Different types of knee injections for osteoarthritis

Knee pain, whether due to osteoarthritis, injury, or overuse, is a common issue that can significantly affect one’s quality of life. While physical therapy, medications, and lifestyle modifications are often first-line treatments, knee injections have become a popular option for those seeking pain relief without surgery. However, with a variety of injection types available, it’s essential to understand the differences and their effectiveness. Below, we explore the most common types of knee injections and how well they work for managing knee pain. As ever, weight management, leg strength, and muscle stability are amongst the most effective treatments for osteoarthritis in the knee, we have over 20 years of experience in this, see our 50+ fitness page. 

1. Corticosteroid Injections

Corticosteroid injections, commonly referred to as cortisone shots, are one of the most widely used treatments for knee pain, especially in cases of osteoarthritis and inflammatory conditions.

How They Work:

Corticosteroids are powerful anti-inflammatory medications. When injected directly into the knee joint, they reduce inflammation and relieve pain, often within a few days.

Effectiveness:

• Short-term relief: Corticosteroids are generally effective for quick pain relief, often lasting from a few weeks to several months. However, their effects diminish over time, and repeated use may lead to diminishing returns.
• Limitations: Studies suggest that while cortisone shots offer relief in the short term, their long-term benefits are limited. Overuse can also lead to cartilage damage and joint deterioration, so doctors typically recommend limiting the frequency of these injections to a few times per year.
• Study Findings: A 2015 study published in JAMA compared corticosteroid injections to placebo in patients with knee osteoarthritis. The study found that while corticosteroids provided short-term pain relief, repeated use did not prevent disease progression and could lead to cartilage damage over time.

2. Hyaluronic Acid (Viscosupplementation) Injections

Hyaluronic acid injections, also known as viscosupplementation, involve injecting a gel-like substance directly into the knee joint. This type of injection is often recommended for those with mild to moderate osteoarthritis.

How They Work:

Hyaluronic acid is a naturally occurring substance found in the synovial fluid of joints. It acts as a lubricant and shock absorber, helping the joint move smoothly. In people with osteoarthritis, the amount and quality of hyaluronic acid decrease, leading to pain and stiffness.

Effectiveness:

• Mixed results: Studies on hyaluronic acid injections have shown mixed outcomes. Some patients report significant pain relief and improved mobility, especially for moderate arthritis, while others find minimal improvement.
• Duration: When effective, the benefits can last anywhere from six months to a year, but the relief is usually less immediate compared to corticosteroid injections.
• Best suited for early-stage osteoarthritis: This option tends to work best for individuals with mild to moderate arthritis. It may not be as effective for those with severe joint damage.
• Study Findings: A large meta-analysis published in The American Journal of Sports Medicine in 2015 reviewed multiple studies on HA injections for knee osteoarthritis. The researchers concluded that HA injections provided moderate pain relief lasting up to 6 months, especially in patients with early-stage arthritis.
• Longer-term relief: The study found that patients experienced pain relief for up to 26 weeks, though the magnitude of the effect varied across studies.
• Limitations: HA injections are generally less effective for severe osteoarthritis, and results can be variable depending on individual patient factors.

Authors note _ I have been having these for 2 years, and have found them effective, reducing knee pain in my right knee by around 80%, although the effect is subtle at first but then increases over time after injection. However, the latest injection seems to have been less effective, perhaps an indication that my knee damage is now more extensive and it is time to try something else more hardcore!!

3. Platelet-Rich Plasma (PRP) Injections

PRP injections have gained popularity as a regenerative medicine option, especially for younger patients and those seeking natural treatments.

How They Work:

PRP is made from the patient’s own blood, which is spun in a centrifuge to concentrate the platelets. These platelets contain growth factors that promote healing and tissue regeneration. When injected into the knee, PRP is thought to help repair damaged tissues and reduce inflammation.

Effectiveness:

• Promising for early to moderate arthritis: Some research shows that PRP injections can provide longer-lasting pain relief compared to corticosteroids and hyaluronic acid, especially in younger patients or those with less advanced arthritis.
• Variable outcomes: The effectiveness of PRP is still being studied, but many patients report benefits lasting several months to over a year. However, it may take several weeks to notice improvements, and the procedure often requires multiple injections.
• Regenerative potential: PRP is considered a more holistic approach, aiming to repair tissue rather than just reduce inflammation, which makes it appealing to many.
• Limitations: The effectiveness of PRP can vary based on the preparation methods and the severity of osteoarthritis. PRP may take longer to show results, and multiple injections are often required.

4. Stem Cell Injections

Stem cell therapy is one of the most cutting-edge treatments in orthopedics. It involves injecting stem cells—often derived from the patient’s bone marrow or adipose (fat) tissue—into the knee joint.

How They Work:

Stem cells have the potential to differentiate into various types of cells, including cartilage cells. The goal of stem cell injections is to regenerate damaged tissues and potentially reverse the progression of osteoarthritis.

Effectiveness:

• Early-stage research: While stem cell injections show promise, they are still in the experimental phase, and research is ongoing. Some patients report significant pain relief and even cartilage regeneration, but these outcomes are not guaranteed.
• Long-term potential: Stem cell injections could offer long-lasting relief and regeneration, but the lack of consistent data and high costs make them less accessible for now.
• Safety and risks: While generally considered safe, stem cell therapies are still relatively new, and more studies are needed to confirm their long-term efficacy and safety.
• Study Findings: A 2016 study published in The American Journal of Sports Medicine explored the effects of stem cell injections in patients with knee osteoarthritis. The study found that stem cell injections provided significant improvements in pain and function over 12 months, with some evidence of cartilage regeneration observed in MRI scans .
• Long-term potential: This treatment offers the possibility of not only reducing pain but also repairing damaged tissue.
• Limitations: Stem cell therapy remains expensive, and its long-term effectiveness is still under investigation. While some patients report substantial improvements, others see limited benefit.

