What patients ask us most
- Which one actually works better for knee arthritis?
- Why isn't PRP covered by my insurance?
- How fast does each one work — and how long does it last?
- Can I do both, and in what order?
- Will PRP help me avoid knee replacement?
PRP vs Cortisone for knee pain.
Both injections are common, both work — but for different reasons, on different timelines, at very different prices. Here's how LAOSS specialists decide which one fits your knee, tendon, or joint, and when it makes sense to use both.
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Two injections, two jobs.
Cortisone calms inflammation. PRP signals healing.
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What sets LAOSS apart
- Honest evidence framing — neither overselling nor dismissing either option
- Ultrasound-guided technique on every injection
- Same- or next-day appointments at eight LA-area offices
- Board-certified pain management physicians, not generalists
Key takeaways
- Cortisone is fast, cheap, and insurance-covered — strongest evidence for short-term pain relief (4–12 weeks). It calms inflammation but doesn't heal tissue.
- PRP is slower, expensive, and usually not covered ($500–$2,000 per injection) — but it stimulates actual tissue healing and the benefit can last longer.
- For knee osteoarthritis, cortisone is often the right first move when pain is acute. PRP is the better long-game option for mild-to-moderate OA in active patients.
- Cortisone is the clear winner for tennis elbow and plantar fasciitis at 6 weeks. PRP is the clear winner at 6 months. Same conditions, different timelines.
- Avoid cortisone in the 3 months before a planned knee replacement. Stop NSAIDs 1–2 weeks before any PRP injection.
Overview
PRP vs cortisone: same needle, different jobs.
On the surface, PRP and cortisone injections look identical — both are in-office shots, both go into the joint or tendon, both are part of a conservative orthopedic plan. But they do completely different things to the tissue.
Corticosteroid (cortisone) injections deliver a potent anti-inflammatory steroid (typically triamcinolone or methylprednisolone) mixed with a local anesthetic. The mechanism is well-understood — the steroid suppresses the inflammatory cascade that's driving your pain. Relief typically starts within 24–48 hours, peaks at 2–4 weeks, and lasts somewhere between 4 weeks and 6 months depending on the joint and the underlying problem.
Platelet-rich plasma (PRP) injections use the growth factors from your own blood to trigger tissue repair. A small blood draw is spun in a centrifuge to concentrate platelets, which release signals that recruit healing cells to the injured tendon or joint. You don't feel better for 2–6 weeks — and peak benefit often lands at 3–6 months. The goal isn't to silence inflammation; it's to help the tissue actually remodel.
At LAOSS we use both. The question we answer at every visit isn't "PRP or cortisone" in the abstract — it's which one (or both, in sequence) fits your diagnosis, your timeline, your budget, and your activity goals.
Patient education
Watch: How injections treat joint pain
Whether it's cortisone to calm inflammation or PRP to stimulate healing, image-guided joint injections are a cornerstone of non-surgical orthopedic care. This short video walks through what to expect.
Animations licensed from ViewMedica · Swarm Interactive
Cortisone targets the inflammatory soup in the joint. PRP targets the cells doing (or failing at) the healing.
Mechanism
What's actually happening in your joint.
In an arthritic knee, the cartilage is worn, the synovium (joint lining) is inflamed, and inflammatory cytokines flood the joint — that's most of what you feel as pain. Cortisone shuts that inflammatory signal off; you feel better, fast, but the underlying cartilage and tendon damage isn't directly addressed. PRP delivers concentrated growth factors that recruit healing cells to the damaged tissue — slower, but aimed at repair, not just symptom suppression. Two different leverage points on the same problem.
When each option makes sense
Picking the right tool for the pain.
