Synvisc-One for Knee Osteoarthritis: Complete Patient Guide

Key Takeaways

• Single-shot convenience: One injection provides relief for up to 6 months
• Medicare-covered: Most insurance plans cover Synvisc-One when medically necessary
• Proven track record: Over 20 years of clinical research supporting safety and effectiveness
• Allergy consideration: Not suitable if you have bird or egg allergies
• Cost-effective: Typically $100-$300 with insurance, $800-$1,200 without

What Is Synvisc-One?

Synvisc-One is a gel injection (also called viscosupplementation) designed to relieve knee pain from osteoarthritis. It works by restoring the natural cushioning fluid in your knee joint that arthritis wears away over time.

Unlike cortisone shots that reduce inflammation temporarily, Synvisc-One supplements the synovial fluid in your joint - think of it as adding lubricant to a squeaky hinge. The “One” in the name refers to its key advantage: you only need one injection instead of the three-shot series required by some other gel injection products.

Manufactured by Sanofi, Synvisc-One has been FDA-approved since 2009 and is one of the most commonly prescribed viscosupplementation products in the United States.

Quick Facts

Is Synvisc-One Right for You?

Best For:

• Adults with mild to moderate knee osteoarthritis
• Patients who want to avoid or delay knee surgery
• Those who haven’t found adequate relief from physical therapy, exercise, or pain medications
• People seeking longer-lasting relief than cortisone shots provide
• Anyone who prefers a single injection over multiple visits
• Patients with Medicare or private insurance (usually covered)

Consider Alternatives If:

• You have an allergy to birds or eggs (see warning below)
• You have severe “bone-on-bone” arthritis (may need surgery instead)
• You have an active knee infection or skin disease around the injection site
• You’re allergic to hyaluronic acid or previous gel injections
• You prefer non-avian options (Euflexxa, Monovisc, Gelsyn-3 use bacterial sources)

How Synvisc-One Works

Your knee joint naturally contains synovial fluid - a thick, gel-like substance that cushions your bones and helps them glide smoothly during movement. In healthy knees, this fluid contains high levels of hyaluronic acid (HA), which gives it its protective properties.

When osteoarthritis develops, the synovial fluid becomes thinner and less effective. Bone rubs against bone more, causing pain, stiffness, and inflammation.

Synvisc-One replaces what arthritis takes away. Here’s how:

1. Restoration: The injection adds hyaluronic acid back into your joint space
2. Cushioning: The thick gel provides immediate padding between your bones
3. Lubrication: Your joint moves more smoothly with less friction
4. Protection: The HA may help protect remaining cartilage from further damage

The hylan G-F 20 formula in Synvisc-One is “cross-linked,” meaning the molecules are chemically connected to create a thicker, longer-lasting gel than some other products. This is why one injection can provide relief for months.

What to Expect During Treatment

Before Your Injection

• Your doctor will review your medical history and confirm you’re a good candidate
• You’ll be asked about bird/egg allergies specifically
• An X-ray or physical exam will confirm your arthritis diagnosis
• Some doctors may remove excess fluid from your knee first (called aspiration)

During the Procedure

The injection takes about 5-10 minutes:

1. Positioning: You’ll sit or lie down with your knee relaxed and slightly bent
2. Cleaning: The injection site is thoroughly cleaned with antiseptic
3. Numbing (optional): Some doctors apply a local anesthetic or numbing spray
4. Injection: Your doctor inserts a needle into your joint space and slowly injects the gel
5. Bandage: A small bandage is applied to the injection site

Will it hurt? Most patients describe mild discomfort or pressure during the injection - similar to a flu shot. The numbing medication helps significantly.

Imaging guidance: Some clinics use ultrasound or fluoroscopy (real-time X-ray) to ensure precise needle placement. Research shows this improves accuracy and may improve outcomes, though not all providers offer it.

