Cortisone Shots in the Knee: Relief, Limits and the Repeat-Injection Question

The moment usually arrives on a staircase. The knee that grumbled through last summer’s garden now announces itself on every third step, and someone at work mentions, almost in passing, that a single injection fixed theirs for months. It sounds almost too tidy — one needle, one calm knee.

Cortisone injections have been quieting sore joints since the 1950s, and they remain one of the most common procedures in orthopedic and primary care offices. Yet the conversation around them has grown more careful. Rheumatologists talk about spacing. Trial data hints that the benefit is shorter than most patients expect, and that stacking injections year after year may carry a quiet cost.

So before you roll up a pant leg, it helps to know what the needle can genuinely do, what it cannot, and why the question that matters most is rarely the first shot — it’s the fourth.

What does a cortisone shot in the knee actually do?

The injection places a synthetic corticosteroid — a lab-made cousin of cortisol, the anti-inflammatory hormone your adrenal glands produce — directly inside the joint capsule. Once there, it dials down the immune signaling that drives swelling, warmth, and the ache of an irritated synovium, the thin membrane lining the joint. Because the medication sits where the inflammation lives, a small amount can do what a much larger systemic amount would struggle to accomplish, according to Mayo Clinic.

Most clinicians mix the steroid with a local anesthetic. That combination explains a pattern patients often find confusing: the knee may feel remarkably good for a few hours (the anesthetic), ache again for a day or two (the anesthetic wearing off, sometimes plus irritation from the injection itself), and then settle as the steroid takes hold.

One distinction is worth underlining. Cortisone treats inflammation — it does not rebuild cartilage, tighten a loose ligament, or reverse osteoarthritis. Think of it as turning down a fire alarm rather than repairing what set it off. That’s not a criticism; a quieter alarm can be exactly what a person needs to sleep, walk, and start the strengthening work that actually changes a knee’s trajectory. It simply means the shot is a symptom tool, and expectations should be set accordingly.

How long does relief from a knee cortisone shot last?

Honest answer: it varies more than almost any other fact about this procedure. The steroid usually begins working within 24 to 72 hours, peaks over the first one to two weeks, and then the durability question opens up. Cleveland Clinic notes that relief commonly lasts several weeks to several months; many orthopedic practices tell patients to hope for roughly six weeks to three months and treat anything longer as a bonus.

Clinical trials back up that modest framing. Pooled studies of knee osteoarthritis consistently show the clearest advantage over placebo in the first few weeks, with the difference shrinking — and often disappearing — by the three-month mark. Some knees respond dramatically for half a year; others feel little change at all. Predicting which knee you have is genuinely difficult, though a visibly swollen, fluid-filled joint tends to respond better than a dry, worn one.

Two practical implications follow. First, judge the shot at the two-week mark, not on day two, when a temporary flare can muddy the picture. Second, keep a simple pain diary — a 0-to-10 rating each evening. If a repeat injection is ever on the table, that record tells you and your clinician whether the first one earned its keep. A shot that bought you ten good weeks argues for itself; one that bought ten good days argues for a different plan.

Is it worth getting a cortisone shot in your knee?

It depends entirely on what you’re buying with it. As a bridge, cortisone can be excellent value. A shot that quiets a flared knee for two months can make physical therapy tolerable, get you through a daughter’s wedding weekend, or restore sleep that pain had been stealing — and better sleep and stronger quadriceps pay dividends long after the steroid is gone.

As a destination, it disappoints. If the plan is simply “shot, wait, shot again,” you’re renting relief on a lease that tends to get shorter with time, while the underlying arthritis continues on its own schedule.

The strongest case for saying yes usually includes several of these:

• A distinct flare — swelling, warmth, sudden worsening — layered on top of baseline arthritis.
• A concrete goal the relief window will serve, such as starting a strengthening program.
• Pain that has already resisted first-line steps like activity modification, ice, and exercise therapy.
• A reason to delay or avoid surgery for now.

The weakest case: mild, stable pain that daily habits could plausibly manage, or a knee that got only fleeting relief from a previous injection. In those situations, the sensible move is often to spend your effort — and your clinician’s — on the alternatives covered later in this article. A good injection decision starts with the question “what will I do with the relief?” rather than “will it hurt?”

What happens during the injection — and does it hurt?

