Viscosupplementation injections are a popular treatment option for people suffering from knee osteoarthritis. If you’re exploring ways to manage joint pain without surgery, understanding how these injections work can help you make an informed decision.

Overview: What Is Viscosupplementation?

Viscosupplementation is a minimally invasive procedure that involves injecting hyaluronic acid directly into the knee joint. Hyaluronic acid is a naturally occurring substance found in the synovial fluid that cushions and lubricates the joints. In people with osteoarthritis, the concentration of hyaluronic acid decreases, leading to joint pain and stiffness.

By injecting a hyaluronic acid preparation, viscosupplementation aims to:

• Improve joint lubrication

• Reduce pain

• Enhance mobility

• Delay the need for surgical intervention like knee replacement

How Viscosupplementation Works?

During the procedure, a doctor injects the hyaluronic acid directly into the knee joint space. The injection is guided by imaging tools, such as ultrasound, to ensure precise placement.

Depending on the brand of viscosupplementation approved by your insurance company, you might receive a single injection or a series of three to five injections over several weeks.

Who Is a Candidate for Viscosupplementation?

Viscosupplementation or hyaluronic acid (HA) injections are typically recommended for patients with mild to moderate osteoarthritis (OA) of the knee who have not found sufficient relief with conservative treatments such as physical therapy or medications and wish to delay or avoid knee surgery.

• The American Medical Society for Sports Medicine (AMSSM) recommends HA injections for patients with Kellgren-Lawrence grade II-III knee OA, particularly those over the age of 60, based on high-quality evidence demonstrating benefit using OMERACT-OARSI responder criteria [Trojian et al, 2016].

• The American Academy of Orthopaedic Surgeons (AAOS) guidelines suggest that HA injections are appropriate for patients with confirmed mild or moderate knee OA who have not responded adequately to other nonpharmacologic or pharmacologic therapies [Vangsness et al, 2020].

Viscosupplementation is typically recommended for patients who:

• Have mild to moderate osteoarthritis of the knee

• Have not found sufficient relief with conservative treatments like physical therapy or medications

• Wish to delay or avoid knee surgery

It may not be as effective for individuals with severe bone-on-bone arthritis or significant joint deformity.

What are the Benefits of Viscosupplementation Injections?

Many patients report improvements in pain and mobility following viscosupplementation treatment. Some key benefits include:

• Pain Relief: Most studies show moderate improvement in knee pain. A systematic review and meta-analysis by Bellamy et al. found that viscosupplementation significantly reduced pain, with a percent improvement from baseline of 28% to 54% for pain at 5 to 13 weeks post-injection. Another meta-analysis by Rutjes et al. reported a moderate reduction in pain intensity (effect size, -0.37).

• Enhanced Mobility: Better joint lubrication often leads to improved walking and activity levels. The study by Sun et al. demonstrated significant improvements in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, indicating enhanced mobility and function. Additionally, the Cochrane review by Bellamy et al. noted improvements in function by 9% to 32% at 5 to 13 weeks post-injection.

• Non-Surgical Option: Viscosupplementation helps manage symptoms without undergoing knee replacement surgery. The American Medical Society for Sports Medicine (AMSSM) recommends HA injections for appropriate patients with knee OA, highlighting their role in delaying the need for surgical intervention.
  

• Quick Procedure: The procedure is typically done in a doctor's office with minimal recovery time. The study by Sun et al. confirmed that a single injection of HA is safe and effective for up to 6 months, with no significant adverse events reported.

Effectiveness of Viscosupplementation for Knee OA: What does the Research Says?

Research results on viscosupplementation effectiveness are mixed, but many studies suggest that it can provide moderate pain relief for several months.

