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See the MACI procedure

Autologous chondrocyte implantation, simplified1

A short video that may help your patients

This video details Jo’s journey from injury through diagnosis and discussions with her doctor, to rehabilitation and a renewed sense of success. Watch now and share it with your patients.

A step-by-step guide to the MACI procedure

MACI is appropriate for a wide range of knee cartilage defects


Condyle cartilage defect
Condyle cartilage debridement
Condyle MACI implantation


Trochlea cartilage defect
Trochlea cartilage debridement
Trochlea MACI implantation


Condyle cartilage defect
Condyle cartilage debridement
Condyle MACI implantation

Over the course of a year, the matrix continues to expand and fill the cartilage defect.2

After implantation, chondrocytes migrate from the MACI membrane and adhere to the subchondral bone forming new cartilage.3 As the matrix matures, it produces a durable repair tissue which expands to fill the defect.2

Before and after MACI procedure

Simplify the MACI procedure with the MACI Surgical Implantation Kit

The MACI Surgical Implantation Kit is intended to assist with MACI knee surgery. The MACI Surgical Implantation Kit is provided by Vericel for MACI procedures. Ask your MACI Representative for more information.

Important note: The MACI Surgical Implantation Kit is not available or appropriate for all MACI procedures. The content presented here is for informational purposes only and does not constitute medical advice.

Download MACI Surgical Implantation Kit Instructions for Use, including individual instrument Instructions for Use

MACI implantation kit

A closer look

Customizing the MACI Implant for an exact fit

The following is an overview of the progression for rehabilitation from MACI*

Achieve routine

0–3 months

Achieving a routine

After the immediate post-surgery phase, patients will work towards a pain-free and full passive knee extension with limited weight bearing. Over time, the goal is to be free of ambulation devices and knee braces while becoming thoroughly independent with rehabilitation exercises.

Functional goals include:

  • Mobile with crutches within first week
  • Limited weight bearing and pain-free, full knee extension by 2-3 weeks
  • Independent home exercise as early as 1 month
  • Full weight bearing and full knee range of motion by 8-12 weeks post-surgery
  • Free from knee brace by 8-12 weeks post-surgery

Build strength

3–6 months

Building strength

During this phase, patients should begin to feel comfortable returning to recreational activities. An exercise program will help re-build muscle strength and endurance. Patients may feel ready for more strenuous activity, so you may need to give explicit direction on what activities they are ready for at this stage.

Functional goals include:

  • Full and pain-free weight bearing and range of motion
  • Continue progression of strengthening exercises without pain or swelling
  • Transition to gym/home based rehab
  • Free from crutches

Be active

6–9 months

Being active

Patients should be able to enjoy a return to recreational activities and sports by gradually increasing the difficulty of their exercises. Every patient’s recovery is unique and should be guided by your assessment of graft maturation as well as mental preparedness of the patient and the general physical function and level of specific knee strength, stability, and support.

Functional goals include:

  • Increase distance, time, and difficulty of exercises
  • Ability to tolerate lengthy walking distances
  • Return to a pre-operative level of activity

Tissue phases during MACI rehabilitation

Cartilage repair rehab phase - 0-3 months

0–3 months

Implantation & protection

Cells adhere to bone and begin to proliferate throughout the defect

Cartilage repair rehab phase - 3-6 months

3–6 months

Transition & proliferation

Continued proliferation forms a defect-spanning matrix

Cartilage repair rehab phase - 6-9 months

6–9 months

Remodeling & maturation

Expansion of the cell matrix into puttylike consistency, progressive hardening until durable repair tissue forms

9+ months after MACI

“I’m close to being back to the best shape of my life and keep improving every day. I have been able to get back to all the physical activities I love doing, like running, squatting, jumping, lunging, weight lifting, taking fitness classes, boxing, hiking, and camping.”

Chris, MACI patient

Paid testimonial by a MACI patient.