Symptoms
Common symptoms
- Acute flare of knee OA — cortisone for fast relief while you start PT
- Chronic, plateaued knee OA in an active patient — PRP for tissue-level effect
- Tennis elbow (lateral epicondylitis) — cortisone short-term, PRP long-term
- Plantar fasciitis past 3 months of PT — PRP outperforms cortisone at 6 months
- Rotator cuff tendinopathy with impingement — cortisone often first
- Patellar tendinopathy (jumper's knee) — PRP, not cortisone (steroid weakens tendon)
- Pre-op pain control before knee replacement — cortisone (but not within 3 months of surgery)
- Athlete who can't accept tendon weakening — PRP, never cortisone in the tendon
Causes
Common causes
- Inflammation is the dominant driver — cortisone is the leverage point
- Tissue degeneration is the dominant driver — PRP is the leverage point
- You need to function in 48 hours (work, wedding, travel) — cortisone
- You're trying to delay or avoid surgery for 6+ months — PRP
- Cost and insurance are the constraint — cortisone wins almost every time
Decision framework
How we choose at LAOSS.
There's no universal answer — but the decision usually breaks down along four axes: diagnosis, timeline, cost, and what comes next.
Diagnosis. Cortisone is a strong tool for inflammatory or arthritic pain — synovitis, knee OA flares, bursitis, impingement. It is a poor (and sometimes harmful) tool for tendon problems, because repeated steroid exposure weakens tendon tissue. For tendinopathy — tennis elbow, patellar tendon, Achilles, plantar fascia — PRP is almost always the better long-term call.
Timeline. Cortisone works fast (24–48 hours), peaks at a few weeks, and fades by 2–3 months in most patients. PRP doesn't really kick in until week 4–6, peaks at 3–6 months, and the benefit can last a year or more for the patients who respond.
Cost. Cortisone is covered by virtually every insurance plan — expect a $30–$100 copay. PRP is usually not covered. Out-of-pocket runs $500–$2,000 per injection depending on the site and whether ultrasound guidance is used, and most courses are 1–3 injections.
What comes next. If you're heading toward a knee replacement, you need to stop cortisone at least 3 months before surgery (it raises infection risk) — and PRP isn't going to change the surgical math. If you're trying to stay out of the OR for another 1–3 years, PRP is the more strategic move.
Treatment paths
Cortisone-first vs PRP-first.
Most patients don't have to pick one and never touch the other. Here's how we sequence them based on which path fits your situation.
Conservative care
Step 1Cortisone-first path
When pain is acute, function is collapsing, or cost is a hard constraint — cortisone moves first.
- Acute knee OA flare with severe pain and swelling
- Need to function for work, travel, or family event in days, not weeks
- Strong inflammatory component on exam and imaging
- Insurance-only budget — cortisone $30–$100 copay, PRP not covered
- Pre-surgical pain bridge (but not within 3 months of joint replacement)
- Bursitis, synovitis, or impingement where inflammation is the main driver
Surgical care
When neededPRP-first path
When tissue healing matters more than fast symptom suppression — PRP moves first.
- Tennis elbow, patellar tendon, Achilles, plantar fascia (no steroid in tendons)
- Mild-to-moderate knee OA in an active patient trying to delay replacement
- Athletes who can't accept steroid-induced tissue weakening
- Patients who've already used 2–3 cortisone shots in the past year
- Partial rotator cuff or partial ligament tears that haven't healed with PT
- Long-game orientation — willing to wait 6 weeks for benefit that may last a year
Cost & coverage
What each one actually costs.
Cost is often the deciding factor — and unlike a lot of clinics, we quote the number before you commit.
Covered
Cortisone — insurance-covered
Cortisone injection is a covered orthopedic service under virtually every commercial plan and Medicare. Your cost is typically just the copay for a specialist visit and a small injection fee.
- Typical out-of-pocket: $30–$100 copay (varies by plan)
- Covered by commercial insurance, Medicare, and most Medi-Cal plans
- Same-day in-office procedure, no separate scheduling
- Usually limited to 3–4 injections per joint per year
- Ultrasound or fluoroscopic guidance often covered when medically necessary
Self-pay
PRP — self-pay
Most insurance plans classify PRP as investigational for orthopedic indications. We tell you the exact number before you book — no surprise billing.
