What to ask when someone says knee regeneration

What to ask about cartilage regeneration

When you hear a claim, ask whether it covers an X-ray or MRI, or less soreness and easier walking. A scan result and how the knee feels are different measures. One can change while the other stays the same.

Cartilage may look different on a scan without making sleep or walking easier. Exercise may ease soreness even when the scan doesn’t change. A small damaged spot isn’t the same as wear across much of the joint. Some operations repair a small spot, but office care doesn’t rebuild a worn knee.

Here’s the honest limit: regeneration can’t tell you what result to expect.

What to track at home

Track the same tasks each week. Note walking time, stairs, sleep, and soreness afterward. Check again after the care has had time to work. Memory isn’t always fair from day to day.

Don’t order another scan just to judge comfort. If soreness lasts, take your notes to a doctor. An exam can sort years of wear from a fresh injury. Ask what result is realistic and when to check it.

At its Chandler clinic, QC Kinetix has medical providers examine the knee before discussing non-surgical regenerative treatments, including platelet-rich plasma (PRP) or concentrated PRP: the clinic spins some of your blood to separate a platelet-rich liquid, which is then put into the joint.

Sources

1. FDA states plainly that no stem cell, exosome, stromal vascular fraction, umbilical cord blood, Wharton's jelly or amniotic-fluid product has been approved for the treatment of ANY orthopedic condition - it names osteoarthritis, tendonitis, disc disease, tennis elbow, back pain, hip pain, knee pain, neck pain and shoulder pain individually. The only FDA-approved stem cell products in the United States are cord-blood-derived blood-forming stem cells for disorders of the hematopoietic system, and there are currently no FDA-approved exosome products.

   US Food and Drug Administration, Center for Biologics Evaluation and Research — Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. FDA, 2020.

2. The RESTORE trial - a participant-, injector- and assessor-blinded RCT of 288 adults aged 50+ with symptomatic medial knee OA (Kellgren-Lawrence 2-3) - compared three weekly intra-articular PRP injections against saline placebo, with co-primary endpoints of 12-month knee pain and medial tibial cartilage volume on MRI. PRP did not beat placebo on either. It is the single best-designed test of the specific claim that PRP changes joint structure, and it was negative.

   Bennell KL, et al. — Effect of Intra-articular Platelet-Rich Plasma vs Placebo Injection on Pain and Medial Tibial Cartilage Volume in Patients With Knee Osteoarthritis: The RESTORE Randomized Clinical Trial.. JAMA, 2021. DOI: 10.1001/jama.2021.19415.

3. A four-arm, multicentre, single-blind phase 2/3 randomized trial of 480 knee OA patients (KL II-IV) compared autologous bone marrow aspirate concentrate, autologous adipose stromal vascular fraction and allogeneic umbilical-cord-tissue mesenchymal stromal cells against a corticosteroid injection control. At 12 months NONE of the three orthobiologic injections was superior to another, or to the corticosteroid control, and none of the four groups showed a significant change in MRI osteoarthritis score from baseline. No procedure-related serious adverse events occurred.

   Mautner K, et al. — Cell-based versus corticosteroid injections for knee pain in osteoarthritis: a randomized phase 3 trial.. Nature medicine, 2023. DOI: 10.1038/s41591-023-02632-w.

4. MACI (autologous cultured chondrocytes on a porcine collagen membrane, Vericel; STN BL 125603) IS an FDA-LICENSED cell therapy - and its approved indication is narrow and specific: repair of symptomatic, single or multiple FULL-THICKNESS cartilage defects OF THE KNEE, with or without bone involvement, in adults. It is not approved for osteoarthritis. The existence of one licensed cartilage cell therapy for focal defects is the sharpest available way to show what a licensed 'regeneration' product actually looks like, and how far it is from an injection for a worn joint.

   US Food and Drug Administration, Center for Biologics Evaluation and Research — MACI (autologous cultured chondrocytes on porcine collagen membrane). FDA, 2024.

5. The SUMMIT randomized trial treated 144 patients (mean age 33.8, mean lesion 4.8 cm2) with at least one symptomatic focal cartilage defect (Outerbridge III/IV, >=3 cm2) of the femoral condyle or trochlea. Matrix-applied characterized autologous cultured chondrocytes (MACI) improved KOOS pain (37.0 to 82.5) and function significantly more than microfracture (pain 35.5 to 70.9) at 2 years, with histological and MRI assessment of the repair tissue. This is what a positive cartilage-repair trial looks like - in young patients with a discrete hole, not a worn joint.

   Saris D, et al. — Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Two-Year Follow-up of a Prospective Randomized Trial.. The American journal of sports medicine, 2014. DOI: 10.1177/0363546514528093.

6. FORWARD, the longest disease-modifying osteoarthritis drug trial reported to date, gave intra-articular sprifermin (a recombinant FGF-18) or placebo to knee OA patients and followed 378 of them for 5 years. Sprifermin produced a significant, sustained dose-response INCREASE in total femorotibial cartilage thickness versus placebo - and WOMAC pain improved about 50% from baseline in ALL groups, including placebo. It is the cleanest demonstration in the literature that adding measurable cartilage and relieving pain are two different results, and that one does not deliver the other.

   Eckstein F, et al. — Long-term structural and symptomatic effects of intra-articular sprifermin in patients with knee osteoarthritis: 5-year results from the FORWARD study.. Annals of the rheumatic diseases, 2021. DOI: 10.1136/annrheumdis-2020-219181.