According to the Cleveland Clinic, 21 million Americans are affected by osteoarthritis, typically of the weight-bearing joints. Osteoarthritis can occur in any joint, but it's very common in the knees. Also known as degenerative joint disease, osteoarthritis develops over time, when the cartilage that lines the weight-bearing surfaces of the joints begins to break down and wear away.
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For some individuals, the wearing away of the cartilage of the knee will result in pain, stiffness and swelling. These symptoms can range from mild to debilitating. According to The Academy of The American Family Physician, knee osteoarthritis is a common, but often difficult problem to manage in primary care. One way to manage the problems caused by knee osteoarthritis is with gel injections.
Types of Gel Injections
Viscosupplementation, commonly referred to as gel injection, is an injection into the knee joint with a gel-like substance called hyaluronate, or hyaluronic acid. Hyaluronic acid is one of the naturally occurring lubricants in a healthy knee. According to the Cleveland Clinic, pharmaceutical companies in the United States have developed three main hyaluronic acid-based gels, known by the brand names Hyalgan, Synvisc and Supartz. Some of the injection gels are made from biological sources, while others are created synthetically. The technique of viscosupplementation was approved in 1997 by the U.S. Food and Drug Administration for use in the knee, according to the American Academy of Orthopaedic Surgeons.
Gel injections are performed in a physician's office. Often the physician will use a topical anesthetic to numb the skin prior to the injection. The procedure takes just a few minutes and can be given in one or both knees during the same office visit. The full course of treatment is determined by the choice of injectable. According to the Cleveland Clinic, Synvisc requires three injections, spaced one week apart, while Hyalgan and Supartz each require five injections, spaced one week apart. You will be asked to modify your activity and avoid prolonged weight-bearing activities for 48 hours following each injection.
As of 2010, there is no cure for osteoarthritis. Gel injections are meant to mimic the knee joint's own natural lubricating properties and provide temporary relief for an undetermined period of time. Results are quite variable. The Cleveland Clinic reports that of those who were helped by gel injections, most reported the greatest pain relief coming eight to 12 weeks after beginning treatment. Often, the entire series of injections will be repeated at a later date if symptoms return.
Who is a Candidate?
Gel injections are usually given after other more-conservative measures have proven ineffective. Most physicians will recommend that you first complete a course of physical therapy to increase the strength in the muscles that surround your knee. The physician may prescribe an anti-inflammatory medication or recommend an over-the-counter anti-inflammatory as part of a less-invasive approach. If exercise and medication do not control your symptoms, your physician may then recommend that you try gel injections.
The Cleveland Clinic reports that while generally safe, gel injections can result in temporary injection-site pain, swelling, heat and redness, rash and itching, bruising around the joint and fluid accumulation in the injected knee. You should be sure to tell your physician if you have any allergies to feathers, eggs or poultry, as some of the gel injections are made from these biological products.