MACI Science & Clinical Data
Important Safety Information
Full Prescribing Information
Cartilage Repair Blog
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Intended for U.S. health care professionals only

Knee cartilage injuries will often get worse with time, if left untreated

A study of patients undergoing cell-based knee cartilage repair found that lesions can progress and new lesions can form as time between cartilage biopsy and implantation increases.1 For patients with ≤4 cm2 accessible defects of the knee, early diagnosis and treatment may minimize lesion progression and the need for open ACI.1 If conservative treatment has not worked to relieve pain associated with knee cartilage damage, MACI may be an appropriate treatment option.

Cartilage defect expansion1

0.6 cm² mean change in defect size between biopsy & implantation

0.11 cm² increase in defect expansion per month delay to implantation

New high-grade cartilage defects1

16.2% of patients developed a new high-grade cartilage defect

155 days mean time between cartilage biopsy & implantation

Cartilage Damage
MACI Implanted

MACI is autologous chondrocyte implantation, simplified2

MACI is less invasive—may be done through a mini-arthrotomy or arthroscopy.

MACI is reproducible—regardless of implantation technique or defect size, MACI delivers a controlled, uniform dose of characterized cells to the defect area.

MACI is simplified—does not require supplemental suture fixation.

See how MACI works

The science behind MACI

MACI cartilage repair vs. microfracture: improvements in pain and function3

A statistically significantly greater percentage of patients treated with MACI experienced clinically meaningful improvements in both pain and function at 2 years when compared to microfracture.3

In a follow-up extension study, improvements in pain and function at Year 2 were maintained with MACI at Year 5.4

Mean patient-reported KOOS scores at Year 2 and Year 54

KOOS Scores

Baseline KOOS Scores for MACI implant patients:
37.1 Pain/15.4 Function

Baseline KOOS Scores for Microfracture patients:
35.2 Pain/11.9 Function

Legend for chart of >Mean patient-reported KOOS scores at year 2 and year 5

Patient-reported KOOS responder rates at Week 104

The responder rate was higher with MACI implant when compared with microfracture (P=0.016). Response is defined as ≥10-point improvement in both pain and function.3

MACI KOOS Responder Rate

MACI

Microfracture KOOS Responder Rate

Microfracture

MACI is a 3rd generation ACI, offering a simplified way to deliver cells2

MACI has established results from the SUMMIT trial and 5-year long-term extension.3,4

MACI has accrued nearly 10 years of clinical experience.5

MACI is the only biologic knee cartilage therapy to gain FDA approval through the Biologics License Application.6

MACI results have been reported in a growing body of literature, including nearly 50 publications and 5 randomized controlled trials.7

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References: 1. Pettit RJ, Everhart JS, DiBartola AC, Blackwell RE, Flanigan DC. Time matters: knee cartilage defect expansion and high-grade lesion formation while awaiting autologous chondrocyte implantation. Cartilage. 2021;13(suppl 2):1802S-1808S. 2. Flanigan DC, Sherman SL, Chilelli B, et al. Consensus on rehabilitation guidelines among orthopedic surgeons in the United States following use of third-generation articular cartilage repair (MACI) for treatment of knee cartilage lesions. Cartilage. 2021;13(suppl 1): 1782S-1790S. 3. Saris D, Price A, Widuchowski W, et al; SUMMIT study group. Matrix-applied characterized autologous cultured chondrocytes versus microfracture: two-year follow-up of a prospective randomized trial. Am J Sports Med. 2014;42(6):1384-1394. 4. Brittberg M, Recker D, Ilgenfritz J, Saris DBF; SUMMIT Extension Study Group. Matrix-applied characterized autologous cultured chondrocytes versus microfracture: five-year follow-up of a prospective randomized trial. Am J Sports Med. 2018;46(6):1343-1351. 5. MACI® (autologous cultured chondrocytes on porcine collagen membrane) Prescribing Information. Cambridge, MA. Vericel Corporation; 2025. 6. Gudeman AS, Hinckel BB, Oladeji L, et al. Evaluation of commercially available knee cartilage restoration techniques stratified by FDA approval pathway. Am J Sports Med. 2022;50(13):3598-3704. 7. Hadley CJ, Shi WJ, Murphy H, Tjoumakaris FP, Salvo JP, Freedman KB. The clinical evidence behind biologic therapies promoted at annual orthopaedic meetings: a systematic review. Arthroscopy. 2019;35(1):251-259.

Indication and Important Safety Information

Important Safety Information

Contraindications: MACI is contraindicated in patients with a known history of hypersensitivity to gentamicin, other aminoglycosides, products of porcine or bovine origin; in patients with severe osteoarthritis of the knee, inflammatory arthritis, inflammatory joint disease, or uncorrected congenital blood coagulation disorders; in patients who have undergone prior knee surgery in the past 6 months, excluding surgery to procure a biopsy or a concomitant procedure to prepare the knee for a MACI implant; or in patients unable to cooperate with a physician-prescribed post-surgical rehabilitation program.

Warnings and Precautions:
  • Malignancy: The risk of MACI in patients with malignancy in the area of cartilage biopsy or implant is unknown. Expansion of malignant or dysplastic cells present in biopsy tissue during manufacture and subsequent implantation may be possible.
  • Transmissible infectious diseases: Because patients undergoing procedures associated with MACI are not routinely tested for transmissible infectious diseases, cartilage biopsy and MACI implant may carry risk of transmitting infectious diseases.
  • Presurgical Comorbidities: Local inflammation or active infection in the bone, joint, and surrounding soft tissue, meniscal pathology, cruciate ligament instability, and misalignment should be assessed and treated prior to or concurrent with MACI implantation.
  • Product Sterility: Final sterility test results are not available at the time of shipping.

Adverse Reactions: The most frequently occurring adverse reactions reported for MACI (≥5%) were arthralgia, tendonitis, back pain, joint swelling, and joint effusion. Serious adverse reactions reported for MACI were arthralgia, cartilage injury, meniscus injury, treatment failure, and osteoarthritis.

Specific Populations:
  • Use of MACI in pediatric patients (younger than 18 years of age) or in patients over 65 years of age has not been established.
  • The MACI implant is not recommended during pregnancy. For implantations post-pregnancy, the safety of breastfeeding to an infant has not been determined.

To report negative side effects, contact Vericel Corporation at 1-800-453-6948 or FDA at 1-800-FDA-1088 (1-800-332-1088) or www.fda.gov/medwatch.

Please see Full Prescribing Information.

Indication

MACI® is an autologous cellularized scaffold product indicated for the repair of single or multiple symptomatic, full-thickness cartilage defects of the knee with or without bone involvement in adults.

MACI® (autologous cultured chondrocytes on porcine collagen membrane) is an autologous cellularized scaffold product indicated for the repair of single or multiple symptomatic, full-thickness cartilage defects of the knee with or without bone involvement in adults.

Limitations of Use

Effectiveness of MACI in joints other than the knee has not been established.

Safety and effectiveness of MACI in patients over the age of 55 years have not been established.