Cartilage repair Glendale: what did the studies find?

Did people hurt less or move better?

A large study of platelet-rich plasma found no advantage over salt water for soreness. It also found no added cartilage on the scan.

That doesn't answer every question about every sore knee. It does mean relief and new cartilage are separate claims that need separate proof.

Ask whether people walked, stood or climbed stairs with less trouble. Those daily results say more than a research number with no plain meaning.

Did the operation help the same kind of knee?

Some MACI studies involved adults with one deep damaged spot. Their two-operation cell repair isn't the same care used for broad arthritis.

The long studies also disagreed when MACI was compared with microfracture. A good result for one damaged spot can't answer for wear across the knee.

How long did the change last?

Some research checked people soon after care, while other work followed them for years. An early drop in soreness doesn't show that relief will last.

Ask when the last check happened and whether more care followed. A study ending early can't promise how the knee will feel much later.

What if your knee still doesn't settle?

Natural pain treatments are available from QC Kinetix without surgery. Concentrated platelet-rich plasma uses your blood after its parts are separated.

The clinic keeps more platelets, tiny blood pieces that help clotting. Ask what proof supports less soreness or easier movement, when they'll check, and the follow-up cost.

Sources

1. At 14 to 15 years, the Norwegian multicentre randomised trial of 80 patients with a single symptomatic femoral condyle cartilage defect found no significant difference between autologous chondrocyte implantation and microfracture on any clinical scoring system. There were 17 failures in the ACI group versus 13 after microfracture, and more total knee replacements had been needed after ACI (6 versus 3).

   Knutsen G, et al. — A Randomized Multicenter Trial Comparing Autologous Chondrocyte Implantation with Microfracture: Long-Term Follow-up at 14 to 15 Years.. J Bone Joint Surg Am, 2016. DOI: 10.2106/JBJS.15.01208.

2. FDA biologics licence BL 125603 (Vericel) describes MACI verbatim as "an autologous cellularized scaffold product indicated for the repair of symptomatic, single or multiple full-thickness cartilage defects of the knee with or without bone involvement in adults." The licensed indication is a two-stage surgical implantation for full-thickness DEFECTS of the knee in adults. It is not an injection, it is not licensed for osteoarthritis, and it is not licensed for any joint other than the knee.

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

3. At two years in the randomised trial of ACI versus microfracture in 80 patients, both groups improved significantly, and the microfracture group's SF-36 physical component score improved significantly MORE than the ACI group's. Biopsies were obtained from 84% of patients and blinded histological evaluation showed no significant difference between the two repair tissues, with no association between histological quality and clinical outcome.

   Knutsen G, et al. — Autologous chondrocyte implantation compared with microfracture in the knee. A randomized trial.. J Bone Joint Surg Am, 2004. DOI: 10.2106/00004623-200403000-00001.

4. At five years the same randomised trial reported nine failures (23%) in each arm and satisfactory results in 77% of patients, with no significant clinical or radiographic difference between ACI and microfracture and again no correlation between histology and outcome. One-third of all patients already had radiographic signs of early osteoarthritis five years after surgery.

   Knutsen G, et al. — A randomized trial comparing autologous chondrocyte implantation with microfracture. Findings at five years.. J Bone Joint Surg Am, 2007. DOI: 10.2106/JBJS.G.00003.

5. In the SUMMIT randomised trial, 144 patients with at least one symptomatic Outerbridge grade III-IV knee defect of 3 cm2 or more (mean lesion 4.8 cm2, mean age 33.8) were randomised to MACI or microfracture. At two years, improvements in KOOS pain (37.0 to 82.5 versus 35.5 to 70.9) and function (14.9 to 60.9 versus 12.6 to 48.7) were significantly greater with MACI.

   Saris D, et al. — Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Two-Year Follow-up of a Prospective Randomized Trial.. Am J Sports Med, 2014. DOI: 10.1177/0363546514528093.

6. At five years, 128 of the 144 SUMMIT patients remained in follow-up and MACI's advantage over microfracture on the co-primary KOOS pain and function endpoint was maintained and remained statistically significant (P = .022), with activities of daily living also significantly better (P = .007).

   Brittberg M, et al. — Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Five-Year Follow-up of a Prospective Randomized Trial.. Am J Sports Med, 2018. DOI: 10.1177/0363546518756976.

7. The ACTIVE randomised trial assigned 390 patients aged 18-55 whose previous cartilage surgery had failed to autologous chondrocyte implantation or alternative surgical management. At five years there was NO evidence of a difference in Lysholm score (2.9 points, 95% CI -1.8 to 7.5; P = .46), about 55% were still experiencing benefit in the ACI arm, time to cessation of benefit was similar, and significantly more participants had a serious adverse event with ACI (P = .02). Previous marrow stimulation had a detrimental effect on ACI outcome.

   Snow M, et al. — A Randomized Trial of Autologous Chondrocyte Implantation Versus Alternative Forms of Surgical Cartilage Management in Patients With a Failed Primary Treatment for Chondral or Osteochondral Defects in the Knee.. Am J Sports Med, 2023. DOI: 10.1177/03635465221141907.

8. At ten years the same 390-patient ACTIVE trial found the ACI arm scored significantly higher on Lysholm (mean difference 7.3 points, 95% CI 2.5 to 12.1), while ten-year treatment failure rates were comparable at 29% versus 25% (HR 1.04). A sensitivity analysis accounting for later operations reduced the advantage to 3.8 points (95% CI -1.8 to 9.5). The five-year and ten-year readouts of the same trial point in different directions, which is why a single follow-up point should never be quoted alone.

   Snow M, et al. — Ten year follow-up of a randomized trial of autologous chondrocyte implantation versus alternative forms of surgical cartilage management in the knee.. Osteoarthritis Cartilage, 2026. DOI: 10.1016/j.joca.2026.03.112.

9. The NIHR health technology assessment of autologous chondrocyte implantation reviewed the trials and built a new economic model. Survival analysis suggested better long-term results with ACI than microfracture, and in most analyses the incremental cost-effectiveness ratios for ACI versus microfracture fell within a range usually considered acceptable. The assessment flagged the absence of randomised data beyond five years, and that the long-term data come from forms of ACI now superseded.

   Mistry H, et al. — Autologous chondrocyte implantation in the knee: systematic review and economic evaluation.. Health Technol Assess, 2017. DOI: 10.3310/hta21060.

10. FDA's consumer alert states verbatim of stem cell products, exosome products, adipose-derived stromal vascular fraction, umbilical cord blood, Wharton's Jelly and amniotic fluid products: "None of these products have been approved for the treatment of any orthopedic condition, such as osteoarthritis, tendonitis, disc disease, tennis elbow, back pain, hip pain, knee pain, neck pain, or shoulder pain." The only stem cell products carrying FDA licensure are blood-forming cells derived from umbilical cord blood, licensed only for disorders of blood production, and there are currently no licensed exosome products.

    U.S. Food and Drug Administration — Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes. FDA, Consumers (Biologics), 2020.