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Last checked 10 August 2026

Knee Joint DisordersWhat stem cell therapy may—and may not—change for your knee.

If you have knee OA, the best current review found a small pain and function benefit over placebo at about six months. It didn’t establish a cure, reliable cartilage regrowth, or any guarantee you can avoid surgery.[1]

25randomized trials in the 2025 Cochrane review
1,341participants across those trials
6 momain window for pain and function evidence
Check My Options Review My Information

We organize your records, help prep questions for providers, coordinate appointments and handle translation. But the diagnosis—and any treatment decision—belongs to your doctor.

Clinical consultation visual for reviewing knee joint treatment information

What the best data actually tell us

The average benefit is modest, and the certainty is low.

The 2025 Cochrane review pulled together 25 randomized trials covering 1,341 people. Eight were placebo-controlled, with 459 participants. One big problem: every study used a different cell source, prep method and dose.[1]

Pain at 6 months 1.2 / 10 Points better than placebo. Seven studies, 445 people; 95% CI 0 to 2.5 points better. Low-certainty evidence.
Function at 6 months 14.2 / 100 Points better than placebo on a scale where lower was better. Seven studies, 432 people; 95% CI 3.1 to 25.3. Low certainty.
Reported success 683 vs 530 Per 1,000 people at end of follow-up. Four trials, 348 people; RR 1.29, 95% CI 1.10 to 1.53. Very low certainty.
Serious AEs reported 16 vs 23 Per 1,000 people in stem-cell and placebo groups. Seven trials, 461 people; RR 0.72, 95% CI 0.20 to 2.64. Too few events for a firm safety conclusion.

The quality-of-life evidence was very uncertain, and not one trial tracked whether OA actually got worse on X-rays. These are group findings—they can’t predict what will happen to your knee.[1]

Compare the Details
Patient records and knee imaging prepared for an evidence review
Start with your diagnosis

Does the research resemble your case?

Most useful data are for diagnosed knee osteoarthritis.

Moderate OA is common in the evidenceCochrane found trials were predominantly small; average participant age across trials ranged from 51 to 66 years and symptom duration from 1 to 10 years.[1]
Kellgren-Lawrence grade 3 has phase III placebo dataA 2023 multicenter trial enrolled 261 people with symptomatic grade 3 knee OA and tested one specific culture-expanded adipose-derived cell product.[2]
Grades 2 to 4 have comparative injection dataA 480-person randomized trial included K-L grades II to IV. At one year, none of three cell-based options was superior to corticosteroid injection.[10]
Do not transfer OA results to a different knee problemMeniscal tears, ligament injury, inflammatory arthritis, infection, fracture, osteonecrosis and major deformity need diagnosis-specific evidence.
Knee OA research in JapanMSC research for chronic pain
What canchange?

What improvement actually looks like

Pain and function can improve. Structural repair is not established.

Pain

In the 261-person phase III trial, improvement on a 100-mm pain scale was 25.2 mm with the cell product versus 15.5 mm with placebo at six months, a 9.7-mm between-group difference.[2]

Function

In the same trial, total WOMAC improvement was 21.7 versus 14.3 points at six months. This result applies to that exact product and grade 3 OA population.[2]

Cartilage on MRI

The 261-person trial found no significant difference in cartilage-defect change at six months. The 480-person trial also found no significant MRI osteoarthritis-score change at one year.[2][10]

Avoiding surgery

No reliable percentage can be given for avoiding a future knee replacement. The trials above were designed mainly around pain, function and shorter-term imaging outcomes.

For knee OA, a “survival rate” doesn’t answer the useful question. Track pain, walking, stairs, daily activity, adverse events, imaging when indicated, and whether another procedure becomes necessary.
See What Fits My Situation

Do not compare only the word “stem cell”

First identify the exact cell product.

Two quotes can describe very different products. Before you compare prices or expected results, get the same six details in writing.

01
Cell sourceYour own fat or bone marrow, donor cells, or another source.
02
ProcessingPoint-of-care preparation, culture expansion or another processing method.
03
Dose and scheduleDelivered cell count, one injection or repeated injections, and timing.
04
Quality checksSterility, viability, identity, release criteria and where processing takes place.
05
Evidence matchWhich published study used a similar product in patients with a similar grade of OA.
06
Fallback planWhat happens if pain or function does not improve.
How cell processing centers workRegenerative medicine overview
Clinical information visual for comparing stem cell source, processing and dose
Compare like with like

Safety and regulation

Short-term safety data are reassuring, but incomplete.

