Synvisc-One Knee Injections

Sanofi Genzyme’s Synvisc-One injections supplement natural synovial fluid in the knee. The gel cushions bones and relieves osteoarthritis pain. In 2017, the company discovered bacterial contamination and recalled 18,000 syringes.

Synvisc-One Box
Synvisc-One Facts
  1. Manufacturer Sanofi Genzyme
  2. Active Ingredient Hylan A and hylan B polymers
  3. Dosage 16 ml (three doses per syringe)
  4. Mechanism of Action Supplements synovial fluid to cushion the knee and relieve pain of osteoarthritis of the knee
  5. Drugs in this class GelSyn-3, Gel-ONE, Hyalgan, Supartz, Durolane, Orthovisc, Euflexxa, GenVisc 850, Visco-3, Orthovisc, Monovisc, Hymovis
  6. FDA Approval February 2009

Synvisc-One is a gel made from a natural chemical. It is harvested from chicken combs – the fleshy crest on the birds’ heads. The arthritis treatment mimics the cushioning properties of synovial fluid in the knee.

Synvisc-One is intended for people with severe osteoarthritis knee pain – but only after diet, exercise and over-the-counter pain remedies do not provide relief. The gel is pre-packaged in syringes for use. A doctor performs the injections, which can provide pain relief for up to six months.

Genzyme is a U.S.-based subsidiary of French drug manufacturer Sanofi SA. In December 2017, it recalled 18,000 syringes of Synvisc-One. More than 12,000 syringes had already been distributed in the U.S.

All of the recalled syringes came from a single lot: 7RSL021. Patients who suffered complications after contaminated Synvisc-One knee injections are suing the manufacturer.

What Is Synvisc-One Knee Injection?

Synvisc-One is one of several treatment options for osteoarthritis (OA) of the knee.

OA is the most common cause of pain and disability in the joint. Knee osteoarthritis can result from trauma or from wear and tear on the joint. It’s estimated that more than one in 10 Americans older than 25 have signs or symptoms of the condition.

Symptoms of Knee Osteoarthritis
  • Inflammation
  • Joint pain
  • Limited motion
  • Morning stiffness
  • Night pain
  • Noises from the knee

How Synvisc-One Knee Injections Work

Did you know?
A single Synvisc-One knee injection may provide pain relief for up to six months.

Doctors inject Synvisc-One directly into the knee. It’s made from hyaluronic acid (HA), the same chemical found in synovial fluid in the knee. The gel lubricates the knee and works as a shock-absorber.

Genzyme introduced its original Synvisc in 1997. The original drug required weekly injections for up to three consecutive weeks.

The U.S. Food and Drug Administration approved the newer Synvisc-One in 2009. It allows for a single injection that may provide pain relief for up to six months.

Treating Arthritis Pain with Synvisc-One

Synvisc-One is part of a class of drugs called hyaluronic acid derivatives (HADs). The FDA has approved these drugs to treat arthritis knee pain when other methods don’t work.

The FDA says that patients should use hyaluronic acid derivatives only after trying alternatives.

Pain relief treatments for knee osteoarthritis:
  • Diet and exercise
  • Physical and occupational therapy
  • Acetaminophen (Tylenol)
  • NSAIDS (Aspirin, Advil, Aleve, Motrin)
  • Steroid injections

American College of Rheumatology guidelines call for treating mildly symptomatic knee arthritis with diet and exercise. The guidelines suggest over-the-counter or certain prescription pain relievers for initial pain management.

In 2012, the American Academy of Orthopaedic Surgeons published new guidelines for treating osteoarthritis in the knee. It did not recommend using HADs for patients merely showing arthritis symptoms.

Synvisc-One Knee Injection Recall

In December 2017, Sanofi Genzyme discovered bacterial contamination in some Synvisc-One syringes. The company recalled a single lot of the arthritis treatment.

The lot contained 18,000 syringes, including 12,380 already distributed. All of the affected syringes where shipped to the U.S. market.

Recalled Synvisc-One Syringes
  • Lot Number: 7RSL021
  • Expiration Date: May 31, 2020
  • Distributed Between: Oct. 25, 2017 through Nov. 7, 2017

Reasons for Synvisc-One Recall: Contamination, Infection Risk

Sanofi Genzyme said that it was investigating the “presence of microbial contamination.”

