Published: 16 October 2026｜Last updated: 16 October 2026｜Sources verified: 16 October 2026
“Insurance” in this article refers to Japan’s public health insurance system
Some treatments are covered, but it depends which one. As of 1 January 2026, the autologous cultured cartilage product JACC is covered by Japanese public health insurance for knee osteoarthritis in patients who meet the criteria. That does not mean every knee regenerative treatment is reimbursed. Intra-articular stem cell injections and PRP are still generally offered as private-pay care.
Source: J-TEC news release on insurance coverage for cultured cartilage JACC (January 2026)
Headlines about knee regenerative medicine being covered by insurance tend to raise the same three questions. Will a single injection grow my cartilage back? A treatment that used to cost several million yen — do I now pay only a fraction of that? My knee has hurt for years, am I still eligible?
The phrase “regenerative medicine” cannot answer any of these. Start with the formal name of the treatment. Only then can you work out what it actually does, whether it suits your situation, and which part of the cost insurance covers.
What is knee osteoarthritis, and why do Japanese sources use a different name?
Knee osteoarthritis is a condition in which the joint cartilage wears down and the surrounding tissues change as well. Japanese medical websites write it as 変形性膝関節症 (henkeisei shitsu kansetsu shō). It is the same condition. Common symptoms include pain when standing up or starting to walk, difficulty on stairs, fluid build-up in the joint, and reduced range of motion. If you are searching Japanese hospital websites, 変形性膝関節症 is the term to use.
Source: Japanese Orthopaedic Association, knee osteoarthritis
Articular cartilage and the meniscus are two different structures inside the knee. The meniscus distributes load, and damage to it can accelerate joint degeneration. Even so, not all knee pain comes down to “bone grinding on bone.” Before choosing a treatment, a proper diagnosis should clarify how your pain, cartilage damage, meniscus and overall leg alignment relate to one another.
What is the difference between cultured cartilage, stem cells and PRP?
The easiest difference to remember is the material. Cultured cartilage transplantation uses your own cartilage cells. Stem cell treatment uses cells from a specific tissue source. PRP uses a component of your own blood. These are not premium, mid-range and budget versions of the same treatment.
| Item | Cultured cartilage transplant (JACC) | Intra-articular stem cell injection | PRP injection |
|---|---|---|---|
| Material used | Tissue grown from your own cartilage cells | Your own fat, synovium or other tissue; the source varies by protocol | Platelet-rich plasma prepared from your own blood |
| Process | Cartilage is harvested, cultured outside the body, then implanted surgically | Tissue is harvested, cells are processed or cultured, then injected into the joint (varies by protocol) | Blood is drawn, prepared, then injected into the treatment site |
| Main aim | Repair of eligible cartilage defects and symptom improvement | Effects on pain, function and the joint environment are still under study | Uses platelet-derived components to try to improve pain and function |
| Japanese public insurance | Covered when the indication and facility requirements are met | Usually private-pay | Usually private-pay for outpatient knee osteoarthritis treatment |
| Key point | Involves surgery and a rehabilitation plan | Different cell types and preparation methods cannot be treated as equivalent | PRP is neither a stem cell therapy nor a cartilage graft |
Sources: J-TEC patient information / Dokkyo Medical University Saitama Medical Center. This table is for telling the categories apart. For the actual steps and goals, follow your treating physician’s explanation.
Which knee regenerative treatments does Japanese insurance actually cover?
What changed is specific: coverage for the cultured cartilage product JACC was extended to knee osteoarthritis. Stem cell injections were not brought under insurance across the board. The indication includes two conditions: clinical symptoms that have not improved with conservative treatment such as exercise therapy, and a cartilage defect of at least 2 square centimetres in the area being treated.
Source: J-TEC, JACC indication and insurance conditions for knee osteoarthritis
A diagnosis of knee osteoarthritis is therefore only the starting point. Your doctor still has to assess where the damage is, the overall state of the joint, and whether this treatment addresses the problem you actually have. The hospital and the surgeon must also meet defined requirements.
The condition added was knee osteoarthritis. You cannot extend that to “all joint conditions,” and it does not mean cell therapy for meniscus injury gained the same insurance status. Cell-based meniscus repair follows a separate research and development track.
