You've already tried physical therapy, NSAIDs, and probably a cortisone shot or two — and you're not ready (or not eligible) for a knee replacement. Here's how LAOSS pain management specialists decide between a repeat steroid injection and radiofrequency genicular nerve ablation when chronic knee OA pain won't quit.
Cortisone calms the joint for weeks. Ablation quiets the nerves for months.
If you've been living with chronic knee osteoarthritis pain — the kind that hasn't given way to physical therapy, oral medications, or activity modification — there's a decent chance you've already had at least one cortisone injection. Maybe it helped for a couple of months. Maybe it helped less than the time before. And the conversation has started to drift toward knee replacement.
For patients who aren't ready for a total knee replacement, aren't candidates for one (because of age, medical comorbidities, or surgical risk), or simply want to defer the operation as long as possible, there's a middle option that often gets overlooked: radiofrequency genicular nerve ablation.
Cortisone injection delivers a potent anti-inflammatory steroid directly into the knee joint. It calms the inflammatory chemistry driving your pain. It's been the workhorse of nonsurgical knee OA care for decades — fast, cheap, covered, and effective for 4–12 weeks.
Radiofrequency genicular nerve ablation (RFA) is different. Instead of going after inflammation inside the joint, RFA uses radiofrequency energy to interrupt the sensory nerves that carry pain signals from the knee to the brain — specifically the superior medial, superior lateral, and inferior medial genicular nerves. The joint is still arthritic. The nerves that report it to the brain are quieted. Relief lasts 6–12 months in most responders, after which the nerves regrow and the procedure can be repeated.
This page walks through how LAOSS pain management specialists choose between them — honestly, without overselling either option.
A short overview of how image-guided procedures — from joint injections to nerve-targeted treatments — fit into the treatment ladder for knee osteoarthritis pain.
Animations licensed from ViewMedica · Swarm Interactive
Three small sensory nerves — the **superior medial, superior lateral, and inferior medial genicular nerves** — carry most of the pain signal from the front of the knee to the spinal cord and brain. They run in predictable bony locations around the knee, which makes them targetable with ultrasound or fluoroscopic guidance. A cortisone injection puts medication inside the joint to calm inflammation. Radiofrequency ablation places needle probes alongside these specific nerves and heats their tip to roughly 80°C for 90 seconds, creating a controlled lesion that interrupts the pain signal. The joint itself isn't touched. The cartilage damage is unchanged. What changes is how loudly the knee can complain.
There's no universal answer — but the decision usually breaks down along four axes: how long relief needs to last, what came before, what your surgical timeline looks like, and what your insurance will cover.
How long relief needs to last. If you need to function in 48 hours — for work, a family event, travel — cortisone wins on speed. Onset is 24–48 hours, peak relief at 2–4 weeks. If you want one procedure to hold for 6 months or more, ablation is the structural answer. The lesion doesn't fade like a steroid effect; the nerves have to physically regrow before the pain signal returns.
What came before. If cortisone has worked durably and you've only had 1–2 shots, the simplest move is another well-timed injection. If you've used 3–4 cortisone shots in the past year and the benefit is getting shorter each time, we treat that as a signal — the inflammatory model isn't carrying you anymore, and it's time to consider a nerve-targeted approach.
What your surgical timeline looks like. If you and your surgeon have decided knee replacement is happening in the next few months, neither procedure is going to change that. If you're trying to defer TKR for 1–3+ years (you're young, you're active, you're not done with the knee yet, or you're a poor surgical candidate), ablation buys real time. We can repeat the ablation when the nerves grow back, often indefinitely.
Insurance. Both are typically covered, but the path is different. Cortisone is a same-visit decision. Ablation requires prior authorization plus a diagnostic genicular nerve block — a temporary numbing injection that predicts whether the radiofrequency procedure will actually work for you. We don't ablate without that data.