Days later, the company ordered the Synvisc-One recall. The recall notice told doctors to be “aware of the potential of a gram-negative infection.”

Gram-negative bacteria include E. coli, Salmonella and other hard to treat bacteria. Many have developed antibiotic resistance. They can lead to serious complications including pneumonia and bloodstream infections.

Synvic-One Knee Injection Side Effects

The Boston Globe reported that the recalled lot of Synvisc-One was associated with “an unexpected surge in ‘adverse events.’”

The FDA received reports from people experiencing severe pain and other complications following Synvisc-One treatments.

Reports show that patients had to have excess fluid drained from their knees.

At least one patient’s lab test showed an elevated white blood cell count (WBC). A high WBC is a sign the body is fighting off an infection.

Please seek the advice of a medical professional before making health care decisions.

Related Pages
Terry Turner
Written By Terry Turner Writer

Terry Turner has been writing articles and producing news broadcasts for more than 25 years. He covers FDA policy, proton pump inhibitors, and medical devices such as hernia mesh, IVC filters, and hip and knee implants. An Emmy-winning journalist, he has reported on health and medical policy issues before Congress, the FDA and other federal agencies. Some of his qualifications include:

  • American Medical Writers Association (AMWA) and The Alliance of Professional Health Advocates member
  • Centers for Disease Control and Prevention Health Literacy certificates
  • Original works published or cited in Washington Examiner, MedPage Today and The New York Times
  • Appeared as an expert panelist on hernia mesh lawsuits on the BBC
Edited By
Medically Reviewed By
Dr. Aimee V. Hachigian-Gould
Dr. Aimee V. Hachigian-Gould Orthopedic Surgeon

16 Cited Research Articles

  1. McGrath, A.F. (2013, October 11). A Comparison of Intra-Articular Hyaluronic Acid Competitors in the Treatment of Mild to Moderate Knee Osteoarthritis. Journal of Arthritis. Retrieved from
  2. Arthritis Foundation. (2017, December 12). Synvisc-One Injections Recalled. Retrieved from
  3. Palmer, E. (2017, December 12). Sanofi Recalls Arthritis Injection That is tied to Microbial Contamination. FiercePharma. Retrieved from
  4. Saltzman, J. (2017, December 12). Sanofi Genzyme Issues Recall for Contaminated Arthritis Gel. Boston Globe. Retrieved from
  5. American Academy of Orthopaedic Surgeons. (2013, May 18). Treatment of Osteoarthritis of the Knee; Evidence-Based Guideline 2nd Edition.
  6. Hochberg, M.C., et al. (2012, April). American College of Rheumatology 2012 Recommendations for Use of Nonpharmacological and Pharmacologic Therapies in Osteoarthritis of the Hand, Hip, and Knee. Arthritis Care & Research. Retrieved from
  7. CVS Caremark. (n.d.). Hyaluronic Acid Derivative FEP Clinical Rationale. Retrieved from
  8. U.S. Centers for Disease Control and Prevention. (2011, January 17). Gram-Negative Bacteria Infections in Healthcare Settings. Retrieved from
  9. Sanofi Genzyme. (2009, February 26). FDA Approves Genzyme’s Synvisc-One for Osteoarthritis of the Knee. Retrieved from
  10. Sanofi Biosurgery. (n.d.). Synvisc-One; A Different Way to Treat. Retrieved from
  11. Sanofi. (2017, December 19). Voluntary Recall of Synvisc-One Lot 7RSL021. Retrieved from
  12. Palo Alto Medical Foundation. (n.d.). Treatment Options for Osteoarthritis in the Knee. Sutter Health. Retrieved from
  13. National Institutes of Health. (2016, March 8). Gram-Negative Bacteria. National Institute of Allergy and Infectious Diseases. Retrieved from
  14. Mayo Clinic. (2018, January 11). High White Blood Cell Count. Retrieved from
  15. U.S. Food and Drug Administration. (2018, December 20). MAUDE Adverse Event Report. Retrieved from
  16. U.S. Food and Drug Administration. (2018, January 19). MAUDE Adverse Event Report. Retrieved from
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