MACI Knee Treatment
What Is MACI Knee Treatment?
MACI, which stands for Matrix-Induced Autologous Chondrocyte Implantation, is an advanced, two-stage cartilage restoration procedure that uses a patient’s own cartilage cells (chondrocytes) to repair a damaged area of the knee joint. Because it uses the patient’s own cells, MACI produces a repair tissue that behaves more like natural cartilage than some of the older cartilage treatment techniques.
When Is MACI an Option?
MACI is generally considered for patients with:
- A well-defined, focal cartilage defect on the femur (thighbone) — typically larger defects that aren’t ideal candidates for microfracture alone
- Persistent pain, swelling, or mechanical symptoms despite nonsurgical treatment
- Overall healthy, well-aligned knee mechanics, since significant malalignment or ligament instability typically needs to be corrected either before or at the same time as MACI for the repair to succeed
- A commitment to a longer, more structured recovery process, since MACI is a two-stage procedure performed months apart
How Is MACI Performed?
MACI is completed in two separate stages:
- Biopsy stage — during an initial arthroscopic procedure, a small sample of healthy cartilage is harvested from a lower-weight-bearing area of the patient’s knee. This tissue is sent to a specialized lab, where the cartilage cells are extracted and grown over several weeks, expanding into millions of new cells seeded onto a collagen membrane.
- Implantation stage — several weeks later, in a second surgery (usually performed through a small open incision rather than purely arthroscopically), the cultured cell membrane is precisely trimmed to match the shape of the cartilage defect and secured into place, often with a specialized fibrin glue, allowing the new cells to mature into cartilage tissue over time.
Coast your way to recovery
Dr. Palsis utilizes innovative treatment techniques to get you back in motion and back to the life you love.
Recovery After MACI
MACI has one of the more gradual recovery timelines among knee cartilage procedures, since the newly implanted cells need significant time to mature into durable cartilage:
- An initial period of protected, limited weight-bearing, often for 6 or more weeks
- Continuous passive motion is frequently used early on to help the graft mature properly
- Physical therapy progresses slowly and deliberately over many months
- Return to impact sports is typically not considered until 12 months or later, reflecting the biological reality that new cartilage takes considerably longer to mature and strengthen than tissues like tendon or bone
While the recovery is a longer commitment, MACI is designed to offer durable, long-term results for the right candidate with a significant cartilage defect.
Get back to what moves you
Dr. Palsis specializes in the treatment of knee, shoulder, and sports injuries.