Most patients don't have to pick one and never touch the other — these procedures often sequence over years of knee OA care. Here's how each path actually looks.
When pain is acute, inflammatory, or you're early in the knee OA journey — cortisone is usually the right first move.
When durability matters more than speed, or when cortisone has stopped pulling its weight — ablation is the structural answer.
Both procedures are typically covered when conservative care has failed — but the authorization process is very different.
Knee cortisone injection is a standard orthopedic service covered by virtually every commercial plan and Medicare. Often performed at the same visit as your evaluation.
Radiofrequency genicular nerve ablation is covered by most commercial plans and Medicare when conservative care has failed and a diagnostic block has confirmed candidacy.
Onset and duration are where these two procedures diverge most. Knowing the curve helps you plan around real life.
The local anesthetic gives you a few hours of immediate relief. The steroid kicks in over 24–48 hours and runs its course over weeks.
Ablation works by interrupting nerve signal, not by drug pharmacology. The benefit builds over 2–4 weeks and holds for the better part of a year.
We won't oversell ablation, and we won't dismiss cortisone. Here's the honest read on the published literature for chronic knee OA.
Decades of trials support cortisone for short-term knee OA pain. The catch is durability and what repeated use does to the joint.
Multiple randomized trials show radiofrequency genicular nerve ablation outperforms repeat cortisone at 6 and 12 months — when patients are selected with a diagnostic block.
These checklists are a starting point — the final call comes at your evaluation, with imaging and exam findings in front of us.
Cortisone is usually the right first move when symptoms are acute, inflammatory, and you need to function quickly.
Ablation is the better call when cortisone has plateaued, you're not ready for TKR, and you want one procedure to hold for months.
Cortisone recovery is measured in hours. Ablation recovery is measured in days to weeks. Both let you drive yourself home the same day.
Cortisone is an in-and-out office procedure. Most patients walk out and resume normal activity the same day.
Ablation creates small thermal lesions on the genicular nerves — expect 3–7 days of soreness around the probe sites as the lesions mature.
Physical therapy pairs with both procedures. With cortisone, PT works during the inflammation-quiet window. With ablation, PT happens during a longer pain-free window — and the goal is to actually rebuild strength.
Most patients we see for genicular nerve ablation have already had cortisone injections — sometimes for years. That's not a failure of cortisone. That's the natural arc of progressive knee osteoarthritis: PT and oral medications first, then cortisone when those plateau, then a stronger interventional option when cortisone plateaus.
A common LAOSS sequence for a 58-year-old with bilateral knee OA who isn't ready for replacement:
We also occasionally use a single cortisone shot inside an ablation course — for example, if a patient develops an acute inflammatory flare 4 months into a successful ablation. The procedures don't fight each other; they target different mechanisms in the same knee.
And there are situations where the answer is neither yet — for early arthritis, structured PT and weight management often outperform either procedure. We'll tell you that too.
Both procedures are well-tolerated when delivered by experienced specialists under image guidance — but the risk profiles are different.
Cortisone is one of the most-studied orthopedic interventions. Risks are well-characterized and most are short-lived.
Genicular nerve ablation is a low-complication procedure in experienced hands — most of the risks are local and short-lived.
Both cortisone injections and genicular nerve ablation at LAOSS are performed by board-certified pain management physicians with fellowship training in image-guided interventional procedures. Every ablation candidate gets a diagnostic genicular nerve block first — performed by the same physician who will do the ablation — so the person reading the diagnostic response is the person doing the procedure. No hand-offs, no marketing-driven packages, no ablation without confirmed candidacy.
Dr. Acosta saved me from spine surgery. I came in convinced I was going to need an operation. He laid out a non-surgical plan that's been working. So thankful.
Book a visit at any of our eight Los Angeles-area offices. We'll examine the knee, review your imaging, and tell you straight whether another cortisone shot, a diagnostic block followed by ablation, regenerative options, or a surgical referral is the right next step.
