Cortisone vs. PRP Injections for Knee Arthritis: What the Research Shows
- Mar 1
- 8 min read
Written by Dr. Jeffrey Peng, MD — Board-Certified Sports Medicine Physician
Published: March 1, 2026 | Last Updated: March 1, 2026
A cortisone injection for knee arthritis can feel like a miracle. The pain fades, movement returns, and for a brief moment, life feels normal again. But beneath that relief, there is a growing concern — one now backed by real evidence. What helps today may quietly be harming your knee for tomorrow.
In my practice as a sports medicine physician, I have treated thousands of patients with joint pain and helped them navigate injection therapies. For years, I used both cortisone and PRP — but as the research has evolved, so has my approach. In this article, I will explain how each treatment works, when I use them, and most importantly, what the science now tells us about their long-term effects on your knee.
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What Is Knee Osteoarthritis?
Knee osteoarthritis is one of the most common causes of joint pain and stiffness as we age. It is a progressive condition, meaning it gradually worsens over time. While there is no cure, there are effective ways to manage symptoms and slow its progression. For many patients, that journey often begins with an injection.
One of the most common options has been around for decades: cortisone. Corticosteroid injections are inexpensive, fast-acting, and almost every primary care doctor or orthopedic specialist is familiar with them. Platelet-rich plasma, or PRP, on the other hand, is newer. It involves drawing your own blood, concentrating the platelets, and injecting that preparation back into the joint to help modulate inflammation and promote healing. Both can provide relief — but how they work, and what they do to the joint over time, is very different.
How Cortisone Injections Work — and Their Hidden Risks
Cortisone works by powerfully suppressing inflammation. When injected into the knee joint, it often provides fast relief — sometimes within just a few days. For patients dealing with constant aching or a painful flare-up, it can feel transformative. That is why it has been used for so long: it works, at least in the short term.
However, recent studies have raised serious concerns about what cortisone may be doing beneath the surface. A 2017 randomized controlled trial published in JAMA compared intra-articular triamcinolone to saline in patients with knee osteoarthritis. The results were striking: patients receiving cortisone had significantly more cartilage loss than those receiving saline — despite no significant difference in pain outcomes (McAlindon et al., 2017).
Newer studies are sounding similar alarms. A 2025 study published in Radiology followed patients for two years using MRI and found that corticosteroid injections were associated with greater osteoarthritis progression compared to both hyaluronic acid injections and controls. While both cortisone and hyaluronic acid reduced pain after injection, only cortisone was linked to higher cartilage degeneration on imaging (Bharadwaj et al., 2025).
The data extends beyond the knee as well. A 2020 observational study using data from the Osteoarthritis Initiative found that patients who received corticosteroid injections had a significantly increased risk of eventually requiring knee arthroplasty, with each injection raising the absolute risk by 9.4% at nine-year follow-up (Wijn et al., 2020). And in the hip, a 2021 study in the Journal of Bone and Joint Surgery found that intra-articular corticosteroids were associated with an 8.5 times higher risk of rapidly destructive joint disease, with the risk increasing alongside dosage and number of injections (Okike et al., 2021). The takeaway is clear: cortisone is not neutral. Relief today may come at the cost of cartilage tomorrow.
When Does a Cortisone Injection Still Make Sense?
Despite these concerns, there are still situations where I believe cortisone has a role. The key is to use it judiciously — with a clear purpose and a plan.
In my practice, I occasionally recommend cortisone for patients dealing with a major life event where pain relief is urgently needed. A once-in-a-lifetime vacation, a daughter's wedding, a family reunion — these are moments where a patient needs to walk, move, and enjoy life, and a well-timed cortisone injection can make that possible.
I also use it for patients with end-stage osteoarthritis — those with severe, bone-on-bone changes who are already scheduled for a knee replacement. In these cases, the goal is no longer to preserve cartilage. It is to reduce suffering while the patient waits for surgery. Keep in mind that cortisone should generally be avoided within three months of a planned knee replacement, as it may increase the risk of post-operative joint infection.