12.3%Transient adverse-event rate in a systematic review of 48 studies and 1,924 patients. Swelling and injection-site pain were most common.[3]
What that review actually found

No infection, fat embolism or other medical complication was reported in the included studies; local pain and swelling generally lasted less than four weeks. The authors still called for longer-term safety data because protocols varied.[3]

Newer randomized evidence

A 2026 meta-analysis of 28 randomized trials found more injection-site pain (RR 2.04) and joint swelling (RR 3.39) with MSC-based therapies, while serious complications remained uncommon and were not significantly increased.[12]

United States

FDA states that regenerative medicine therapies are not approved for orthopedic conditions such as osteoarthritis or knee pain. It also warns that unapproved products can carry contamination, infection, immune-reaction and other risks.[4]

Japan

Japan uses separate legal pathways for the provision of regenerative medicine and for approval of regenerative medical products. MHLW states that required procedures must be completed before regenerative medicine is provided or specified processed cells are manufactured.[5][6]

Check the exact regulatory route

A submitted provision plan under Japan’s safety framework is not the same thing as PMD Act marketing approval for a regenerative medical product. Ask which status applies to the exact product being discussed.[5][6]

Ask What to Verify
Cost comparison and records prepared for a knee cell therapy review
Ask for the full amount

What prices actually look like

Prices can vary sharply even within one market.

Alternative practicesUS$4,594Mean advertised price for one stem-cell knee injection.
Orthopaedic sports-medicine practicesUS$1,452Mean advertised price for one stem-cell knee injection.

These figures come from a 2025 Chicago-area market study and are not a Japan price or personal quote. The study found significantly higher and more variable prices in the first group.[7]

AssessmentReview of diagnosis, imaging and baseline tests.
Cell collectionOnly when your own tissue is collected.
ProcessingPreparation, culture or release testing where applicable.
AdministrationInjection, guidance and related medicines.
Follow-upReview dates, outcome checks and repeat imaging if planned.
Travel supportTranslation, scheduling and local coordination if needed.
Before paying, ask for one written total that states the exact product, number of injections, what follow-up is included, what is self-paid, and what extra charges can occur.
Get a Clearer Quote

What recovery actually looks like

Use fixed checkpoints so you can tell whether anything changed.

Before
Record a baselineKeep your OA grade, imaging report, current pain score, walking or stair limits, medicines and previous injections or surgery. Without a baseline, later improvement is hard to judge.
First 4 weeks
Local soreness or swelling is the common short-term issueThe 48-study safety review reported transient adverse events in 12.3% of 1,924 patients, most often swelling and injection-site pain, generally lasting less than four weeks.[3]
3–6 months
This is where many trials judge symptom changeCochrane used three to six months as the main time point for pain and function. The 261-person phase III trial also reported its main symptom differences at six months.[1][2]
12 months
A large comparative trial found no cell option superior to steroidIn the 480-person MILES trial, none of three cell-based injections was superior to corticosteroid at one year, and no group had a significant MRI osteoarthritis-score change from baseline.[10]
Up to 60 months
Long follow-up exists, but the sample is smallA 2026 phase I/II study had 29 completers. Blinding was maintained for 12 months; after that, 21 treated participants continued follow-up to 60 months. Improvements declined after 36 months and approached baseline by month 60. Larger trials are still needed.[8]

Ask how pain and function will be measured, when each review happens, what activity plan is expected, and what the next step is if there is no meaningful improvement.

Get a Clearer Plan

Where your case sits

Your OA grade and current function change the decision.

K-L 2–3 OAThis range is well represented across published trials. Compare your proposed product with a study that used a similar cell source, preparation, dose and follow-up.
K-L 4 OAThe 480-person trial included grade IV disease but found no cell-based option superior to corticosteroid at one year. A grade alone does not predict a personal response.[10]
Already advised replacementFor moderate-to-severe symptomatic OA after failed nonoperative care, ACR and AAHKS conditionally recommend proceeding with indicated joint replacement rather than delaying it for more nonoperative treatment of the joint problem.[11]
Different diagnosisMeniscal or ligament injury, inflammatory arthritis, infection, fracture and osteonecrosis are not answered by knee-OA injection trials. Use evidence for the actual diagnosis.

AAOS patient guidance also notes that evidence is not strong enough to show injected stem cells reliably build healthy new tissue, and advanced arthritis is commonly managed with joint replacement.[9]

Knee osteoarthritis records and imaging used to compare care options
Match evidence to your grade

The trials behind the numbers

Large studies do not all give the same answer.

