Knee Osteoarthritis and Platelet-rich plasma (PRP): what the trial registry contains

Why this is studied in Knee Osteoarthritis

The knee is the most-studied joint in cell therapy: accessible, high-volume, with validated pain and function scales and imaging that can track cartilage. Proposed mechanisms are anti-inflammatory and chondroprotective rather than cartilage regrowth, despite marketing that regularly implies new cartilage.

What PRP means in this table

Platelet-rich plasma is a blood product, not a stem-cell product, though it is routinely sold as part of the same package. Preparation varies enormously between systems — platelet concentration, leukocyte content and activation all differ — so the label describes a category of procedure rather than a defined substance, which is the main reason its trial literature is so inconsistent.

The numbers

Every figure below comes from one reproducible query (knee osteoarthritis x platelet-rich plasma) run against ClinicalTrials.gov API v2 on 2026-08-29.

How mature is this evidence?

Sponsors have committed to confirmatory designs here — 35 of 163 records at Phase 3 or 4 — which raises the standard of evidence a commercial claim should be held to.

Registrations do not all survive contact with recruitment — 80 completed here, 10 stopped early, giving a 6% attrition rate.

Median planned enrolment is 78 participants (largest single study: 10,000). Trials of this size can describe safety and generate hypotheses; detecting a modest clinical benefit reliably usually needs substantially larger numbers with a control group.

Where the studies are

Across 36 countries with registered sites, United States dominates at roughly 27% — a concentration driven by funding and regulation rather than by clinical outcome.

Legal pathway differs by country — see where cell therapy is legal, by country.

Who runs them

Lead sponsors split roughly 7 academic or hospital against 14 commercial — a commercial profile. Commercial sponsorship is not a red flag by itself, but it changes publication incentives.

• Istituto Ortopedico Rizzoli — 6 records
• Kaohsiung Veterans General Hospital. — 4 records
• Regen Lab SA — 3 records
• National Taiwan University Hospital — 3 records
• Mayo Clinic — 3 records
• Exactech — 2 records

Representative registered studies

Recruiting studies first, then the most advanced phases. Each identifier links to the registry record, where eligibility criteria, outcome measures and contacts are published.

What this page does and does not tell you

A registry is a plan repository. Counting entries tells you what people intended to study, which is a weaker thing than what they found.

If a clinic offers you this today, the useful question is not "is there research?" but "which of these registered studies is mine part of, and if none, what evidence applies to the exact product I am being sold?" The Provider Question Builder turns that into a scored checklist.

Frequently asked

How many PRP studies for Knee Osteoarthritis are recruiting right now?

25 of 163 registered records were listed as recruiting in the 2026-08-29 snapshot. Recruitment status changes frequently; the registry record is authoritative.

Is PRP an approved treatment for Knee Osteoarthritis?

Registration on ClinicalTrials.gov is not approval. Approval is granted by a regulator for a specific product and indication after review of submitted evidence. 163 registered studies tell you research exists, not that a product cleared review.

How advanced is the research on PRP for Knee Osteoarthritis?

35 of 163 records carry a Phase 3 or Phase 4 label and 80 are marked completed. Registrations run from 2008 to 2026.

Registry and literature counts retrieved 2026-08-29 (ClinicalTrials.gov API v2; PubMed E-utilities). Registration or publication volume measures research activity, not effectiveness or approval. Educational information — not medical advice; verify product, indication, legal pathway and evidence with an independent qualified physician. Page generated 2026-08-29. See our editorial standards.