Autologous Chondrocyte Implantation (MACI)

Matrix-induced autologous chondrocyte implantation (MACI) is a new procedure to treat the articular cartilage defects of the knee. Articular cartilage is a tissue that covers the surface of the joints and is responsible for pain-free movement of the bones within the joint. If the articular cartilage is damaged, the ends of the bones rub against each other causing pain. Matrix-induced autologous chondrocyte implantation is indicated for patients with significant cartilage defects causing joint pain, swelling, and catching in the knee.

Matrix-induced autologous chondrocyte implantation is a two-step procedure. The first step is performed arthroscopically, where the healthy cartilage cells or chondrocytes is harvested from the non-weight bearing area of the bone. The chondrocytes are sent to the laboratory where the cells are cultivated on a sterile collagen membrane (matrix) for 4 to 6 weeks.

The second stage procedure is performed through an open procedure or arthrotomy. A small incision is made to expose the area of cartilage damage. The chondrocyte cells that have been seeded onto the collagen membrane are implanted into defected area in the knee. The MACI procedure helps in regeneration of cartilage and brings back the flexibility of the knee.

Following MACI procedure, you may not be allowed to lift heavy things or bear weight on the area of the cartilage for at least 6-8 weeks, so that the cells adhere to the underlying bone. A knee brace is worn to protect the cartilage repair. Physical therapy may be recommended to strengthen quadriceps and hamstring muscles.

You will be allowed to return to your sports after a year. Jogging or running is not advised until 6 months. Some sports such as swimming and cycling can be started after 6 months and you will not be allowed to play high impact sports for 1 year. You can return to your work from two to six weeks after surgery.

  • NYU Langone Hospitals link
  • NYU Langone Health link
  • American Academy of Orthopaedic Surgeons link
  • Arthroscopy Association of North America link
  • American Orthopaedic Society for Sports Medicine link
  • American Shoulder And Elbow Surgeons link