The whole appointment is usually shorter than the paperwork. You’ll sit or lie with the knee slightly bent while the clinician cleans the skin and identifies the entry point, most often beside the kneecap. Some offices use ultrasound to guide the needle; for the knee — a large, accessible joint — experienced hands often place it accurately by feel, though imaging can help in swollen or hard-to-access joints.

If the joint holds excess fluid, the clinician may draw some of it out first through the same needle. This step, called aspiration, frequently brings relief on its own by easing pressure, and the fluid can be sent to a lab if there’s any question about infection or gout.

As for pain: most people describe a quick sting from the skin, then a deep pressure sensation as the medication enters the joint — odd more than agonizing, and over in seconds. The knee may feel full or tight for a few hours. A small bandage, a few minutes of observation, and you walk out under your own power.

Per NHS guidance, you can generally drive yourself home unless the anesthetic has made the leg feel numb or unreliable — worth asking about before you book the appointment, since practices vary in what they inject alongside the steroid.

Should you walk after a cortisone shot in the knee?

Yes — normal walking is not only allowed after a knee injection, it’s expected. You’ll walk out of the office, and ordinary daily movement over the following days appears to do no harm. What clinicians actually ask you to avoid is the other end of the spectrum: strenuous loading of the joint for roughly 48 hours. That means no running, jumping, deep squatting, heavy lifting, or long hikes while the medication settles in, a precaution Mayo Clinic includes in its standard aftercare advice.

The logic is twofold. Vigorous activity may irritate a freshly injected joint, and — more subtly — the local anesthetic can mask pain signals that would normally tell you to back off. A knee that feels bulletproof three hours after a shot is being chemically flattered, not cured, and it’s easy to overdo things in that window.

A reasonable timeline looks like this: day of the shot, walk as needed but keep it light and elevate the leg when resting; days one and two, resume normal errands and gentle motion, using ice for ten to fifteen minutes at a time if the joint aches; day three onward, gradually return to your usual exercise, letting comfort set the pace. If you’re in physical therapy, tell your therapist the injection date — most will adjust that week’s session rather than cancel it. Motion, in moderation, is a friend to almost every knee.

Why does the knee sometimes hurt more first? The cortisone flare

A minority of patients get a surprise in the first 24 to 48 hours: the knee hurts more than it did before the appointment. This is the well-documented “cortisone flare,” and while it feels like something went wrong, it usually means nothing of the sort.

The prevailing explanation is mechanical. Some corticosteroid preparations form microscopic crystals inside the joint, and until those crystals dissolve, they can irritate the synovial lining — briefly mimicking the very inflammation the shot was sent to quiet. The injection itself, a needle passing through skin and capsule, contributes its own short-lived soreness.

The flare has a signature worth memorizing, because it separates a nuisance from a red flag:

• It starts within a day or two of the injection, not later.
• It stays in the knee rather than spreading up or down the leg.
• It improves steadily and is typically gone within 48 hours, occasionally 72.
• It responds to ice and rest, and it does not come with fever or chills.

Escalating pain beyond that window — especially with warmth, spreading redness, or feeling generally unwell — belongs in the “call your doctor now” category discussed later, because it can signal the rare but serious complication of joint infection. The flare and the infection can look similar on day one; time and temperature tell them apart. When in doubt, call. No clinician minds a cautious phone call after a joint injection.

What side effects should you actually expect?

For a single, well-placed knee injection, the honest risk profile is reassuring but not empty. Beyond the temporary flare, the effects fall into two buckets: local and body-wide.

Locally, the skin around the injection site can thin over time, and people with darker skin may notice a patch of lightening where pigment cells are affected — usually subtle, sometimes permanent, and more likely with repeated injections in the same spot. Cleveland Clinic also lists temporary bruising and a small risk of bleeding into the joint, which is why patients on blood thinners should mention it beforehand.

Systemically, some of the steroid does escape into circulation. The most common consequences over the following days include facial flushing and warmth (more frequent in women), a night or two of restless sleep or jitteriness, and — importantly for people with diabetes — a rise in blood sugar that can last from a few days to about a week. Menstrual changes for a cycle or two have also been reported.

Then there are the rare events that deserve respect rather than fear: joint infection, estimated in published series at only a few cases per tens of thousands of injections, and allergic reactions, which are similarly uncommon. Weakening of nearby tendon tissue is a documented concern with soft-tissue injections, which is one reason clinicians are choosier about where and how often they inject. None of this should scare a good candidate away; all of it belongs in the conversation before the needle comes out.

