Step-By-Step Guide of Procedure & Rehabilitation | MACI® Skip to content

A step-by-step guide to the MACI procedure

MACI instrumentation is designed to support the delivery technique you choose.

MACI Arthro instrumentation is designed to create a reproducible technique for arthroscopic delivery while maintaining cell viability on the implant.3

With a range of Cannula, Cutter, and V-shuttle sizes to address accessible defects of the knee that are ≤4 cm2, MACI Arthro instruments are packaged separately to provide surgeons with the option to select the appropriate tools for each case. Ask your MACI Representative for more information.

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

View the MACI Arthro Instrument Symbols Glossary 

MACI Open Instruments

MACI Open instrumentation is intended to assist with delivery of MACI via mini-arthrotomy. Ask your MACI Representative for more information.

Important note: MACI Open instrumentation 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 the MACI Open instrumentation instructions for use, including individual instrument instructions for use.

MACI can be delivered to a wide range of knee cartilage defects via mini-arthrotomy and can now be delivered arthroscopically in patients with ≤4 cm2 accessible defects

Condyle

Condyle Defect
Condyle Debridement
Condyle MACI Implantation

Trochlea

Trochlea Defect
Trochlea Debridement
Trochlea Implantation

Patella

Patella Defect
Patella Debridement
Patella Implantation

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

Achieve routine

0–3 months

0-3 Months Achieve Routine Icon

After the immediate post-surgery phase, patients should be able to 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

3-6 Months Build Strength Icon

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

6-9 Months Be Active Icone

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

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 that expands to fill the defect.2

Cartilage Matrix Before and After MACI Implantation

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.

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References: 1. Data On File (design history files 21-087-TR and 21-081-TR). 2. 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. 3. 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.

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.