PRP vs Hyaluronic Acid Injections for Knee Arthritis: Which Is Better?
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By Dr. Jeffrey Peng, MD · Published March 5, 2025 · 7 min read
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If you have been diagnosed with knee osteoarthritis and are exploring injection options, two of the most common treatments you will encounter are platelet-rich plasma (PRP) and hyaluronic acid (HA) injections. Both are well-established, evidence-based treatments that can reduce pain and improve function, but they work through different mechanisms and come with different cost and insurance considerations. Understanding how they compare can help you and your healthcare provider choose the right approach for your situation.
What Is Hyaluronic Acid?
Hyaluronic acid is a naturally occurring substance found in synovial fluid, the fluid that lubricates and cushions your joints. In osteoarthritis, the quality and quantity of synovial fluid deteriorates over time. When injected directly into the knee, hyaluronic acid acts as both a lubricant and an anti-inflammatory agent. The goal of HA therapy, sometimes called viscosupplementation, is to restore the normal viscosity and elasticity of the synovial fluid, which can help improve joint mobility and reduce pain.
How Do PRP Injections Work?
PRP injections involve drawing a small sample of your own blood, concentrating the platelets in a centrifuge, and then injecting that concentrated solution directly into the knee joint. Platelets contain a high density of growth factors that activate the body’s own natural repair mechanisms. Randomized controlled trials have demonstrated that PRP can lower inflammatory markers such as IL-1β and TNF-α inside the knee joint, resulting in healthier cartilage and potentially slower arthritis progression.
Which Injection Is More Effective for Knee Arthritis?
A 2023 systematic review and meta-analysis including 14 randomized controlled trials directly compared PRP and hyaluronic acid injections for knee osteoarthritis (Li et al., 2023). The findings consistently favored PRP across multiple outcome measures.
In terms of pain relief, PRP injections resulted in significantly lower visual analog scale (VAS) pain scores at both 3 months and 12 months compared to hyaluronic acid. Functional outcomes told a similar story. The researchers assessed the WOMAC osteoarthritis index, which measures physical function, pain, and stiffness, and found that PRP produced considerably better scores at 1, 3, 6, and 12 months. They also evaluated IKDC scores, which measure knee symptoms, function, and sports activity levels. PRP led to significantly better IKDC scores at 3 and 6 months, though by 12 months the two treatments showed equivalent results on this measure.
Regarding side effects, the meta-analysis found no differences in overall complication rates between the two groups, although PRP did lead to higher rates of temporary local pain at the injection site. The authors concluded that for patients with knee osteoarthritis, PRP can effectively relieve pain, enhance joint function, and improve quality of life compared to hyaluronic acid injections.
Can You Combine PRP and Hyaluronic Acid Injections?
Because PRP and hyaluronic acid work through different mechanisms, many providers have theorized that combining the two could produce an additive or synergistic effect. A systematic review examined whether combination therapy (PRP plus HA) is more effective than either treatment alone for knee osteoarthritis (Baria et al., 2022). The researchers found that combination therapy was superior to hyaluronic acid alone. However, combination therapy was not superior to PRP alone. This is an important finding: adding hyaluronic acid to PRP does not appear to offer a meaningful benefit beyond what PRP provides on its own.
How Much Do PRP and Hyaluronic Acid Injections Cost?
Cost is one of the most significant differences between these two treatments. PRP injections are not covered by insurance in most cases. According to a study examining the cost variability of orthobiologics, the average cost of PRP treatment in the United States is approximately $700 per injection (Momaya et al., 2020). Depending on the severity of your arthritis, you may need one to three injections followed by annual booster treatments, which adds to the total out-of-pocket expense.
In contrast, hyaluronic acid injections are covered by many private insurance plans as well as Medicare and most Medicaid programs. It is worth noting that while HA injections are typically covered for knee arthritis, they are often not covered for arthritis in other joints such as the hips, ankles, or shoulders. If your insurance covers hyaluronic acid, it may make financial sense to try HA treatment first before considering PRP. Most insurance plans cover HA injections every six months, making them a viable option for ongoing maintenance.
When Is Hyaluronic Acid a Better Choice Than PRP?
While the evidence favors PRP for most patients, there are several clinical scenarios where hyaluronic acid may be the more appropriate choice.
Patients on antiplatelet medications. Individuals with underlying cardiovascular disease who take antiplatelet agents such as aspirin or clopidogrel should generally avoid PRP. These patients would need to discontinue their antiplatelet medications for four to six weeks before a PRP injection, which could significantly increase the risk of a major cardiovascular event. In these cases, hyaluronic acid is an effective alternative that does not require any medication changes.
Patients with inflammatory arthritis. Those with conditions like rheumatoid arthritis who require daily NSAIDs or low-dose steroids to manage symptoms may not be ideal PRP candidates. NSAIDs can interfere with platelet function and reduce the effectiveness of PRP. The same applies to patients who need to take NSAIDs for other medical conditions or following other procedures.