Why do some doctors not like to give cortisone shots?

Not out of stinginess — out of data. The hesitation you may sense from a rheumatologist or sports medicine physician traces largely to research on what repeated injections do to cartilage.

The study most often cited is a randomized trial published in JAMA in 2017. Researchers assigned 140 people with knee osteoarthritis to receive an injection every twelve weeks for two years — half got a corticosteroid, half got sterile saline. Two findings landed hard. The steroid group lost measurably more cartilage volume on MRI over those two years. And their pain scores were no better than the saline group’s. More cartilage cost, no pain benefit — for that aggressive every-three-months schedule, at least.

A few caveats keep this from being a verdict on all cortisone shots. The trial tested scheduled, frequent injections in everyone, not occasional shots given for genuine flares. The cartilage difference, while real, was modest, and its long-term clinical meaning is still debated. Observational studies have raised similar concerns about accelerated arthritis in heavily injected knees, but observational data can’t fully separate cause from effect — worse knees get more shots.

Still, the direction of the evidence has changed practice. Many physicians now treat cortisone as a targeted tool for flares rather than a standing appointment, and they watch the calendar. That caution isn’t reluctance to help you. It’s an attempt to make sure this year’s relief doesn’t quietly borrow against next year’s knee.

How many cortisone shots can you have in one knee?

There is no biologically proven ceiling — no trial has established that shot number five is safe and shot number six is not. What exists instead is a widely shared convention, and it’s worth understanding the reasoning behind it.

Most clinicians, echoed by Mayo Clinic’s guidance, space corticosteroid injections at least six weeks apart at an absolute minimum, more commonly three months, and limit a single joint to roughly three or four injections per year. The three-month spacing exists partly because that’s how long benefit can plausibly last, and partly because the cartilage research described above studied — and raised concerns about — the every-twelve-weeks schedule sustained over years.

The smarter question than “how many can I have?” is “what is each one telling us?” A useful pattern to watch:

• If a shot delivers three or more months of meaningful relief, an occasional repeat is generally considered reasonable.
• If relief shrinks with each injection — three months, then six weeks, then a fortnight — the joint is signaling that the strategy is losing traction.
• If a shot delivers under six weeks of relief, many specialists treat that as a cue to change course rather than reload.

Diminishing returns matter for another reason: a knee that no longer responds to cortisone may be approaching the point where a surgical conversation is more honest than another injection. Repeat shots close to a planned knee replacement also raise infection concerns, so surgeons typically want a gap of several months between the last injection and the operation.

Who benefits most from a knee injection — and who benefits least?

Cortisone is an anti-inflammatory, so the knees it helps most are the ones where inflammation is doing the shouting. A joint that is visibly swollen, warm, or carrying extra fluid — the classic flared osteoarthritic knee, or inflammatory arthritis such as gout or rheumatoid disease under a specialist’s direction — tends to respond best. If the clinician draws fluid off before injecting, that’s often a sign you’re in the better-responding group.

At the other end sit knees where the problem is predominantly structural. Advanced, so-called bone-on-bone osteoarthritis has less inflamed tissue for the steroid to calm and more mechanical grinding it cannot touch. These knees can still get a few weeks of relief, but expectations should be modest, and the injection is more of a stopgap while bigger decisions get made.

Purely mechanical pain — a locking sensation from a displaced meniscal fragment, instability from a ligament injury, pain only under specific loads — responds unpredictably, because the needle addresses chemistry, not architecture.

Two other factors shape the calculus. People with diabetes can absolutely receive cortisone, but the several-day blood sugar rise means glucose control and timing deserve a conversation first. And anyone with signs of possible joint infection, or an infection anywhere in the body at the time, should not be injected until that’s resolved — suppressing the immune response inside an infected joint is the one scenario every guideline agrees to avoid.

What is better than cortisone for knee pain?

“Better” depends on the yardstick. For speed, nothing in the non-surgical toolkit beats cortisone. For durability, almost everything else does — including one option that costs nothing and has the strongest evidence base of all.