In both situations, I make the same point clear: cortisone is not a long-term fix. It should never be used on a routine or recurring basis. Instead, it should be viewed as a bridge — one that gets you across a short-term obstacle without sacrificing what remains of the joint.
How Does PRP Work Differently?
Platelet-rich plasma takes a fundamentally different approach. Instead of shutting down inflammation like cortisone, PRP works by modulating it — supporting the body's natural healing processes rather than suppressing them.
The process begins with a blood draw, usually between 60 and 120 cc, though higher volumes may be needed for older patients or those with more severe arthritis. That blood is then spun in a centrifuge to concentrate the platelets — tiny cell fragments loaded with growth factors and signaling molecules. The final product is injected directly into the knee joint, where it works to reduce inflammatory signaling, recruit repair cells, and potentially support cartilage preservation.
Relief does not happen overnight. It can take several weeks to notice an improvement, and sometimes multiple injections are needed. But for many patients, the effects are longer-lasting — often six to twelve months, and sometimes more. And unlike cortisone, which may accelerate joint degeneration with repeated use, PRP appears to do the opposite. It is not a miracle cure and it will not regrow a brand new joint, but it is the first treatment I have used in my practice that seems to help the knee function better over time, not just feel better for a few weeks.
Can PRP Preserve or Regenerate Cartilage?
One of the most exciting developments in recent years is the growing body of evidence suggesting that PRP may do more than relieve pain — it might actually help preserve or even regenerate cartilage in osteoarthritic knees.
A 2022 multicenter randomized controlled trial published in Knee Surgery, Sports Traumatology, Arthroscopy followed over 600 patients who received either PRP or sham saline injections, with follow-up extending to 60 months. The PRP group showed sustained clinical improvement at 24 months where the saline group did not. Importantly, tibiofemoral cartilage volume decreased significantly less in the PRP group over the five-year follow-up period (Chu et al., 2022).
A 2024 study published in the Indian Journal of Orthopaedics used ultrasound imaging to evaluate cartilage thickness and integrity in patients receiving PRP. The results were encouraging: patients showed signs of increased cartilage thickness and improved structural appearance by 180 days post-injection, suggesting a potential for early cartilage regeneration, especially in those with mild to moderate arthritis (Pundkar et al., 2024).
PRP vs. Cortisone: What the Meta-Analyses Show
When we look at direct comparisons through randomized controlled trials and meta-analyses, a clear trend emerges: while cortisone may offer quicker initial relief, PRP provides more durable and clinically meaningful benefits over the long term.
A 2024 systematic review and meta-analysis published in EFORT Open Reviews analyzed 35 randomized controlled trials involving over 3,300 patients with knee osteoarthritis, directly comparing cortisone, hyaluronic acid, and PRP. In the short term, cortisone and PRP performed similarly. But beyond that initial window, PRP outperformed cortisone at every follow-up point — and these differences exceeded the minimal clinically important difference (MCID), meaning patients were experiencing real, noticeable improvements in pain and function (Bensa et al., 2024).
A separate network meta-analysis published in Arthroscopy reviewed 48 randomized trials encompassing more than 9,000 knees treated with corticosteroids, hyaluronic acid, PRP, or bone marrow aspirate concentrate. At a minimum of six months follow-up, PRP emerged as the clear leader. It produced significant improvements in both pain and function compared to placebo, and ranked highest overall among all treatments with a SUCRA score exceeding 91 — meaning it had the highest probability of delivering meaningful clinical improvement. Corticosteroids, by comparison, had a SUCRA score of just 15, barely outperforming placebo (Jawanda et al., 2024).
Additionally, a 2025 meta-analysis in the American Journal of Sports Medicine evaluated 18 randomized controlled trials comparing PRP to placebo and confirmed that PRP provided clinically relevant functional improvement at all follow-up points from one to twelve months. Notably, the study found that platelet concentration matters: high-platelet PRP delivered superior and more durable pain relief compared to low-platelet preparations (Bensa et al., 2025). This underscores that not all PRP is created equal — the way it is prepared and delivered can dramatically affect results.