Source: Institute of Science Tokyo, meniscus regenerative medicine research
Does cultured cartilage transplantation require surgery, or can it be done in a day?
It requires surgery and cannot be planned like a single outpatient injection. The process involves harvesting your own cartilage tissue, culturing it outside the body, and then implanting it, followed by rehabilitation. Published hospital information notes that weight-bearing on the treated leg may need to be restricted in stages after surgery, and that crutches may be required.
Source: Nadogaya Hospital, autologous chondrocyte implantation
Beyond cost, these are worth asking about in advance:
- ✓How many hospital admissions are needed, and how long is each stay
- ✓When you can expect to walk normally, drive, and return to work
- ✓Whether a procedure such as an osteotomy is needed at the same time
- ✓Whether stairs at home will be manageable during recovery
Note: all of this varies with the surgical plan. Another patient’s recovery timeline cannot simply be applied to yours.
How much does it cost, and what do you pay with insurance?
Total medical cost, product price and the patient’s out-of-pocket amount are three different figures. When you see “several million yen for treatment,” check what that figure includes before moving on to the insurance question.
Source: J-TEC pricing information
Figures like “JPY 4.5 million in total” only become comparable once you know which hospital they came from and what stage of care they cover. One clinic’s total is not the national going rate for knee regenerative medicine in Japan.
Private-pay prices also vary with what the treatment involves. Dokkyo Medical University Saitama Medical Center, for example, publishes PRP at JPY 99,660 and autologous synovial stem cell therapy at JPY 2,488,000, both tax-inclusive and explicitly outside insurance coverage. That is one institution’s example, not a national benchmark.
Source: Dokkyo Medical University Saitama Medical Center, published fees
When comparing quotes, ask for it in writing: one knee or both, how many sessions, and whether examinations, tissue harvesting, culturing, injection, follow-up visits and rehabilitation are included.
Can the High-Cost Medical Expense Benefit make private-pay treatment cheaper?
No. Japan’s High-Cost Medical Expense Benefit (kōgaku ryōyōhi) reduces out-of-pocket costs within insured care only. An expensive private-pay treatment does not become an insured one because of its price. Costs outside insurance, such as part of your meals or a private room supplement, are not simply added into the calculation either.
Source: Ministry of Health, Labour and Welfare, guide to the High-Cost Medical Expense Benefit
For treatments that are covered, your share also depends on age, income, the period in which it applies, and whether the course of treatment crosses a calendar month. The system has been revised, so use the rules in effect at the time of your visit and confirm with your insurer or the hospital’s billing desk. The “you’ll only pay a few tens of thousands of yen in the end” figures circulating online should not be treated as your own estimate.
Source: Ministry of Health, Labour and Welfare, High-Cost Medical Expense Benefit
If you travel to Japan for treatment, do you get the same insured price?
You cannot assume so simply because a treatment is now covered in Japan. Japanese public health insurance applies to people who are enrolled in it. Whether you qualify depends on your residency and enrolment status in Japan, not on the treatment itself.
If you are not enrolled, the figures above — the JPY 2,890,000 listing, the percentage co-payment — do not describe what you will pay. Ask the hospital directly for a private-pay quotation and request a written breakdown of what it includes.
Whether your own health insurance or a private medical policy will reimburse you is a separate question for your insurer, and Japanese co-payment rates cannot be applied to it. It is also worth settling the practical side at the booking stage: scheduling, interpretation, post-treatment follow-up, and how rehabilitation continues once you are home.
Can stem cell treatment really regrow cartilage?
Not something that can be guaranteed at present. Pain improving and cartilage regeneration being demonstrated are two different findings.
A phase III multicentre randomised trial conducted in South Korea in 2023 enrolled 261 patients with Kellgren-Lawrence grade 3 knee osteoarthritis and compared an intra-articular injection of autologous culture-expanded adipose-derived mesenchymal stem cells against placebo. At six months, the cell therapy group showed better improvement in pain and function, but there was no significant between-group difference in cartilage defect changes on MRI.
Source: Kim KI, et al. Am J Sports Med. 2023;51(9):2243-2253
A separate multicentre randomised trial analysing 440 patients compared several cell preparations — bone marrow-derived, adipose-derived and umbilical cord-derived — against corticosteroid injection, and found no significant advantage for cell therapy at one year. Because the protocols differ between studies, one positive result cannot establish that all stem cell treatments work, and one negative result cannot settle the question for every approach.
