Several newer knee injections have emerged in recent years, but the one generating the most attention is an extended-release corticosteroid that uses microsphere technology to deliver medication over roughly three months instead of the few weeks a traditional cortisone shot provides. Beyond that, updated single-shot hyaluronic acid formulations, platelet-rich plasma (PRP), and genicular nerve blocks have all expanded the menu of options for people with knee osteoarthritis or chronic knee pain.
Each injection works differently, lasts a different amount of time, and carries its own trade-offs. Here’s what you need to know about the main options available now.
Extended-Release Corticosteroid Injections
The most notable newer entry is an FDA-approved formulation that embeds the steroid triamcinolone acetonide inside tiny biodegradable microspheres. Once injected into the knee joint, these microspheres dissolve gradually, releasing the medication into the surrounding tissue over about three months rather than all at once. Traditional cortisone shots deliver the full dose immediately, which is why their pain relief often fades within a few weeks.
The extended-release version was designed specifically for knee osteoarthritis. Because the drug stays local to the joint longer, blood sugar spikes and other systemic side effects that sometimes follow a standard steroid injection tend to be smaller and shorter-lived. That said, it is still a corticosteroid, and the structural risks described below apply.
The Cartilage Concern With Steroids
Research published in 2025 by the Radiological Society of North America found that corticosteroid injections, even a single one, were associated with significantly greater structural damage in the knee joint over two years compared to hyaluronic acid injections. Corticosteroids reduce inflammation effectively but also impair the repair mechanisms of cartilage and can inhibit the production of the matrix that holds cartilage together. Over time, this weakens cartilage and can actually accelerate osteoarthritis progression. There is also evidence linking steroid injections to changes in the bone just beneath the cartilage and an increased risk of stress fractures in that area.
Hyaluronic acid injections, by contrast, did not show this damage. Patients who received them actually had reduced joint deterioration after injection. This finding has prompted many orthopedic specialists to reconsider how often they recommend corticosteroid shots, even the newer extended-release version, for patients with mild to moderate arthritis who still have cartilage worth preserving.
Single-Shot Hyaluronic Acid Injections
Hyaluronic acid (sometimes called viscosupplementation) mimics the natural lubricating fluid inside your knee. Older versions required three to five weekly injections. Newer single-shot formulations like Durolane and Monovisc deliver the full course in one visit, with manufacturers reporting relief lasting up to six months in roughly 80% of patients.
The main drawback is cost and coverage. Medicare currently does not cover many of these products, and out-of-pocket prices can run around $450 or more per injection. Private insurance coverage varies. When Medicare does cover hyaluronic acid injections, documentation must show the treatment is medically necessary for diagnosed osteoarthritis, not a routine or preventive measure. If ultrasound is used to guide the needle, the medical record needs to justify why the injection site was difficult to access without imaging.
Improvement from hyaluronic acid is not instant. It typically takes one to four weeks before you notice a meaningful reduction in pain and stiffness.
Platelet-Rich Plasma (PRP)
PRP injections use a concentrated portion of your own blood. A small sample is drawn, spun in a centrifuge to separate the platelets and growth factors, and then injected into the knee. The idea is that these growth factors stimulate tissue repair and reduce inflammation from within the joint.
Mayo Clinic physicians report a 60% to 70% chance of success with PRP for knee osteoarthritis, defining success as at least a 50% improvement in pain and function lasting 6 to 12 months. That’s a solid response rate, but it also means roughly one in three patients won’t get meaningful relief. PRP is almost never covered by insurance, and a single treatment typically costs $500 to $1,500 depending on the clinic and region.
PRP is not FDA-approved as a drug. It’s considered an autologous (from your own body) preparation, so clinics can offer it under existing medical practice rules. Quality varies between providers because there is no single standardized protocol for how the blood is processed, how concentrated the platelets should be, or how many injections are ideal.
Genicular Nerve Blocks
This approach targets the problem from a completely different angle. Instead of treating the joint itself, genicular nerve blocks interrupt the pain signals traveling from the knee to the brain. A doctor injects numbing medication near the sensory nerves that surround the knee joint. Three of the four main genicular nerves can be safely targeted; the fourth sits too close to the peroneal nerve (which controls foot movement) to inject without risk.
A nerve block is typically a diagnostic step. If it provides temporary relief, you may be a candidate for a longer-lasting procedure called radiofrequency ablation, which uses heat to disable those same nerves for months at a time. This option is particularly useful for people who aren’t candidates for knee replacement or who want to delay surgery.
What Recovery Looks Like
Most knee injections are quick office procedures that take 5 to 15 minutes. Afterward, you can generally resume normal activities but should avoid anything strenuous or high-impact for at least 48 hours. For the first 24 hours, applying ice wrapped in a cloth for 20 minutes on and 20 minutes off helps manage any soreness at the injection site. Avoid soaking the area in a bath for the first day, though showering the next morning is fine.
Some swelling or mild discomfort at the injection site is normal and usually resolves within a day or two. The timeline for feeling actual pain relief depends on the type of injection: steroid injections often work within a few days, hyaluronic acid takes one to four weeks, and PRP can take several weeks as the growth factors gradually do their work.
Choosing Between Options
The right injection depends on how much cartilage you have left, how severe your pain is, and what you can afford. For people with moderate to advanced osteoarthritis who need quick relief for a specific event or to bridge to surgery, a corticosteroid injection (traditional or extended-release) still works fast. But the evidence on cartilage damage means it’s worth having a direct conversation about how many you’ve already had and whether the short-term benefit is worth the long-term structural cost.
If your arthritis is mild to moderate and you’re trying to preserve joint health, hyaluronic acid or PRP may be better long-term choices. Hyaluronic acid has the advantage of being the only option shown to actually reduce joint deterioration after injection. PRP offers a biological repair approach but comes with more variability in results and no insurance coverage. Genicular nerve blocks are best suited for people whose primary goal is pain management rather than slowing disease progression, especially when surgery isn’t an immediate option.