How to Decide Between PRP and Cortisone for Your Knee
The right choice depends on your goals, your timeline, and your specific situation.
If you are looking for quick, short-term relief — perhaps for an upcoming trip, a major event, or a temporary flare-up — cortisone may still make sense. But it should be used sparingly and with a clear understanding of the potential risks. It is not a tool for long-term management.
If your goal is to preserve your knee, stay active, and reduce the likelihood of surgery — especially if you are in the earlier stages of arthritis — PRP is often the better investment. It will not work overnight, but it offers the potential for longer-lasting relief without accelerating joint damage. In some cases, it may even help support the healing environment within the joint.
No treatment is perfect. But the conversation in sports medicine is shifting — from temporarily masking symptoms to embracing therapies that promote long-term joint health. If you are considering PRP, keep in mind that how it is prepared matters significantly. Not all PRP is created equal, and the concentration and quality of the preparation can make a meaningful difference in your outcome.
References
McAlindon TE, LaValley MP, Harvey WF, et al. Effect of intra-articular triamcinolone vs saline on knee cartilage volume and pain in patients with knee osteoarthritis: a randomized clinical trial. JAMA. 2017;317(19):1967-1975. doi:10.1001/jama.2017.5283
Bharadwaj UU, Lynch JA, Joseph GB, et al. Intra-articular knee injections and progression of knee osteoarthritis: data from the Osteoarthritis Initiative. Radiology. 2025;315(2):e233081. doi:10.1148/radiol.233081
Wijn SRW, Rovers MM, van Tienen TG, Hannink G. Intra-articular corticosteroid injections increase the risk of requiring knee arthroplasty. Bone Joint J. 2020;102-B(5):586-592. doi:10.1302/0301-620X.102B5.BJJ-2019-1376.R1
Okike K, King RK, Merchant JC, et al. Rapidly destructive hip disease following intra-articular corticosteroid injection of the hip. J Bone Joint Surg Am. 2021;103(22):2070-2079. doi:10.2106/JBJS.20.02155
Chu J, Duan W, Yu Z, et al. Intra-articular injections of platelet-rich plasma decrease pain and improve functional outcomes than sham saline in patients with knee osteoarthritis. Knee Surg Sports Traumatol Arthrosc. 2022;30(12):4063-4071. doi:10.1007/s00167-022-06887-7
Pundkar AG, Shrivastava S, Chandanwale R, Jaiswal A, Patel H. Exploring the efficacy of biologics in knee osteoarthritis: ultrasound evaluation of cartilage regeneration effects. Indian J Orthop. 2024;58(8):1009-1015. doi:10.1007/s43465-024-01199-z
Bensa A, Sangiorgio A, Boffa A, et al. Corticosteroid injections for knee osteoarthritis offer clinical benefits similar to hyaluronic acid and lower than platelet-rich plasma: a systematic review and meta-analysis. EFORT Open Rev. 2024;9(9):883-895. doi:10.1530/EOR-23-0198
Jawanda H, Khan ZA, Warrier AA, et al. Platelet-rich plasma, bone marrow aspirate concentrate, and hyaluronic acid injections outperform corticosteroids in pain and function scores at a minimum of 6 months as intra-articular injections for knee osteoarthritis: a systematic review and network meta-analysis. Arthroscopy. 2024;40(5):1623-1636.e1. doi:10.1016/j.arthro.2024.01.037
Bensa A, Previtali D, Sangiorgio A, et al. PRP injections for the treatment of knee osteoarthritis: the improvement is clinically significant and influenced by platelet concentration: a meta-analysis of randomized controlled trials. Am J Sports Med. 2025;53(3):745-754. doi:10.1177/03635465241246524
Disclaimer: This content is for educational purposes only and does not substitute for the medical advice of a physician. Always seek the advice of your physician or qualified health provider with any questions you may have regarding a medical condition. Dr. Peng's content reflects his own clinical opinions and does not represent the views of his employers or affiliated hospital systems.
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