Viscosupplementation: A Non-Surgical Treatment Option for Knee

Viscosupplementation: A Non-Surgical Treatment Option for Knee Osteoarthritis

Viscosupplementation also known as hyaluronic acid injection therapy, involves injecting a

gel-like substance called hyaluronic acid into the knee joint of people suffering from osteoarthritis. Hyaluronic acid is a natural lubricating fluid found in healthy knee joints that helps cushion the bones and allow for smooth movement. In osteoarthritic knees, the amount of hyaluronic acid decreases, resulting in less protection and cushioning of the joint surfaces. Hyaluronic acid injection therapy aims to replenish this protective fluid in order to reduce pain and improve joint function.

How Does it Work?

Hyaluronic acid injections work by supplementing the natural joint fluid that is depleted in arthritic knees. The gel-like hyaluronic acid acts as a lubricant and shock absorber in the knee joint. It provides cushioning between the bones, absorbs physical stresses, and protects the articular cartilage from damage during movement. By restoring the viscoelastic properties of synovial fluid, hyaluronic acid injections aim to improve joint lubrication, support cartilage nutrition, modify pain signal transmission, and reduce inflammatory responses in osteoarthritic knees.

What are the Different Types of Hyaluronic Acid Products?

There are several hyaluronic acid preparations available for hyaluronic acid injection therapy, which differ based on molecular weight, concentration, cross-linking, and duration of effect:

- High molecular weight hyaluronic acid: These traditional preparations aim to last 4–6 months. Examples include Supartz and Synvisc.

- Intermediate molecular weight: Durolane and Gel-One claim effects lasting 6 months.

- Low molecular weight: Hyalgan is designed to work for 3 months.

- Cross-linked hyaluronic acid: Products like Orthovisc and Euflexxa use cross-linking to increase viscosity and prolong residence time in the joint of up to 6 months.

Clinical Evidence and Effectiveness

Numerous clinical studies and meta-analyses have shown hyaluronic acid injections to be an effective treatment for reducing knee pain and stiffness associated with osteoarthritis. A 2016 Cochrane review found hyaluronic acid injection therapy to be moderately more effective for pain relief than placebo injections up to 26 weeks post-treatment. Additionally, it reported improved function when compared to placebo, corticosteroids, and standard non-surgical management. Viscosupplementation degree of effectiveness seems to depend on the specific hyaluronic acid preparation used. While all products seem to provide some benefit over placebo, some may work better than others for certain patients. In general, higher molecular weight and cross-linked versions appear to have greater efficacy and longer duration of response.

Treatment Protocol and Cost

A standard Viscosupplementation treatment course involves injecting 2–5 ml of hyaluronic acid into the knee joint through the skin in a clinician’s office. An initial injection is usually followed by 1–3 weekly or biweekly supplemental injections. Treatment response occurs gradually and pain relief may continue to improve over the first few months. Costs can range from a few hundred to over a thousand dollars per injection course, depending on the specific product used and dosage needed. While not covered by all insurance plans, costs are generally lower than surgery alternatives such as arthroscopy or joint replacement.

Potential Risks and Considerations

Overall, hyaluronic acid injections are very safe when administered properly by a trained clinician. Common mild side effects may include pain, swelling or tenderness at the injection site. Serious adverse events are rare but could include joint infection (<1%) or allergic reaction in some cases. As with any injection procedure, there is a small risk of bleeding, nerve damage or joint damage if improperly performed. Hyaluronic acid injection therapy may not provide effective relief for all osteoarthritis patients. Factors such as advanced joint damage, varus/valgus malalignment, obesity, or incomplete rehabilitation adherence could limit response. It is also not a permanent “cure” and symptoms may return after several months requiring repeat treatment courses. However, it offers a generally low-risk option for symptom relief before more invasive surgical management is considered.

Patient Candidates and Outcomes

In general, Viscosupplementation is most likely to benefit patients with mild to moderate unilateral or bilateral knee osteoarthritis who have failed to get adequate pain relief from medications, bracing, or physical therapy. It provides a minimally invasive alternative to corticosteroid injections or surgical options for these patients. Various studies have found 5070% of patients achieving good to excellent pain relief and functional improvement following a hyaluronic acid injection course, with the majority reporting satisfaction with treatment outcomes. Proper patient selection along with fulfillment of post-procedural rehabilitation protocols seems important for optimizing clinical response. Overall, for appropriate candidates, hyaluronic acid injection therapy offers a valuable non-surgical option in managing knee osteoarthritis symptoms.

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