5. Prolotherapy

Prolotherapy, also known as proliferative therapy, involves injecting an irritant solution—usually dextrose—into the knee joint to stimulate the body’s natural healing response.

How They Work:

The solution causes localized inflammation, which in turn triggers the body to produce new tissue and repair the damaged area. Prolotherapy aims to strengthen weakened ligaments, tendons, and cartilage over time.

Effectiveness:

• Study Findings: A 2017 randomized controlled trial published in Annals of Family Medicine found that prolotherapy significantly reduced pain and improved function in patients with knee osteoarthritis compared to saline injections. The benefits lasted for up to 12 months.
• Gradual improvement: While prolotherapy does not provide immediate relief, patients tend to see improvements over several weeks as the tissue repairs.
• Limitations: Prolotherapy has less scientific backing than other treatments, and multiple injections are typically required over several months to achieve optimal results.

6. Arthrosamid Injections

Arthrosamid is a relatively new type of injection designed to treat knee osteoarthritis. Unlike other injections, Arthrosamid uses a hydrogel, which is a non-biodegradable substance that integrates into the soft tissue of the knee to provide lasting lubrication and cushioning.

How They Work:

Arthrosamid contains a unique hydrogel made of 97.5% water and 2.5% cross-linked polyacrylamide. When injected into the knee joint, the hydrogel forms a cushioning layer that helps improve joint mobility and reduces friction between bones. This effect is particularly useful for people suffering from osteoarthritis, where the cartilage is worn down, causing painful bone-on-bone contact.

Effectiveness:

• Long-lasting relief: Arthrosamid injections have shown promising results in providing long-term pain relief. Clinical studies suggest that many patients experience significant pain reduction that lasts up to 2 years or more after a single injection. This is much longer than corticosteroid or hyaluronic acid injections.
• Gradual improvement: While the pain relief may not be immediate, patients typically begin to notice improvement within a few weeks after the injection, with continued benefits over time as the hydrogel integrates into the joint.
• Minimally invasive: Arthrosamid is a minimally invasive treatment option with fewer side effects compared to more aggressive options like surgery. It is particularly appealing to those with moderate to severe osteoarthritis who are not yet candidates for joint replacement surgery.
• Safety: Early studies and real-world use suggest Arthrosamid has a favorable safety profile. Unlike corticosteroids, which can lead to cartilage damage with repeated use, Arthrosamid provides cushioning without breaking down tissues. Additionally, because the hydrogel is non-biodegradable, it stays in the joint, providing sustained relief without the need for frequent re-injections.
• Study Findings: A 2021 study published in The Knee investigated the long-term effects of Arthrosamid in patients with moderate to severe knee osteoarthritis. The study reported significant improvements in pain, stiffness, and overall knee function, with benefits lasting up to 2 years after a single injection.

Different types of knee injections for osteoarthritis Conclusion: Which Knee Injection is Right for You?

When deciding on the best knee injection, it’s important to consider the cause of your knee pain, the severity of your condition, and your treatment goals. Here’s a summary to help guide your decision:

• Corticosteroid injections: Best for short-term, quick relief of inflammation and pain, particularly in osteoarthritis and inflammatory conditions.
• Hyaluronic acid injections: Useful for mild to moderate osteoarthritis, offering longer-term relief with minimal side effects.
• PRP injections: A promising option for early to moderate osteoarthritis, with potential for longer-lasting relief and tissue repair.
• Stem cell injections: Experimental but potentially regenerative for joint tissues, ideal for patients looking for innovative treatments.
• Prolotherapy: A slower but potentially effective option for ligament injuries or mild arthritis, focusing on promoting the body’s natural healing process.
• Arthrosamid; is best suited for individuals with knee osteoarthritis who have tried other non-surgical treatments, such as corticosteroids or hyaluronic acid injections but are looking for longer-lasting results. It can also be an option for those wanting to delay knee replacement surgery or those who cannot undergo surgery due to health reasons.

Ultimately, the effectiveness of each type of knee injection can vary depending on the individual, and consulting with a healthcare provider is essential in making the right choice for your specific situation. While injections can provide significant relief, they are often part of a broader treatment plan that includes physical therapy, weight management, and lifestyle modifications.

 

References:

1. JAMA. 2015; Effects of Intra-articular Corticosteroids on Knee Osteoarthritis.
2. The American Journal of Sports Medicine. 2015; Meta-analysis of Hyaluronic Acid Injections for Knee Osteoarthritis.
3. Arthroscopy: The Journal of Arthroscopic and Related Surgery. 2020; PRP vs. Corticosteroids in Knee Osteoarthritis.
4. The American Journal of Sports Medicine. 2016; Stem Cell Therapy for Knee Osteoarthritis.
5. Annals of Family Medicine. 2017; Prolotherapy for Knee Osteoarthritis.
6. The Knee. 2021; Long-term Outcomes of Arthrosamid Hydrogel Injections for Knee Osteoarthritis.