- Typical out-of-pocket: $500–$2,000 per injection
- Most courses are 1–3 injections, spaced 4–6 weeks apart
- Total course cost typically $1,000–$5,000 depending on indication
- HSA/FSA generally eligible — bring documentation
- We quote the exact number at evaluation, before you commit
Timeline
How fast — and how long.
Onset and duration are where these two diverge the most. Knowing the curve helps you plan around real life.
Fast
Cortisone — fast on, fast off
The local anesthetic in the mix gives you a few hours of immediate relief. The steroid kicks in over 24–48 hours and runs its course over weeks to a few months.
- Immediate (hours): anesthetic effect, then it wears off
- Day 1–2: steroid effect begins, inflammation drops
- Weeks 2–4: peak benefit for most patients
- Months 2–4: benefit typically fading
- Repeat: not more often than every 3–4 months, usually 3–4 per year max
Durable
PRP — slow on, slow off
PRP works on tissue biology, not pharmacology. The timeline is measured in weeks of remodeling, not hours of pain relief.
- Days 0–7: soreness at the injection site (expected, not a complication)
- Weeks 2–4: first meaningful improvement for most responders
- Weeks 6–12: full benefit for most who respond
- Months 6–12: peak benefit, can persist a year or more
- Repeat: second injection at 6 weeks if response is partial; up to 3 per course
Evidence
What the data actually says.
We won't oversell PRP, and we won't dismiss cortisone. Here's the honest read on the orthopedic literature, by condition.
Short-term
Cortisone — strong short-term data
Decades of trials support cortisone for short-term pain relief in inflammatory and arthritic joint conditions. The catch is durability and tissue effects with repeat use.
- Strong evidence for short-term knee OA pain relief (4–12 weeks)
- Strong evidence for shoulder impingement, hip bursitis, trigger finger
- Effective for tennis elbow at 6 weeks — but underperforms PRP at 6 months
- Repeated knee injections (>3–4/year) associated with cartilage loss in OA
- Avoid in 3 months before joint replacement (infection risk)
Site-specific
PRP — evidence varies by site
PRP isn't a blanket good idea — it's a strong tool for specific indications. We tell you which camp your diagnosis falls into.
- Strong evidence: lateral epicondylitis (tennis elbow), patellar tendinopathy
- Moderate evidence: mild-to-moderate knee OA, plantar fasciitis, Achilles
- Weaker evidence: rotator cuff tendinopathy, hip OA
- Not supported: full-thickness tears, end-stage (bone-on-bone) arthritis
- Even for well-supported uses, ~20–30% of patients see limited benefit
Candidacy
Which one fits me?
These checklists are a starting point — the final call comes at your evaluation, with imaging and exam findings in front of us.
Cortisone
You're a cortisone candidate if
Cortisone is most often the right first move when symptoms are acute, inflammatory, and you need to function quickly.
- Acute knee OA flare with significant swelling or pain
- Inflammatory joint condition (bursitis, synovitis, impingement)
- You need fast functional relief — 48 hours, not 6 weeks
- Cost or insurance is a constraint and PRP isn't realistic
- You haven't already had multiple steroid injections this year
- You're not within 3 months of a planned joint replacement
PRP
You're a PRP candidate if
PRP is the better call when tissue healing matters more than fast symptom suppression — and when steroid would be the wrong physiologic tool.
- Chronic tendinopathy (tennis elbow, patellar, Achilles, plantar fascia)
- Mild-to-moderate knee OA, active patient, delaying replacement
- Already used 2–3 steroid shots without durable relief
- Athlete or laborer who can't accept tendon weakening
- Imaging shows partial tear or tendinopathy, not bone-on-bone
- You can budget for self-pay and stop NSAIDs 1–2 weeks before
ImportantAvoid cortisone in the 3 months before a planned joint replacement (raises infection risk). PRP requires stopping NSAIDs (ibuprofen, naproxen, aspirin) 5–7 days before and for 2 weeks after — NSAIDs blunt the healing response. Acetaminophen is fine for both.
Recovery
What each recovery looks like.
Recovery timelines diverge sharply — cortisone is measured in hours and days, PRP in weeks and months.