Option	What the evidence shows	Typical relief window
Cortisone injection	Fast, reliable short-term relief; benefit usually fades within weeks to months	Roughly 6 weeks to 3 months
Exercise therapy / physical therapy	Strongest long-term evidence for knee osteoarthritis; strengthens muscles that unload the joint	Months to years, sustained with practice
Weight management (when applicable)	Each pound lost removes roughly four pounds of load per step; consistently improves pain and function	Long-term
Gel injections (hyaluronic acid)	Mixed trial results; some people report months of relief, major guidelines are lukewarm	Highly variable; often several months when it works
Platelet-rich plasma (PRP)	Promising in some studies, inconsistent in others; usually not covered by insurance	Uncertain; research ongoing
Topical anti-inflammatory gels, bracing, walking aids	Modest but real benefit with minimal risk	While in use

The unglamorous truth: structured exercise — particularly quadriceps and hip strengthening — is the intervention guidelines rank first for knee osteoarthritis, because stronger muscles genuinely change how force moves through the joint. The most effective real-world strategy is often a combination: a cortisone shot to open a window of comfort, then exercise therapy climbing through it. The shot fades. The strength doesn’t have to.

What should you do in the first 48 hours after the shot?

The first two days are mostly about restraint and observation. Here’s a schedule that mirrors what most clinics hand out, minus the tiny font.

Day of the injection. Walk normally but keep activity light. Ice the knee for ten to fifteen minutes at a time, a few times through the evening, with a thin towel between skin and ice. Keep the small bandage on until bedtime and the site clean and dry; a shower is fine, but skip baths, hot tubs, and pools for a day or two while the puncture seals. Remember the anesthetic warning: if the knee feels suspiciously wonderful tonight, that’s the numbing agent talking, not healing.

Days one and two. Resume regular daily movement, but hold off on running, jumping, heavy lifting, and deep squats. Some soreness — even a temporary uptick in pain — is common; ice and elevation handle most of it. If you have diabetes, check your blood sugar more often than usual for the next several days and follow whatever plan you agreed on with your care team, since readings can run high for up to a week.

Ongoing. Start that pain diary. A single nightly number, kept for a couple of months, is the most useful piece of data you can bring to the follow-up conversation — it turns “I think it helped” into “it gave me nine good weeks,” which is exactly the information the repeat-injection decision hinges on.

When should you see a doctor after a cortisone shot?

Serious complications are rare, but the one that matters most — infection inside the joint — is a genuine emergency when it happens, and the early hours count. Contact your clinician promptly, or seek urgent care, if you notice any of the following after a knee injection:

• Pain that keeps escalating beyond 48 hours instead of easing, or pain severe enough that you cannot bear weight.
• Fever, chills, or feeling generally unwell in the days after the shot.
• Redness that spreads outward from the injection site, or a knee that becomes increasingly hot and swollen.
• Drainage, pus, or reopening of the puncture site.
• Signs of an allergic reaction — hives, facial swelling, or trouble breathing — which warrant emergency care immediately.

The tricky part is that a benign cortisone flare and an early joint infection can look alike on the first day. The trajectory separates them: a flare peaks quickly and then improves; an infection worsens, often bringing fever along. If your knee is trending the wrong way at the 48-hour mark, do not wait it out.

Separately, book a routine (non-urgent) visit if the injection simply didn’t work, if relief faded within a few weeks, or if you’re noticing new symptoms like locking, giving way, or night pain that wakes you. Those patterns don’t mean anything went wrong with the shot — they mean the knee is asking for a fuller evaluation, and possibly a different plan.

Questions worth asking before you say yes

A five-minute conversation before the injection often does more for your outcome than anything that happens after it. Consider bringing these to the appointment:

• “What exactly are we treating?” An inflamed osteoarthritic flare, a fluid-filled joint, and mechanical pain from a torn meniscus are three different problems with three different odds of responding.
• “Will you draw off fluid first?” Aspiration can relieve pressure, aid diagnosis, and hints that inflammation — cortisone’s actual target — is present.
• “What’s the plan when this wears off?” The best answer names something other than another shot: a strengthening program, weight-management support, a follow-up visit with defined next steps.
• “How will we judge whether it worked?” Agree on a timeframe and a measure — walking distance, stairs, sleep — so the next decision rests on evidence rather than impression.
• “How does this fit my other conditions?” Diabetes, blood thinners, upcoming surgery, or a recent infection all change the risk calculation, and all are easy to address when raised in advance.

