Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Two-Year Follow-up of a Prospective Randomized Trial

D. Saris*, A. Price, W. Widuchowski, M. Bertrand-Marchand, J. Caron, J.O. Drogset, P. Emans, A. Podskubka, A. Tsuchida, S. Kili, D. Levine, M. Brittberg, the SUMMIT study group

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


Background: Randomized controlled trials studying the efficacy and safety of matrix-applied characterized autologous cultured chondrocytes (MACI) versus microfracture (MFX) for treating cartilage defects are limited.

Purpose: To compare the clinical efficacy and safety of MACI versus MFX in the treatment of patients with symptomatic cartilage defects of the knee.

Study Design: Randomized controlled clinical trial; Level of evidence, 1.

Methods: Patients enrolled in the SUMMIT (Demonstrate the Superiority of MACI implant to Microfracture Treatment) trial had >= 1 symptomatic focal cartilage defect (Outerbridge grade III or IV; >= 3 cm(2)) of the femoral condyles or trochlea, with a baseline Knee Injury and Osteoarthritis Outcome Score (KOOS) pain value

Results: Of the 144 patients treated, 137 (95%) completed the 2-year assessment. Patients had a mean age of 33.8 years and a mean lesion size of 4.8 cm(2). The mean KOOS pain and function subscores from baseline to 2 years were significantly more improved with MACI than with MFX (pain: MACI, 37.0 to 82.5 vs MFX, 35.5 to 70.9; function: MACI, 14.9 to 60.9 vs MFX, 12.6 to 48.7; P = .001). A significant improvement in scores was also observed on the KOOS subscales of activities of daily living (MACI, 43.5 to 87.2 vs MFX, 42.6 to 75.8; P <.001), knee-related quality of life (MACI, 18.8 to 56.2 vs MFX, 17.2 to 47.3; P = .029), and other symptoms (MACI, 48.3 to 83.7 vs MFX, 44.4 to 72.2; P <.001) for patients treated with MACI compared with MFX. Repair tissue quality was good as assessed by histology/MRI, but no difference was shown between treatments. A low number of treatment failures (nonresponders: MACI, 12.5% vs MFX, 31.9%; P = .016) and no unexpected safety findings were reported.

Conclusion: The treatment of symptomatic cartilage knee defects >= 3 cm(2) in size using MACI was clinically and statistically significantly better than with MFX, with similar structural repair tissue and safety, in this heterogeneous patient population. Moreover, MACI offers a more efficacious alternative than MFX with a similar safety profile for the treatment of symptomatic articular cartilage defects of the knee.

Original languageEnglish
Pages (from-to)1384-1394
Number of pages11
JournalThe American Journal of Sports Medicine
Issue number6
Publication statusPublished - Jun 2014


  • cartilage repair
  • clinical outcomes
  • knee
  • matrix-applied characterized autologous cultured chondrocytes (MACI) implant
  • microfracture
  • KNEE

Cite this