Knee Gel Injections Explained: Benefits, Risks, and Who They're For

Living with knee pain can significantly impact your mobility and overall quality of life. If conservative methods like physical therapy or oral medications haven’t brought enough relief—and you're not ready for surgery—knee gel injections may offer a helpful middle ground.

What Are Knee Gel Injections?

Knee gel injections, or viscosupplementation, involve injecting hyaluronic acid into the knee joint. This naturally occurring substance supplements the joint’s synovial fluid, which helps lubricate and cushion the knee. Osteoarthritis reduces the quality of this fluid, making movement painful and stiff. These injections aim to restore that lost function.

Types of Injections

Two main categories of hyaluronic acid products are available:

  • Single-injection options (e.g., Synvisc-One, Monovisc)
  • Multiple-injection series (e.g., Euflexxa, Orthovisc, Supartz) administered over 3–5 weeks

They vary by source (animal-based or synthetic), molecular structure, and duration of effectiveness.

How Do They Work?

Hyaluronic acid injections offer several benefits inside the joint:

  • Improve joint lubrication and shock absorption
  • Coat exposed nerve endings to reduce pain
  • Decrease inflammation
  • Stimulate the body’s production of natural hyaluronic acid
  • Potentially slow cartilage deterioration

However, these effects are temporary, typically lasting 6 months or more depending on the patient.

The Procedure: What to Expect

Before the Injection

  • Your doctor will perform a full assessment and may use X-rays or MRIs.
  • You'll review alternative treatments.
  • Inform your provider about allergies or medications, especially if they involve blood thinners or bird-based allergens.

During the Injection

  • The site is sterilized, and local anesthesia may be used.
  • Joint fluid may be aspirated (drained) first.
  • Ultrasound guidance might be used for accuracy.
  • The hyaluronic acid is then injected into the joint.

The appointment usually takes 10–15 minutes in a medical office.

After the Injection

  • Mild swelling or soreness may occur.
  • Avoid strenuous activity for 24–48 hours.
  • Ice and light activity are usually recommended.

For multi-injection protocols, follow-up visits are scheduled weekly.

Benefits of Knee Gel Injections

1. Pain Relief

These injections can significantly reduce pain—particularly pain during activity, sleep, or transitions from sitting to standing. Relief often begins within 2–4 weeks and can last for several months.

2. Improved Mobility

Many patients regain knee flexibility and function, enabling a return to walking, climbing stairs, and other daily tasks with less discomfort.

3. Delay of Surgery

For younger patients or those with surgical risks, injections can delay or reduce the need for knee replacement surgery.

4. Less Medication Use

Successful treatment may reduce reliance on NSAIDs or opioids, minimizing side effects or dependency.

5. Minimal Downtime

Unlike surgery, gel injections are outpatient procedures with little to no recovery time and no need for rehabilitation.

Who Should Consider Knee Gel Injections?

Ideal Candidates

  • Have mild to moderate osteoarthritis (Kellgren-Lawrence grades 1–3)
  • Are under 65 years old (though older patients may also benefit)
  • Haven’t responded well to NSAIDs, physical therapy, or corticosteroid injections
  • Are looking to delay or avoid surgery
  • Have relatively preserved joint structure

Less Suitable Candidates

  • Have advanced osteoarthritis with bone-on-bone contact
  • Have inflammatory arthritis (e.g., rheumatoid arthritis)
  • Have infections or allergies to injection components
  • Are pregnant or breastfeeding
  • Have significant joint deformity or bleeding disorders

Your doctor will help determine suitability based on your condition, health status, and treatment history.

Side Effects and Risks

Common Side Effects

  • Swelling, redness, or pain at the injection site
  • Brief increase in knee stiffness or soreness
  • Minor bruising or muscle aches

These symptoms are typically short-lived and manageable with rest and ice.

Rare but Serious Risks

  • Infection (septic arthritis)
  • Severe inflammatory reactions (pseudosepsis)
  • Allergic responses (especially to avian-based products)
  • Bleeding into the joint (hemarthrosis)

Seek medical attention if you experience fever, significant swelling, intense pain, or inability to bear weight.

Limitations of Treatment

  • Relief may take weeks to appear.
  • Results vary between individuals.
  • Benefits are not permanent and repeat injections may be needed.
  • The treatment doesn’t reverse or halt osteoarthritis progression.

Cost and Insurance

  • Coverage varies by insurer and often requires prior authorization.
  • Medicare generally covers viscosupplementation for qualifying patients.
  • Out-of-pocket costs can range into the thousands if not covered.
  • Injection site (e.g., hospital vs. clinic) can impact overall expense.

Check with your insurance provider and healthcare office for specific cost details.

Complementary Therapies

Knee gel injections are often most effective when combined with:

  • Physical therapy
  • Weight loss (if overweight)
  • Bracing or orthotics
  • Lifestyle adjustments (avoiding high-impact activity)
  • Nutritional supplements (e.g., glucosamine—though evidence is mixed)
  • Experimental treatments like platelet-rich plasma (PRP)

A holistic care plan improves long-term outcomes.

Questions to Ask Your Doctor

To ensure you're well-informed, consider asking:

  • What kind of improvement can I realistically expect?
  • Which product do you recommend and why?
  • How many injections will I need?
  • Will you use imaging to guide the injection?
  • What are the side effects or warning signs I should watch for?
  • What are the costs and is it covered by insurance?
  • What additional treatments do you recommend?

Take notes and ask for printed instructions or resources if needed.

Final Thoughts

Knee gel injections can provide valuable, non-surgical relief for osteoarthritis symptoms, especially in mild to moderate cases. They work best as part of a larger treatment strategy that includes physical therapy, lifestyle adjustments, and ongoing medical support.

Though not a cure, these injections offer a low-risk option to enhance comfort, mobility, and quality of life—buying time before surgery becomes necessary or helping patients manage symptoms without it altogether.

Always consult your healthcare provider to discuss whether this treatment aligns with your condition and goals.