2023
261-person phase III placebo trial

For one autologous culture-expanded adipose-derived MSC product in K-L grade 3 OA, pain and WOMAC improved more than placebo at six months. MRI cartilage-defect change was not significantly different.[2]

Positive symptom signal
No MRI difference
2023
480-person randomized comparative trial

Bone-marrow aspirate concentrate, stromal vascular fraction and umbilical-cord-tissue MSCs were compared with corticosteroid. At one year, none was superior for the primary pain outcomes; MRI scores did not significantly change.[10]

K-L II–IV
440 primary analyses
2025
Cochrane living systematic review

Twenty-five randomized trials and 1,341 participants. Compared with placebo, stem-cell injections may slightly improve pain and function up to six months, but certainty was low.[1]

Broadest review here
Low certainty
2026
Meta-analysis of 28 randomized trials

Modest pain benefit and improvement in selected KOOS domains were reported, but MRI-based WORMS did not show consistent structural benefit. Local injection pain and swelling were more frequent.[12]

Evidence through Dec 2025
No consistent MRI benefit
2026
Small study with 60-month follow-up

Twenty-nine participants completed a phase I/II study. Placebo blinding lasted 12 months; the treated arm then continued follow-up. Clinical improvement declined after 36 months and approached baseline at 60 months.[8]

21 treated long term
Small sample
Read the knee OA research guide
Patient support visual for organizing records, questions, translation and follow-up information
One clearer case file

Where we fit in

Turn scattered records and claims into a clearer decision file.

Record packOrganize diagnosis, imaging reports, current medicines, prior care and your main questions.
Evidence checkMatch the proposed cell source, dose and protocol with published evidence instead of relying on a headline claim.
Verification questionsPrepare questions about regulation, processing, sterility, follow-up and the fallback plan.
Coordination and translationSupport appointment scheduling, document translation and communication where needed.
Cost and follow-up recordKeep the itemized quote, review dates, rehabilitation instructions and next-step plan in one place.
Explore regenerative medicine topicsUnderstand cell processing
Start With My RecordsTalk It Through

We don’t diagnose, prescribe, guarantee eligibility, promise a cure or tell you whether to go ahead. That kind of decision needs a licensed doctor who’s examined you.

Things to nail down before you pay

Use the study details, not a headline claim.

If someone gives you an exact success percentage, ask which cell product, OA grade, outcome measure and follow-up period produced that number.

Can stem cells cure knee osteoarthritis?
No predictable cure has been established. Current randomized evidence supports, at most, modest symptom improvement for some protocols. Consistent cartilage regeneration or reversal of OA has not been established.
What is the success rate?
There is no universal rate. In the Cochrane review, 683 per 1,000 people in stem-cell groups reported treatment success versus 530 per 1,000 with placebo, but certainty for this outcome was very low.
Does MRI show cartilage regrowth?
Not consistently. A 261-person phase III trial found no significant cartilage-defect difference at six months, and a 480-person trial found no significant MRI OA-score change at one year. A much smaller 29-person study reported MRI improvement at 12 months, so structural results remain uncertain.
Could this help me avoid knee replacement?
No reliable avoidance rate has been established. If you already have moderate-to-severe symptomatic OA, have failed nonoperative care and have been advised joint replacement, current ACR/AAHKS guidance does not support delaying indicated surgery simply to try more nonoperative options.
How soon would I know whether it helped?
Three to six months is a common trial checkpoint for pain and function. Longer-term benefit varies. In one small 2026 study, improvement declined after 36 months and approached baseline by 60 months.
What should I ask about the cells?
Ask the tissue source, whether cells are your own or donor-derived, processing method, delivered dose, release tests, sterility controls, number of injections, regulatory route and follow-up plan. Then ask which published study used a similar product.
What records are useful for a first review?
Send your diagnosis summary, recent X-ray or MRI report, OA grade if known, current medicines, previous injections or surgery, major health conditions, current pain and walking limits, and any proposal or quote you are comparing.
Clinical evidence references reviewed for knee joint disorders and stem cell therapy

The evidence and regulation we relied on

Evidence used for the statements above

Evidence and rules change. This information is educational—it can’t stand in for a diagnosis, a prescription or a personal risk assessment from your own doctor.

Start with what you already have

Send your records, your current quote, or the questions you cannot get a clear answer to.

We’ll help you organize the information, spot what’s missing, prepare verification questions and get the cost and follow-up details into one clear file—before you decide what to do next.

Send What I Have Ask My Questions
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