01Cortisone · Days 0–14
Fast onset, normal activity
Cortisone is an in-and-out office procedure. Most patients walk out and resume normal activity the same day.
- Mild soreness for 24–48 hours at the injection site (normal)
- Resume normal activity the same day — no restrictions
- Pain relief typically starts within 24–48 hours
- Ice and acetaminophen if injection-site soreness flares
02PRP · Days 0–14
Expected soreness, slow build
PRP triggers an inflammatory healing response. You'll feel sore for 2–4 days — that's the response working, not a complication.
- Soreness at the injection site for 2–4 days (expected)
- Relative rest from the inciting activity for 48–72 hours
- Avoid NSAIDs for 2 weeks — they blunt the healing signal
- Acetaminophen is fine; normal walking from day 1
03Weeks 2 to Months 6+
Coordinated PT either way
PT pairs with both injections. With cortisone, PT happens while the steroid is calming inflammation. With PRP, PT is what locks in tissue remodeling.
- Cortisone: PT to capitalize on the pain-free window (weeks 1–8)
- PRP: progressive loading and eccentric work (weeks 2–12)
- Coordinated through your in-network provider
- Re-evaluation at 6–12 weeks to decide on repeat or pivot
When to use both
The combined approach.
It's not unusual to use both — just not on the same day and not in the same way.
A common pattern at LAOSS for knee osteoarthritis: cortisone now to break a severe pain cycle, PRP later to address the underlying tissue. The steroid buys you 6–12 weeks of functional relief while you start physical therapy. Then, once the acute flare is calm, PRP can be considered for the longer-term tissue-level work. We typically wait at least 6–12 weeks between a cortisone injection and a PRP injection in the same joint, because residual steroid in the tissue can blunt the PRP healing response.
For tendinopathies, we generally do not stack them. Repeat steroid exposure weakens tendon tissue, so for tennis elbow, patellar tendon, Achilles, and plantar fascia, the long-term move is almost always PRP rather than serial cortisone.
And there are situations where the answer is neither yet — for early arthritis or mild tendinopathy, structured physical therapy, activity modification, and time often outperform either injection. We'll tell you that too.
Risks & considerations
Side-by-side risk profile.
Both injections are well-tolerated when delivered by experienced specialists under image guidance — but the risk profiles are different.
Cortisone
Cortisone considerations
Cortisone is one of the most-studied orthopedic interventions. Risks are well-characterized and most are short-lived.
- Post-injection flare (steroid flare) for 24–48 hours in some patients
- Skin discoloration or subcutaneous fat thinning at the injection site
- Transient blood sugar elevation (notable for diabetics)
- Cartilage thinning with repeated knee injections (>3–4/year)
- Tendon weakening if injected into or near a tendon
- Increased infection risk if performed within 3 months of joint replacement
PRP
PRP considerations
Because PRP uses your own blood, allergic reaction is essentially nonexistent. The real risks are small — the bigger consideration is cost and response variability.
- Soreness at the injection site for 2–4 days (expected response)
- Bleeding or bruising at the draw or injection site
- Infection at the injection site (rare with sterile technique)
- ~20–30% of patients see limited benefit even for well-supported uses
- Not appropriate for active infection, platelet disorders, or active cancer
- Stop NSAIDs 5–7 days before, avoid for 2 weeks after
Your care team
Meet the injection specialists at LAOSS.
Both cortisone and PRP at LAOSS are performed by board-certified pain management physicians with deep training in ultrasound- and fluoroscopy-guided injection technique. PRP uses our in-house centrifuge protocol — the same physician who does your diagnostic ultrasound prepares the sample and performs the injection. No hand-offs to ancillary staff, no marketing-driven "packages." The person diagnosing is the person treating.
Patient reviews
What patients say about us.
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FAQ
PRP vs cortisone — common questions
- It depends on the timeframe and the stage of arthritis. For short-term pain relief in an acute flare (4–12 weeks), cortisone has the strongest evidence and works fastest. For mild-to-moderate knee osteoarthritis where you're trying to stay active and delay knee replacement, PRP has better data at 6–12 months in published trials — particularly in patients under 65 with mild-to-moderate disease. For bone-on-bone (end-stage) arthritis, neither injection meaningfully changes the trajectory; the conversation shifts to joint replacement. At LAOSS we frequently use cortisone first to break a pain cycle, then transition to PRP for the longer game.