• The American Academy of Orthopaedic Surgeons (AAOS) guidelines note that intra-articular hyaluronic acid (HA) injections have shown small but statistically significant benefits for pain and function, particularly in patients with mild to moderate knee OA. However, the effectiveness can vary based on the severity of arthritis and the specific HA product used.
• A systematic review by Campbell et al. indicated that HA injections can provide improvements in knee pain and function that persist for up to 26 weeks, with a good safety profile. Despite these findings, not every patient experiences improvement, and the results can be influenced by factors such as the degree of joint degeneration and individual patient characteristics.

Typical Timeline for Results

• Initial Relief: May begin within a few weeks after the injection

• Peak Effect: Around 8 to 12 weeks post-injection

• Duration: Benefits can last up to six months in some cases

What are the Risks and Side Effects of Viscosupplementation Injections?

Like any medical procedure, viscosupplementation comes with potential risks, although serious complications are rare. Common side effects include:

• Swelling at the injection site

• Mild pain or stiffness

• Temporary warmth or redness in the knee

Rare but more serious risks include:

• Infection

• Allergic reactions

• Bleeding

• Joint swelling (pseudo-sepsis)

Types of Hyaluronic Acid Products

Several viscosupplementation products are available, including:

• Synvisc-One® (one injection)

• Orthovisc® (three injections)

• Euflexxa® (three injections)

• Hyalgan® (three to five injections)

• Monovisc® (single injection)

What to Expect During and After the Procedure?

During the Injection:

• The knee is cleaned and sterilized.

• Local anesthesia may be used to minimize discomfort.

• Hyaluronic acid is injected into the joint space.

After the Injection:

• You may be advised to limit heavy activities for 24 to 48 hours.

• Ice and over-the-counter pain relievers can help with mild soreness.

• Follow-up appointments may be scheduled if you are receiving a series of injections.

Conclusion: Is Viscosupplementation Right for You?

Viscosupplementation offers a non-surgical approach to managing knee osteoarthritis symptoms for many people. While it may not work for everyone, for some patients it can provide meaningful relief and improve quality of life, especially for those with mild to moderate arthritis.

References:

1. Bellamy N, Campbell J, Robinson V, Gee T, Bourne R, Wells G. Viscosupplementation for the treatment of osteoarthritis of the knee. Cochrane Database Syst Rev. 2006 Apr 19;2006(2):CD005321.
   
2. Campbell KA, Erickson BJ, Saltzman BM, Mascarenhas R, Bach BR Jr, Cole BJ, Verma NN. Is Local Viscosupplementation Injection Clinically Superior to Other Therapies in the Treatment of Osteoarthritis of the Knee: A Systematic Review of Overlapping Meta-analyses. Arthroscopy. 2015 Oct;31(10):2036-45.e14.
   
3. Rutjes AW, Jüni P, da Costa BR, Trelle S, Nüesch E, Reichenbach S. Viscosupplementation for osteoarthritis of the knee: a systematic review and meta-analysis. Ann Intern Med. 2012 Aug 7;157(3):180-91.
   
4. Sun SF, Hsu CW, Lin HS, Liou IH, Chen YH, Hung CL. Comparison of Single Intra-Articular Injection of Novel Hyaluronan (HYA-JOINT Plus) with Synvisc-One for Knee Osteoarthritis: A Randomized, Controlled, Double-Blind Trial of Efficacy and Safety. J Bone Joint Surg Am. 2017 Mar 15;99(6):462-471.
   
5. Trojian TH, Concoff AL, Joy SM, Hatzenbuehler JR, Saulsberry WJ, Coleman CI. AMSSM Scientific Statement Concerning Viscosupplementation Injections for Knee Osteoarthritis: Importance for Individual Patient Outcomes. Clin J Sport Med. 2016 Jan;26(1):1-11.
6. Vangsness CT Jr, Adamson TC 3rd, Daley MJ. Consequences on Private Insurance Coverage: The AAOS Clinical Practice Guidelines and Hyaluronic Acid Injections. J Bone Joint Surg Am. 2020 May 20;102(10):920-926.