Synvisc-One Knee Injection Complications

Sanofi Genzyme recalled 18,000 Synvisc-One knee injection syringes after discovering bacterial contamination. Patients injected with the recalled gel reported serious complications that required medical treatment.

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  • Sanofi Genzyme recalled 18,000 syringes of Synvisc-One arthritis gel in late 2017.
  • The recall followed what the company called “an unexpected surge” in reported complications.
  • Sanofi Genzyme’s investigation warned bacteria in recalled syringes “could result in infection.”

Sanofi Genzyme saw a spike in reported complications from Synvisc-One knee injections in late 2017. The reports often mirrored common side effects of the arthritis gel. But the number of reports was higher than expected. And the reported complications were often more severe.

Sanofi Genzyme recalled 18,000 Synvisc-One syringes in December 2017.

When it sent out its recall notice, the company warned that the affected lot “may result in the risk of infection.”

Sanofi Genzyme identified the contamination as gram-negative bacteria. But the company did not specify the exact type.

Synvisc-One Knee Injections

Sanofi Genzyme’s Synvisc-One is an injectable arthritis treatment for the knee.

The gel is part of a class of drugs called hyaluronic acid derivatives.

Arthritis can deplete natural synovial fluid that cushions the knee joint. Synvisc-One supplements this fluid.

Contaminated Synvisc-One Complications

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Several people experienced severe pain and swelling after Synvisc-One arthritis treatments. Doctors and patients reported complications to the U.S. Food and Drug Administration.

One report said a patient was unstable after an injection. The patient’s knee was unable support her weight. Another patient reportedly had to spend a week in bed after an injection.

Some patients required multiple outpatient treatments to drain fluid from their knees. Others required emergency room visits or hospitalization.

Patients who experienced complications after contaminated Synvisc-One knee injections are filing lawsuits against the manufacturer.

Complications May Mirror Common Synvisc-One Side Effects

Seven percent of patients injected with Synvisc-One normally report some type of mild side effect.

Common Synvisc-One Side Effects:

  • Fluid buildup in or around the knee
  • Heat
  • Pain
  • Redness
  • Swelling

The side effects from the contaminated lot mimicked typical complications. But in some cases, patients reported the common side effects carried amplified complications.

Complications, Contamination Cause Synvisc-One Recall

Magnification of the E. Coli bacteria
E. coli is a type of gram-negative bacteria.

Sanofi Genzyme told health care providers not to use a specific lot of Synvisc-One until the company investigated for possible contamination.

Sanofi Genzyme investigated and discovered hard-to-treat gram-negative bacteria contaminating some syringes. This is a type of bacteria that includes E. coli and Salmonella.

On Dec. 11, 2017, the company recalled 18,000 units of the gel. By that time, the company had already distributed more than 12,000 syringes.

What Is Gram-Negative Bacteria?

The most familiar gram-negative bacteria are E. coli and Salmonella. But, the group includes several other difficult-to-treat bacteria. This type of bacteria can cause pneumonia, bloodstream, wound and surgical site infections.

Gram-negative bacteria are resistant to many drug treatments. This group of bacteria has also become increasingly resistant to antibiotics. This can force health care providers to rely on older drugs for treatment. But older drugs, such as colistin, may have toxic side effects.

Common Gram-Negative Infections

Bacteria Typical Conditions It Can Cause
Acinetobacter baumanii Infections in hospital settings, wound infections
E. coli Majority of urinary tract infections
Klebsiella pneumoniae Pneumonia, urinary tract infections and bloodstream infections in hospitalized patients
Legionella Legionnaires disease, a severe form of pneumonia
Pseudomonas aeruginosa Bloodstream infections and pneumonia in hospitalized patients; common cause of pneumonia in people with cystic fibrosis
Salmonella Digestive tract infection

Hospitals have a particular concern over gram-negative bacteria. They can fuel infection outbreaks among people with weakened immune systems. Gram-negative bacteria can also pass along their genetic material. This can help other bacteria become drug resistant.

Sanofi Genzyme did not name the exact bacteria that contaminated Synvisc-One syringes.

The company manufactures the active ingredient in Synvisc-One, hyaluronic acid, from chicken combs.

Salmonella outbreaks have been associated with poultry. The CDC website points out that birds such as turkeys, ducks and chickens often carry Salmonella.

How to Tell If You Received a Recalled Synvisc-One Knee Injection

Recalled Synvisc-One injections can be identified by their lot number.

People who believe a contaminated Synvisc-One injection injured them, should contact their doctors.

The doctor who gave the injection should be able to find out if it came from the recalled lot.

Recalled Synvisc-One Injections

Lot Number: 7RSL021

Distributed Between: Oct. 25, 2017 through Nov. 7, 2017

Recalled: Dec. 11, 2017

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.

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