Sources: Mautner K, et al. Nat Med. 2023;29(12):3120-3126 / follow-up report from the same research group (Am J Sports Med, 2025)
When someone explains how effective a treatment is, ask one follow-up question: does “it worked” mean the pain score went down, that walking became easier, or that imaging confirmed a structural change in the cartilage? The answer tells you what the treatment can realistically offer you.
PRP is cheaper — is it reasonable to start there?
Price is not a substitute for assessing the indication. PRP and cultured cartilage transplantation differ in both material and method, so PRP is not a cheaper version of the latter.
PRP is also not risk-free simply because it uses your own blood. Treatment information published by Nippon Medical School notes that pain may intensify for a short period after injection and that follow-up observation is needed. Blood-derived preparations come in several types, and the umbrella term “PRP-related treatment” does not mean the composition, the evidence and the treatment schedule are the same.
Source: Nippon Medical School Hospital, Department of Orthopaedic Surgery
If your current treatment is not delivering, these are the questions worth discussing: which symptom affects your daily life most right now, whether the current treatment has been carried out fully, what you want the next option to improve, and how the plan changes if it does not work. Price alone is a poor basis for the decision.
What should you ask at a first consultation about regenerative medicine?
Standard options for knee osteoarthritis include exercise therapy and rehabilitation, weight management, medication, certain intra-articular injections, and surgery. Your doctor selects an approach based on your symptoms and examination findings. The arrival of regenerative medicine does not make these treatments less important.
Source: Japanese Orthopaedic Association
Take these six questions with you:
For treatments provided under a registered regenerative medicine provision plan, you can also cross-check the published treatment name against the informed consent documents. Plan submission, product approval, insurance coverage and evidence of efficacy are four separate pieces of information. Confirm them one at a time.
Source: Ministry of Health, Labour and Welfare, regenerative medicine provision plans
Frequently asked questions
What we offer at our clinic
Ginza YR Clinic is an appointment-only private-pay clinic. What we provide is regenerative medicine outside Japanese public health insurance: stem cell therapy, PRP and intravenous therapies.
The cultured cartilage transplantation (JACC) discussed in this article is insured surgical care, performed at certified institutions by qualified surgeons. We do not perform this procedure. If you are considering JACC transplantation under insurance, please consult an accredited implanting facility.
News that knee regenerative medicine is now insured does not mean that our private-pay fees are reduced by insurance. Which option fits your situation is something we explain after examining you.
Consultations and appointments
We see patients by appointment only. We review your current symptoms and treatment history first, and only propose a treatment once we have confirmed that it is appropriate for you.
When choosing a treatment for your knee, get three things clear first: what the treatment actually does, why it suits you, and which part of the cost insurance covers. Once those are settled, you are in a position to compare benefits, costs and recovery.
Note: This article provides general medical information and is not a substitute for individual diagnosis. For indications, pricing and insurance rules, follow the official explanation given at your consultation. Regenerative treatments provided at our clinic are private-pay and are carried out under Japan’s Act on the Safety of Regenerative Medicine. Results vary between individuals.
References and sources
- Japan Tissue Engineering Co., Ltd. (J-TEC), news release and product information for autologous cultured cartilage JACC
- Japanese Orthopaedic Association, knee osteoarthritis
- Institute of Science Tokyo, knee joint conditions / meniscus regenerative medicine research
- Dokkyo Medical University Saitama Medical Center, Department of Orthopaedic Surgery, treatment and fees for knee osteoarthritis
- Nadogaya Hospital, autologous chondrocyte implantation
- Nippon Medical School Hospital, Department of Orthopaedic Surgery, treatment information
- Ministry of Health, Labour and Welfare: High-Cost Medical Expense Benefit / advanced medical care / regenerative medicine provision plans
- Kim KI, et al. Clinical Efficacy and Safety of the Intra-articular Injection of Autologous Adipose-Derived Mesenchymal Stem Cells for Knee Osteoarthritis: A Phase III, Randomized, Double-Blind, Placebo-Controlled Trial. Am J Sports Med. 2023;51(9):2243-2253.
- Mautner K, et al. Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial. Nat Med. 2023;29(12):3120-3126.