant relief of the pain from knee arthritis. If you are one of the million of Americans suffering from knee arthritis, there are often many treatments which can help to reduce knee pain and may help some people avoid or put off joint replacement surgery.