After the Injection

• First 48 hours: Avoid strenuous activity, prolonged standing, or high-impact exercise
• Activity restrictions: No jogging, heavy lifting, or standing for long periods for 2 days
• Ice if needed: Apply ice for 10 minutes at a time if you have mild swelling
• Normal movement: Gentle walking and daily activities are encouraged
• Follow-up: Most doctors schedule a check-in 2-4 weeks later

Some patients feel relief within a few days, while others may take 2-4 weeks to notice improvement.

Effectiveness & Duration of Relief

Clinical Evidence

Multiple studies have evaluated Synvisc-One’s effectiveness:

• Pain reduction: Clinical trials show 30-50% reduction in pain scores for many patients
• Duration: Relief typically lasts 3-6 months on average
• Functional improvement: Patients report better ability to walk, climb stairs, and perform daily activities
• Surgery delay: Some research suggests viscosupplementation may delay knee replacement by 2-3 years for suitable candidates

Important context: Results vary widely. Some patients experience dramatic relief lasting 6+ months, while others see minimal benefit. Factors that influence success include:

• Severity of arthritis (works best for mild-moderate cases)
• Injection accuracy (imaging-guided injections may improve outcomes)
• Individual biology and activity level
• Overall joint health

How Long Does It Last?

Most patients experience peak relief around 4-12 weeks after injection, with effects gradually wearing off over 3-6 months. When pain returns, you can repeat the injection - Medicare and most insurers allow Synvisc-One every 6 months.

Side Effects & Safety

Common Side Effects (10-20% of patients)

• Temporary pain or swelling at the injection site (usually resolves in 2-3 days)
• Joint stiffness for 24-48 hours after injection
• Warmth or redness around the knee
• Mild bruising where the needle entered

These reactions are usually mild and can be managed with ice and over-the-counter pain relievers.

Less Common Side Effects (1-5% of patients)

• Pseudoseptic reaction: Temporary inflammatory flare that mimics infection (painful swelling, warmth, fluid buildup)
  • Usually occurs 24-72 hours after injection
  • Resolves on its own within a few days
  • Not a true infection, but your doctor may drain fluid to rule one out
• Allergic reaction: Rash, itching, or hives (see allergy warning below)
• Headache or muscle pain

Rare But Serious Complications

• Infection: True joint infections are rare (less than 1 in 10,000) but require immediate treatment
• Severe allergic reaction: Anaphylaxis is extremely rare but requires emergency care

When to Call Your Doctor

Contact your healthcare provider if you experience:

• Severe pain that worsens after 3 days
• Fever or chills
• Significant knee swelling that doesn’t improve with ice
• Signs of allergic reaction (difficulty breathing, severe rash, facial swelling)

Important Allergy Warning

Synvisc-One is derived from chicken combs and is NOT safe if you have allergies to birds or eggs.

The hyaluronic acid in Synvisc-One comes from avian (bird) sources. If you have a known allergy to:

• Birds (chickens, turkeys, etc.)
• Eggs or egg products
• Feathers or down

You should NOT receive Synvisc-One. Allergic reactions can range from mild (rash, itching) to severe (anaphylaxis).

Alternatives for Patients with Bird/Egg Allergies

If you have these allergies, ask your doctor about non-avian options:

• Euflexxa (bacterial-derived, three injections)
• Monovisc (bacterial-derived, single injection)
• Gelsyn-3 (bacterial-derived, three injections)

These products use hyaluronic acid produced through bacterial fermentation, not animal sources.

Insurance & Cost

Medicare Coverage

Yes, Medicare Part B covers Synvisc-One when:

• You have a documented diagnosis of knee osteoarthritis (confirmed by X-ray or exam)
• Conservative treatments have failed (pain medications, physical therapy, exercise for at least 6 weeks)
• Your doctor determines it’s medically necessary

Medicare typically pays 80% after you meet your Part B deductible. You’re responsible for the remaining 20% copay.