One final reframe, offered with an editor’s bias toward the evidence: the cortisone shot is a fine supporting actor and a poor lead. Used occasionally, for the right knee, with a plan attached, it buys comfortable weeks that can be invested in the things that genuinely bend the curve of knee pain. Used as the whole strategy, it’s a series of shrinking loans. The needle is the easy part. What you do with the quiet it buys is the treatment.

Frequently asked questions

Should you walk after a cortisone shot in the knee?

Yes — normal walking is expected and safe right after a knee cortisone shot. What you should avoid for roughly 48 hours is strenuous loading: running, jumping, deep squats, and heavy lifting. The local anesthetic can make the knee feel deceptively good for a few hours, so resist the urge to test it. Gentle daily movement, ice for aches, and a gradual return to exercise from day three onward is the standard approach.

Is it worth getting a cortisone shot in your knee?

It can be, if you have a clear goal for the relief window. Cortisone works best as a bridge — quieting a flared, swollen knee so you can sleep, function, and start physical therapy that builds lasting improvement. Trials show the benefit is strongest in the first few weeks and often fades by three months. As a standalone, repeated strategy, it tends to deliver diminishing returns, so pair it with a longer-term plan.

How long does a cortisone shot last in the knee?

Most people get somewhere between six weeks and three months of meaningful relief, though the range is wide — some knees respond for six months, others barely at all. The steroid starts working within one to three days and peaks over the first two weeks. Swollen, inflamed joints tend to respond better than dry, mechanically worn ones. Keeping a simple nightly pain rating helps you and your clinician judge whether a repeat is worthwhile.

Why do doctors not like to give cortisone shots?

Because repeated injections may carry a cartilage cost. A 2017 randomized trial in JAMA found that people who received a corticosteroid injection every three months for two years lost more knee cartilage on MRI than those receiving saline, with no better pain control. The finding applies to that frequent schedule, not occasional shots, but it shifted practice: many physicians now use cortisone selectively for flares and watch the calendar between injections.

What is better than cortisone for knee pain?

For lasting results, structured exercise therapy has the strongest evidence for knee osteoarthritis — strengthening the quadriceps and hips genuinely changes joint loading, and weight management, where applicable, compounds the benefit. Cortisone remains the fastest option. Gel injections show mixed trial results, and platelet-rich plasma is promising but inconsistent in studies. The most effective approach is often combined: a shot to open a window of comfort, then strengthening work through it.

How many cortisone shots can you have in one knee?

There’s no proven biological limit, but standard practice caps one joint at roughly three or four injections per year, spaced at least three months apart. The more telling number is how long each shot lasts: three-plus months of relief supports an occasional repeat, while shrinking benefit — or under six weeks of relief — signals it’s time for a different strategy. Repeated shots also complicate timing if knee replacement surgery is on the horizon.

Does a cortisone shot in the knee hurt?

Less than most people fear. Expect a quick sting as the needle passes through skin, then a deep pressure or fullness as the medication enters the joint — over in seconds. Many injections include a local anesthetic, so the knee may feel unusually good for a few hours before a day or two of mild soreness. A minority experience a ‘cortisone flare,’ a temporary pain increase in the first 48 hours that ice usually manages.

Can a cortisone shot raise blood sugar?

Yes. Some of the steroid enters the bloodstream, and in people with diabetes, glucose readings can run noticeably higher for several days to about a week after a joint injection. This doesn’t rule out the shot, but it does mean checking blood sugar more frequently afterward and discussing timing and monitoring with your care team beforehand. People without diabetes typically notice no meaningful change.

What is a cortisone flare and how long does it last?

A cortisone flare is a temporary increase in knee pain during the first 24 to 48 hours after injection, thought to occur when microscopic steroid crystals briefly irritate the joint lining before dissolving. It affects a minority of patients, stays localized to the knee, comes without fever, and improves steadily with ice and rest — usually resolving within two days. Pain that escalates beyond 48 hours or arrives with fever needs prompt medical evaluation instead.

Can cortisone shots damage the knee?

A single, well-spaced injection is considered low-risk. The concern centers on frequency: trial evidence links injections every three months over years to modestly greater cartilage loss, and observational studies raise similar flags for heavily injected knees. Local effects like skin thinning or lightening can occur at the injection site, and joint infection — though estimated at only a few cases per tens of thousands of injections — is the rare serious risk. Sensible spacing manages most of these concerns.

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.