How one damaged cartilage spot differs from a worn joint

What to ask before microfracture surgery

During microfracture surgery, a surgeon opens tiny holes in the bone below one damaged cartilage spot. Those holes let marrow cells enter and grow a covering called repair tissue. That covering is rougher and less lasting than the smooth cartilage you were born with. This surgery is for selected spots, not wear across an older joint.

The whole knee matters too.

Ask how large the spot is and whether nearby cartilage is sound. Also ask about alignment, meaning whether your leg sits straight or the knee bows inward or outward. Age and strength matter too. Results in younger adults with one damaged spot can't be promised to everyone.

How to ask what the scans actually show

An MRI can show one missing patch of cartilage and harm in the softer parts around the joint. An X-ray can show whether the gap between bones has narrowed. It also shows whether the leg sits straight. Neither scan can tell the doctor exactly how much you hurt, and it can't choose treatment.

Don't let one scan choose for you.

Ask whether damage stays in a small area or reaches across the joint. Check that the scan finding agrees with the sore place. Then ask what the treatment is supposed to change. Less soreness and new cartilage on a scan aren't the same result. I'd want the answer stated plainly.

What to do while the cause is being checked

Avoid the twist or deep bend that makes the joint catch. Keep safer motion so you don't lose strength. If it swells after activity, do less next time and let it settle. Get prompt care when the knee locks, buckles, or won't hold your weight.

For now, protect your movement without forcing it.

After the exam, QC Kinetix medical providers—the people who assess the joint in Peoria—can discuss regenerative treatment, meaning non-surgical care made with body material, such as PRP, or platelet-rich plasma: for PRP, blood is spun so the clotting parts gather in less fluid, which is then placed into the joint to help soreness or movement, not fill the damaged cartilage spot.

Sources

1. 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.

2. 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.

3. 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.

4. A systematic review of the discordance between clinical and radiographic knee osteoarthritis: many people with severe-looking x-rays have little pain, and many with disabling pain have modest radiographic change. This is the reason a post-treatment scan is a poor proxy for how someone feels, in either direction.

   Bedson J, et al. — The discordance between clinical and radiographic knee osteoarthritis: a systematic search and summary of the literature.. BMC musculoskeletal disorders, 2008. DOI: 10.1186/1471-2474-9-116.

5. A 2026 systematic review and meta-analysis of 28 randomized trials of intra-articular mesenchymal stem cell-based therapies in knee OA found significant improvements in several pain and function measures (delta-VAS MD -1.67; KOOS pain MD 15.37) but NO significant difference in WOMAC, KOOS quality of life or the Lequesne index, and MRI-based WORMS scores were non-significant - indicating no consistent structural benefit. Its own conclusion: these therapies serve a primarily SYMPTOM-modifying rather than STRUCTURE-modifying role, with higher frequencies of local reactions to weigh against the symptomatic benefit.

   Awad G, et al. — Efficacy and safety of intra-articular mesenchymal stem cell-based therapies in knee osteoarthritis: A systematic review and meta-analysis of randomized controlled trials.. Clinical rheumatology, 2026. DOI: 10.1007/s10067-026-08042-w.