Knee osteoarthritis is a common condition affecting millions of people worldwide, causing pain, stiffness, and reduced mobility. While conventional treatments such as pain medication, physiotherapy, and steroid injections can provide temporary relief, platelet-rich plasma (PRP) injections are a promising alternative for managing osteoarthritis symptoms. This blog will explain what PRP is, its different types, how it compares to other treatments, and whether it might be the right option for you.
What is PRP?
PRP is a concentration of platelets derived from your own blood. Platelets play an important role in the body's natural healing process, as they contain growth factors and proteins that aid tissue repair. PRP therapy involves obtaining a sample of blood, processing it to concentrate the platelets, and injecting the PRP directly into the knee joint. The goal is to stimulate the body’s healing response and reduce inflammation, thereby relieving pain and improving joint function.
Types of PRP
PRP can be classified based on the presence or absence of white blood cells (leukocytes). The two main types are:
Leukocyte-Rich PRP (LR-PRP): Contains a higher concentration of white blood cells. While leukocytes play a role in immune response, their presence in PRP may lead to more inflammation initially. LR-PRP is often preferred for treating tendinopathies, such as tennis elbow or Achilles tendinopathy, where enhanced inflammation can stimulate tissue repair.
Leukocyte-Poor PRP (LP-PRP): Has fewer white blood cells, resulting in less post-injection inflammation. LP-PRP is typically recommended for osteoarthritis treatment, as excessive inflammation can worsen joint symptoms. Its anti-inflammatory properties help reduce pain and improve mobility in patients with mild knee osteoarthritis.
When preparing PRP, using a tube with a separator gel is essential to obtain a high-quality LP-PRP. The separator gel helps in isolating the plasma from red and white blood cells during centrifugation, ensuring minimal leukocyte content in the final PRP product. This preparation method is crucial for achieving optimal outcomes in osteoarthritis treatment by reducing unnecessary inflammation.
PRP for Osteoarthritis vs. PRP for Tendinopathy
Although both osteoarthritis and tendinopathy involve degenerative changes, the treatment goals differ. In osteoarthritis, the primary aim of PRP is to reduce inflammation and slow disease progression, making LP-PRP the preferred choice. For tendinopathy, where poor healing and chronic inflammation are key issues, LR-PRP is more beneficial due to its ability to provoke a stronger regenerative response by increasing inflammation initially. Proper selection of PRP type ensures the best therapeutic outcome for each condition.
Results of PRP in Osteoarthritis
Several studies have demonstrated the efficacy of platelet-rich plasma (PRP) injections in alleviating pain and enhancing function in patients with knee osteoarthritis. A meta-analysis published in the American Journal of Sports Medicine analysed multiple randomised controlled trials comparing PRP injections to placebo and other treatments. The analysis revealed that PRP injections led to significant improvements in pain relief and functional outcomes compared to control treatments.
A randomised clinical trial involving 288 adults aged 50 years or older with mild to moderate knee osteoarthritis compared PRP injections to placebo. The study found that PRP treatment resulted in a mean change in knee pain scores of −2.1 on an 11-point scale, compared to −1.8 in the placebo group, indicating a modest improvement in pain relief with PRP.
Additionally, a systematic review and meta-analysis published in the British Journal of Sports Medicine assessed the efficacy of PRP injections in knee osteoarthritis. The review concluded that PRP injections were associated with significant pain reduction and functional improvement
While PRP injections may not reverse the structural changes of osteoarthritis, they can help slow disease progression and improve quality of life. The duration of symptom relief varies among patients, with many reporting benefits lasting up to 6-12 months after the procedure. It's important to note that individual responses can differ, and further research is ongoing to optimise treatment protocols and long-term outcomes.
In summary, PRP injections have shown good results in reducing pain and enhancing function in knee osteoarthritis patients, offering a potential alternative to traditional treatments. However, patients should consult with their healthcare provider to determine the most appropriate treatment plan based on their specific condition and medical history.
Comparing PRP to Steroid Injections
Steroid injections have long been used to reduce inflammation and provide quick pain relief. However, their effects are usually short-lived (lasting a few weeks to a few months), and repeated use can weaken joint tissues over time.
PRP, on the other hand, promotes tissue healing rather than just suppressing inflammation. While it may take longer to notice significant improvement after PRP injections (usually a few weeks), the results tend to last longer without the tissue-degrading effects associated with steroids.
Comparing PRP to Hyaluronic Acid Injections
Hyaluronic acid (HA) injections aim to improve joint lubrication and reduce friction. They can be effective for temporary relief, particularly in mild to moderate osteoarthritis. However, HA does not address the underlying inflammation or promote healing.
In contrast, PRP injections work by stimulating the body’s natural repair mechanisms. Studies comparing PRP and HA injections suggest that PRP provides more significant pain relief and better functional outcomes over time. HA, however, provides better results in patients with moderate osteoarthritis of the knee when compared to PRP.
Which Patients with Knee Osteoarthritis are Ideal for PRP Injections?
PRP therapy may be suitable for patients who:
Have mild knee osteoarthritis.
Are looking for non-surgical treatment options.
Have not found lasting relief with other treatments like steroids or HA injections.
Want to avoid or delay knee replacement surgery.
The recommended volume of PRP to be injected typically ranges from 3 to 6 milliliters per knee. Studies have suggested that higher volumes may enhance the therapeutic effect without increasing complications, but the exact volume should be determined by the treating clinician based on individual patient factors.
Patients with advanced osteoarthritis or significant joint deformity may not benefit as much from PRP. However, an alternative injection treatment known as Arthrosamid, a hydrogel designed to provide long-lasting cushioning in the joint, may offer relief for such patients. Arthrosamid acts by increasing joint lubrication and reducing friction, making it a suitable option for those seeking non-surgical pain relief.
A thorough assessment by a specialist is essential to determine whether PRP, Arthrosamid, or another treatment is right for you. Contact ACTIVATE Musculoskeletal Clinic today to explore the best options for your knee osteoarthritis management. You could also explore potential injection therapies by using our digital tool.
What to Expect During the Procedure
The PRP procedure is relatively quick and minimally invasive. Here's what to expect:
Blood Draw: A sample of your blood is taken, typically from your arm.
Processing: The blood sample is placed in a centrifuge, which spins it at high speed to separate the platelets from other blood components.
Injection: The concentrated PRP is injected into the affected knee joint. Ultrasound guidance may be used to ensure precise placement.
The entire process takes about 30-45 minutes. Most patients can resume normal activities the same day, although it is advisable to avoid strenuous activities like running for a few days.
Summary
PRP injections offer a natural, regenerative approach to managing knee osteoarthritis. Compared to conventional treatments like steroids, PRP provides longer-lasting relief by promoting tissue healing. Ideal candidates are those with mild osteoarthritis who want to avoid surgery.
At ACTIVATE Musculoskeletal Clinic, we provide PRP therapy and other advanced treatments for knee osteoarthritis. If you’re interested in learning more or booking a consultation, contact us today. Let us help you get back to doing the activities you love, pain-free. Ready to take the next step towards knee pain relief? Book your consultation at ACTIVATE Musculoskeletal Clinic now!
About the Author: Dr. Mustafa Alnaib MBChB, MRCS, MSc, FEBOT is an orthopaedic surgeon, musculoskeletal doctor and Clinic Director at ACTIVATE Musculoskeletal Clinic in Kent and London
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