Delaying Knee Surgery With Synvisc

Synvisc (hylan G-F 20) is a viscous fluid derived from a substance known as hyaluronan (sodium hyaluronate). Hyaluronan is produced naturally in the body to helps lubricate the joints. The form found in Synvisc is made from gelatinous substances derived from chicken combs.

Synvisc is used in a form of therapy known as viscosupplementation in which the substance is injected into joint spaces to help increase lubrication.

Man wearing knee brace, cropped
PhotoAlto / Odilon Dimier / Brand X Pictures / Getty Images 

Drug Overview

Synvisc injections are approved for the treatment of osteoarthritis of the knee in people who have failed to respond to more conservative therapy, including analgesics and non-drug options.

Synvisc is delivered in a 2-milliliter injection directly into the knee joint. It has not yet been approved for any joint other than the knee. Synvisc is typically given as a series of three injections delivered weekly or every-other-week. To achieve the best results, synovial fluids in the cavity of the knee are typically removed before the first injection.

There is another Synvisc product, known as Synvisc-One, which is administered as a single, 6-milliliter shot.

Synvisc was approved for use by the U.S. Food and Drug Administration on August 8, 1997. Synvisc-One received its FDA approval on February 26, 2009.

Side Effects

The most common side effects associated with Synvisc include:

  • Pain, swelling, or stiffness in the injected knee
  • Joint effusion ("water in the knee")
  • Joint nerve pain
  • Rash or hives
  • Fever
  • Nausea
  • Headache
  • Dizziness
  • Muscle cramps
  • Fatigue

Most of these symptoms are mild to moderate in severity and will resolve on their own without treatment. If any of the symptoms persist or worsen, call your healthcare provider immediately as this may be a sign of an infection or allergy.

The Effectiveness of Synvisc in Delaying Knee Surgery

Several studies have been done to assess whether hyaluronic acid injections are successful in delaying knee replacement surgery. One study using a database of 182,022 patients who received a total knee replacement (TKR) surgery found that the injections were associated with delaying the need for the surgery. Those who did not get the injections had the surgery within 0.7 years, those with one course of injections had the surgery in 1.4 years, while those with five courses of treatment delayed the surgery by 3.6 years. Similar results have been found in other large follow-up studies.

However, the American Academy of Orthopaedic Surgeons notes that research has not generally found that viscosupplementation is effective in reducing pain or improving function. Whether you find relief or not is highly variable, although it might be enough to help you delay a total knee replacement.

Osteoarthritis of the knee is today the most common type of arthritis in the United States, affecting an estimated 13.7 million people. Based on the study findings, Synvisc is considered to be a safe and effective means of treating pain and disability in this population and, when used appropriately, may help delay surgery for three years or more.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Cleveland Clinic. Viscosupplementation for osteoarthritis of the knee.

  2. Cleveland Clinic. Hylan G-F 20 intra-articular injection.

  3. U.S. Food and Drug Administration. Summary of Safety and Effectiveness Data Synvisc-One.

  4. Altman R, Lim S, Steen RG, Dasa V. Hyaluronic acid injections are associated with delay of total knee replacement surgery in patients with knee osteoarthritis: Evidence from a large U.S. Health claims database [published correction appears in PLoS One. 2016;11(1):e0148591]. PLoS One. 2015;10(12):e0145776. doi:10.1371/journal.pone.0145776

  5. American Academy of Orthopaedic Surgeons. Viscosupplementation for knee arthritis.