MACI Procedure

If you struggle with symptomatic cartilage lesions in your knee, osteochondral injuries or defects, or painful cartilage degeneration that causes pain, you could be a candidate for matrix-induced autologous chondrocyte implantation (MACI). This article explains what the MACI procedure is, who is a suitable candidate for the procedure, what recovery is like, and the results you can expect.

MACI procedures are being done at Brotzman Sports Medicine in Austin, Texas. If you would like to know more, give us a call today!

S. Brent Brotzman, MD

Orthopedic & Sports Medicine Specialist located in Austin, TX

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What is Matrix-induced Autologous Chondrocyte Implantation (MACI)?

Matrix-induced autologous chondrocyte implantation (MACI) is a surgical procedure that utilizes a patient’s cartilage cells to regrow new cartilage. This cartilage is then used to repair a cartilage defect in the knee joint.

The procedure involves two steps. First, the surgeon will take a cartilage biopsy using knee arthroscopy. The cartilage will then be sent to a lab to grow.

The next step is to take the cartilage implant and cut it to size to fit perfectly in the knee. During recovery, the cartilage cells will grow and strengthen inside the knee.

The MACI procedure can be used on the following areas of the knee:

  • The medial femoral condyle
  • The lateral femoral condyle
  • The patella
  • The trochlea

Who is a Candidate for MACI?

If you have symptoms of cartilage damage or patellar instability that has caused degeneration of cartilage in the knee, then you may be a good candidate for the MACI procedure.

Symptoms of cartilage damage include the following:

  • Sharp or dull pain in the front of the knee
  • Pain worsens after a period of sitting or climbing stairs

Symptoms of patellar instability include the following:

  • Your kneecap is coming off its track and dislocating

Dr. Brotzman will perform a thorough diagnosis to determine if you have cartilage damage that warrants the MACI procedure. He will perform a physical examination as well as magnetic resonance imaging (MRI) to see the extent of the cartilage injury.

What Happens During the MACI Procedure?

The MACI procedure involves two steps. In the first step, your surgeon will make two portals on either side of your knee, which he will use to insert a tiny camera and his instruments. The camera allows your surgeon to see the condition of the cartilage inside your knee.

At this point, your surgeon may debride, or remove damaged tissue from your knee. The surgeon will then take a cartilage biopsy. This whole process will take around 30 minutes.

The biopsy will then be sent to the lab, where it will grow on a collagen matrix for about a month. This will give stability to the cartilage before it is inserted back into the knee.

The second step is to place the MACI implant into the knee. First, your surgeon will cut the new cartilage to the exact size of the defect in your knee. Then, the surgeon will glue the implant in place. The whole process takes about an hour and will require a two-inch incision in the knee.

What is Recovery from MACI Surgery Like?

There will be a recovery period after both stages of MACI surgery.

Stage 1

You will be able to return home on the same day of your knee surgery. Weight-bearing is possible, but there may be some discomfort. You may use crutches, but most patients can usually walk without them after a few days. You should probably be able to return to work after a day or two.

Stage 2

You will be able to return on the same day of surgery. At the end of the procedure, your surgeon will put your leg in a straight-locked brace. You will continue to wear this for 6 weeks.

During this time, you may be able to bear weight on your leg, though there may be some discomfort. You will also be able to unlock the knee brace while sitting.

During recovery, you will use a continuous passive motion machine (CPM). This will help minimize scar tissue and help the cartilage to grow evenly. You will usually begin physical therapy between 4-6 weeks after surgery.

What Results Can I Expect from MACI Surgery?

If you are a good candidate for MACI, you can expect to see a good improvement in knee pain and function after receiving MACI treatment. You should speak with your surgeon about any specific goals you have. However, most patients can return to sports and activities that they previously enjoyed.

Schedule Your Appointment Today

Schedule your appointment at Brotzman Sports Medicine to learn more about how MACI can help you. Dr. Brotzman is helping many patients throughout Austin, TX to return to the activities they love. Contact us today!


Words from our patients