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.

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Synvisc-One Box

Manufacturer: Sanofi Genzyme

Active Ingredient: Hylan A and hylan B polymers

Dosage: 16 ml (three doses per syringe)

Mechanism of Action: Supplements synovial fluid to cushion the knee and relieve pain of osteoarthritis of the knee

Drugs in This Class: GelSyn-3, Gel-ONE, Hyalgan, Supartz, Durolane, Orthovisc, Euflexxa, GenVisc 850, Visco-3, Orthovisc, Monovisc, Hymovis

FDA Safety Communications: None as of February 2018

FDA Approval: February 2009

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Fast Facts

  • Sanofi Genzyme Synvisc-One supplements natural fluid in the knee to relieve osteoarthritis pain.
  • Synvisc-One’s active ingredient is harvested from chicken combs.
  • The company recalled 18,000 units of Synvisc-One after finding bacterial contamination.

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 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

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Sanofi Genzyme said 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 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.


Terry Turner is an Emmy-winning, former television journalist. He is an associate member of the American Bar Association, the ABA’s Health Law group and a member of the Alliance of Professional Health Advocates. He holds six certificates in Health Literacy for Healthcare Professionals from the Centers for Disease Control and Prevention. As a Washington-based investigative reporter, he routinely reported on health and medical policy issues before Congress, the FDA and other federal agencies. Terry received his B.A. in Media Arts from Lyon College.

Hide Sources

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