Budget considerations. For patients who cannot afford the out-of-pocket expense of PRP, insurance-covered hyaluronic acid injections provide a reliable, evidence-based treatment option that can deliver meaningful pain relief and improved function.
How Safe Are PRP and Hyaluronic Acid Injections?
Both PRP and hyaluronic acid injections have excellent safety profiles with minimal side effects. All injections carry a small risk of infection, but using sterile technique reduces this risk to near zero. Hyaluronic acid injections carry a slight risk of allergic reaction, whereas PRP, which is derived from your own blood, has virtually no risk of an allergic response.
PRP injections do tend to cause higher rates of post-injection pain, swelling, and soreness. This occurs because the activation of platelets and the release of growth factors trigger a localized inflammatory response. Although this reaction typically resolves within a few days, it can be uncomfortable. In my practice, I advise patients who receive PRP to take one to two weeks off from vigorous exercise and to avoid activities that place excessive pressure on the knee, as this can interfere with platelet activation and treatment outcomes. With hyaluronic acid injections, there are generally no such restrictions on physical activity.
Why Ultrasound Guidance Is Essential for Knee Injections
Regardless of which injection you choose, one factor can significantly impact your results: whether the injection is performed with ultrasound guidance. Both PRP and hyaluronic acid injections should be administered with imaging guidance to ensure accurate needle placement within the joint.
A comprehensive review of the evidence on injection accuracy found striking differences between ultrasound-guided and landmark-based techniques across virtually every joint (Daniels et al., 2018). For knee injections specifically, ultrasound guidance achieves accuracy rates of 96 to 100 percent, while landmark-based techniques range from as low as 55 percent to 100 percent depending on the clinician’s experience. Similar patterns hold for the shoulder, hip, elbow, and foot and ankle joints.
In my practice, every injection is performed under direct ultrasound visualization. If you are paying out of pocket for PRP, or relying on insurance-covered hyaluronic acid for pain relief, you want to ensure that the medication reaches the intended target. I recommend asking your healthcare provider whether they use ultrasound guidance before scheduling any injection.
Not All PRP Is the Same: Why Dosing Matters
If you do choose PRP, it is important to understand that not all PRP preparations are equivalent. Recent research has focused on the dose-response relationship of PRP, demonstrating that low-dose PRP does not yield satisfactory outcomes and may perform no better than placebo. In contrast, high-dose PRP produces substantially better results.
I recommend asking your healthcare provider about the volume of blood they plan to draw for your PRP injection. For larger joints such as knees, hips, and shoulders, a blood draw of approximately 60 cc is ideal, which will yield roughly 10 billion platelets. For smaller joints like those in the wrists or feet, a 30 cc blood draw is generally sufficient. The concentration and platelet count of your PRP preparation can make a meaningful difference in your clinical outcomes.
The Bottom Line
If cost were not a consideration, PRP injections would be the recommended first-line treatment for most patients with mild to moderate knee osteoarthritis. PRP offers superior pain relief, better functional outcomes, and longer-lasting effects compared to hyaluronic acid. Some evidence suggests that a single high-dose PRP injection can provide benefits lasting an entire year, whereas hyaluronic acid typically requires a series of three injections every six months. PRP has also been shown to help protect healthy cartilage and slow arthritis progression.
That said, both PRP and hyaluronic acid are excellent treatment options. It is important to remember that injections are just one component of a comprehensive, multimodal approach to managing knee osteoarthritis. Exercise and physical therapy remain fundamental pillars of treatment and should be pursued alongside any injection therapy.
References
1. Li S, Xing F, Yan T, Zhang S, Chen F. Multiple Injections of Platelet-Rich Plasma Versus Hyaluronic Acid for Knee Osteoarthritis: A Systematic Review and Meta-Analysis of Current Evidence in Randomized Controlled Trials. J Pers Med. 2023;13(3):429. doi:10.3390/jpm13030429
2. Baria MR, Vasileff WK, Kempton LB, et al. Treating Knee Osteoarthritis With Platelet-Rich Plasma and Hyaluronic Acid Combination Therapy: A Systematic Review. Am J Sports Med. 2022;50(1):273-281. doi:10.1177/0363546521998010
3. Momaya AM, Ibañez F, Treme GP, Kvitne RS. The Cost Variability of Orthobiologics. Sports Health. 2020;12(1):94-98. doi:10.1177/1941738119880256
4. Daniels EW, Cole D, Jacobs B, Phillips SF. Existing Evidence on Ultrasound-Guided Injections in Sports Medicine. Orthop J Sports Med. 2018;6(2):2325967118756576. doi:10.1177/2325967118756576
Medical Disclaimer: This content is for educational purposes only and does not substitute for the medical advice of a physician. Always consult your healthcare provider before beginning any new treatment program. The information presented reflects the opinion of Dr. Jeffrey Peng and does not represent the views of his employers or affiliated hospital systems.
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