*Recovery time varies greatly as no two patients are alike. The goal is to restore optimal function in each patient as safely as possible. These timeframes are not universal and should be used for general guidance on which goals to reach before progressing to the next. MACI is contraindicated in patients who are unable to follow a physician-prescribed post-surgical rehabilitation program.

Timelines are based on clinical observations and should not be considered medical advice. Individual results for activity and repair tissue progress will vary.

Recovery from MACI treatment is highly individualized. The rehabilitation program is tailored specifically to each patient’s unique goals and objectives. Everyone heals at their own rate and cartilage will continue to mature over time. Patients should return to heavy impact activities such as cutting or pivoting as directed.

MACI app

Introducing a customizable app to enhance your patient’s recovery.

Encourage your patients to download the My MACI App to help them prepare for the MACI procedure and to get personal guidance through their rehabilitation program.

Apple App Store logo

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Help your patients understand what life could be like with MACI

Watch and share the video 

Do you have patients interested in talking with real MACI patients about their experience?

The MACI Mentor Program gives patients considering MACI an opportunity to connect one-on-one with real MACI patients by phone.

It's Your Move

Encourage your patients to speak with a MACI Mentor at 1-888-237-5493 or visit

Reference: 1. Gooding CR, et al. A Prospective, Randomised Study Comparing Two Techniques of Autologous Chondrocyte Implantation for Osteochondral Defects in the Knee: Periosteum Covered Versus Type I/iii Collagen Covered. Knee. 2006: 13(3): 203-210. 2. Saris D, Price A, Widuchowski W, et al. for the 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;42:1384-1394. 3. Brittberg M. Cell carriers as the next generation of cell therapy for cartilage repair: a review of the matrix-induced autologous chondrocyte implantation procedure. Am J Sports Med. 2010 Jun;38(6):1259-71.

Indication and Important Safety Information

Important Safety Information

MACI is contraindicated in patients with a known history of hypersensitivity to gentamicin, other aminoglycosides, or products of porcine or bovine origin. MACI is also contraindicated for patients with severe osteoarthritis of the knee, inflammatory arthritis, inflammatory joint disease, or uncorrected congenital blood coagulation disorders. MACI is also not indicated for use 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.

MACI is contraindicated in patients who are unable to follow a physician-prescribed post-surgical rehabilitation program.

The safety of MACI in patients with malignancy in the area of cartilage biopsy or implant is unknown. Expansion of present malignant or dysplastic cells during the culturing process or implantation is possible.

Patients undergoing procedures associated with MACI are not routinely tested for transmissible infectious diseases. A cartilage biopsy and MACI implant may carry the risk of transmitting infectious diseases to healthcare providers handling the tissue. Universal precautions should be employed when handling the biopsy samples and the MACI product.

Final sterility test results are not available at the time of shipping. In the case of positive sterility results, health care provider(s) will be contacted.

To create a favorable environment for healing, concomitant pathologies that include meniscal pathology, cruciate ligament instability and joint misalignment, must be addressed prior to or concurrent with the implantation of MACI.

Local treatment guidelines regarding the use of thromboprophylaxis and antibiotic prophylaxis around orthopaedic surgery should be followed. Use in patients with local inflammations or active infections in the bone, joint, and surrounding soft tissue should be temporarily deferred until documented recovery.

The MACI implant is not recommended during pregnancy. For implantations post-pregnancy, the safety of breast feeding to infant has not been determined.

Use of MACI in pediatric patients (younger than 18 years of age) or patients over 65 years of age has not been established.

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.

Please see Full Prescribing Information for more information.


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

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

MACI is intended for autologous use and must only be administered to the patient for whom it was manufactured. The implantation of MACI is to be performed via an arthrotomy to the knee joint under sterile conditions.

The amount of MACI administered is dependent upon the size (surface in cm2) of the cartilage defect. The implantation membrane is trimmed by the treating surgeon to the size and shape of the defect, to ensure the damaged area is completely covered, and implanted cell-side down.

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.