Average Medicare patient cost: $100-$250 per injection

Private Insurance

Most commercial insurance plans cover viscosupplementation, though requirements vary:

• Some require pre-authorization
• Many require documentation of failed conservative treatment first
• Copays typically range from $50-$300 depending on your plan

Check with your insurance before scheduling to understand your out-of-pocket costs and any prior authorization requirements.

Self-Pay Costs

Without insurance, Synvisc-One typically costs:

• Injection product alone: $600-$900
• Including doctor’s office visit and injection fee: $800-$1,200 total

Some clinics offer payment plans or cash-pay discounts. Always ask about total costs upfront.

Cost Comparison

Single-shot products save time and reduce the number of office visits, which can lower total costs when you factor in copays and time off work.

Synvisc-One vs. Alternatives

Single-Shot Competitors

Bottom line: If you have bird/egg allergies, choose Monovisc. Otherwise, all three single-shot options show similar effectiveness in clinical studies.

Multi-Shot Options

Why choose multi-shot? Some insurance plans only cover the three-injection series, or some doctors believe spreading the dose over 3 weeks reduces side effects.

Synvisc-One vs. Cortisone Shots

Many patients use both: Cortisone for quick relief during flares, Synvisc-One for longer-term management.

Frequently Asked Questions

How soon will I feel relief after Synvisc-One?

Most patients notice improvement within 2-4 weeks, though some feel better within days. Peak relief typically occurs around 4-8 weeks after injection. If you don’t notice any improvement after 6-8 weeks, it may not be effective for you, and your doctor can discuss alternative treatments.

Can I get Synvisc-One in both knees at the same time?

Yes, but many doctors prefer to inject one knee at a time to reduce the risk of side effects and allow you to keep one “good” leg for mobility. If both knees are injected simultaneously, you may have temporary difficulty walking. Discuss your preference with your doctor.

How many times can I get Synvisc-One injections?

There’s no absolute limit. Many patients receive Synvisc-One every 6 months for years. Medicare allows coverage every 6 months when medically necessary. However, if the treatment stops working or your arthritis progresses to severe “bone-on-bone” stage, your doctor may recommend alternative treatments or surgery.

Does the injection hurt?

Most patients describe mild to moderate discomfort during the injection - similar to other shots. The procedure is quick (5-10 minutes), and many doctors use a numbing spray or local anesthetic to minimize pain. Some temporary soreness or stiffness for 1-2 days afterward is common.

What if Synvisc-One doesn’t work for me?

Not everyone responds to viscosupplementation. If you don’t experience meaningful relief after 6-8 weeks, talk to your doctor about:

• Alternative gel injection brands (different formulations may work better)
• Physical therapy or exercise programs
• Different medications
• Regenerative treatments (PRP, stem cells - though evidence is limited)
• Surgical options if conservative treatments have failed

Can I exercise after getting Synvisc-One?

Avoid strenuous activity for 48 hours after injection. After that, gradually return to normal activities as tolerated. In fact, regular low-impact exercise (walking, swimming, cycling) is encouraged and may help maintain the benefits of the injection.

Next Steps

If you’re considering Synvisc-One for knee osteoarthritis:

1. Confirm your diagnosis: Make sure you have documented knee OA (X-ray or physical exam)
2. Try conservative treatment first: Most insurance requires 6+ weeks of physical therapy, exercise, or medications before covering injections
3. Check for allergies: Review your medical history for bird or egg allergies
4. Verify insurance coverage: Call your insurance to understand costs and pre-authorization requirements
5. Find an experienced provider: Ask if they use imaging guidance (ultrasound or fluoroscopy) for more accurate injection placement
6. Schedule a consultation: Discuss whether Synvisc-One is the best option for your specific situation

Medical Disclaimer

This article provides general information about Synvisc-One and is not a substitute for professional medical advice. Always consult your healthcare provider about your specific condition and treatment options. Synvisc-One may not be appropriate for everyone, and individual results vary.

Last medically reviewed: January 2025