- Yes, and many patients do — but not on the same day and not for tendon conditions. For knee OA, a common pattern is cortisone first to calm an acute flare, then PRP 6–12 weeks later for tissue-level work. We wait at least 6 weeks (often longer) between the two, because residual steroid in the tissue can blunt the PRP healing response. For tendinopathies — tennis elbow, patellar tendon, Achilles, plantar fascia — we generally don't combine them, because repeat steroid exposure weakens tendon tissue and works against the PRP.
- Most commercial insurance plans and Medicare classify PRP as investigational for orthopedic indications. Insurers point to variability in PRP preparation methods (different centrifuge protocols, different platelet concentrations) and mixed evidence in some indications as reasons to defer coverage. Cortisone, by contrast, has been a standard-of-care orthopedic intervention for decades with extensive insurance precedent. The practical result: cortisone is a $30–$100 copay; PRP is $500–$2,000 per injection out-of-pocket. We quote the exact PRP cost before you commit — HSA/FSA dollars are generally eligible.
- Cortisone works fast. The local anesthetic in the mix gives you a few hours of immediate relief; the steroid effect kicks in over 24–48 hours and peaks at 2–4 weeks. PRP works slowly. You'll be sore for 2–4 days right after the injection (that's the inflammatory healing response, not a complication), the first meaningful improvement shows up around week 4, and peak benefit usually lands at 3–6 months. If you need to function in 48 hours, cortisone. If you can budget 6 weeks for benefit and want it to last longer, PRP.
- Cortisone is typically limited to 3–4 injections per joint per year, with at least 3 months between shots in the same joint. More frequent steroid exposure has been associated with cartilage thinning in knee osteoarthritis, so we're conservative about repeat use. PRP courses are usually 1–3 injections spaced 4–6 weeks apart — we re-evaluate after each one and only continue if you're responding. If there's no meaningful improvement by 12 weeks after the first PRP injection, we pivot to a different approach rather than chase diminishing returns.
- Sometimes — and we won't pretend otherwise. For patients with mild-to-moderate knee osteoarthritis who are otherwise active and have intact cartilage architecture, PRP can meaningfully reduce pain and delay the timeline to replacement, sometimes by years. For patients with end-stage (bone-on-bone) arthritis, severe deformity, or mechanical symptoms like locking and giving way, PRP generally cannot substitute for surgical replacement. The honest answer at your evaluation depends on your imaging, your exam, your activity level, and your goals. We'll tell you which camp you're in.
- Cortisone has essentially no recovery — most patients resume normal activity the same day. You may feel mild injection-site soreness for 24–48 hours and (in 1–2% of patients) a temporary post-injection flare in the first 2 days, but no restrictions on walking, working, or activity. PRP requires more orchestration: expect 2–4 days of injection-site soreness, relative rest from the inciting activity for 48–72 hours, no NSAIDs for 2 weeks (they blunt healing), and a coordinated PT program over weeks 2–12 to translate the biology into durable function. You can drive home from either procedure.
- At your LAOSS visit we work through four things: (1) your diagnosis on exam and imaging — inflammation-driven pain leans cortisone, tissue degeneration leans PRP, tendons almost always lean PRP; (2) your timeline — fast functional relief vs longer-game durability; (3) cost and insurance — covered cortisone vs $500–$2,000 self-pay PRP; and (4) what comes next — a planned knee replacement in the next 3 months rules out cortisone, while a goal of delaying surgery 1–3 years often favors PRP. We don't sell packages and we won't push a procedure we don't believe fits your case.
Ready when you are
Get an honest answer on which one fits.
Book a visit at any of our eight Los Angeles-area offices. We'll examine the joint, image it on-site, and tell you straight whether cortisone, PRP, both, or neither is the right next step.
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