What is MICAS?

What is MICAS?

MICAS stands for minimally invasive computer-assisted surgery. It is a combination of doing knee replacement that way includes a minimally invasive (subvastus) tissue approach to decrease tissue damage and early recovery and a computer-assisted navigation system to accurately place components that reduce error and long-term satisfactory outcomes.

What is the subvastus approach?

In this approach, no muscle is cut to reach the knee, and hence there is no weakening of the muscle; there is minimal pain and bleeding; and the need for physiotherapy is drastically reduced or eliminated altogether. This approach was described in the German language over 100 years ago but was described first in the English language in 1999. We use exclusively this approach in all our patients except some contraindication when this can’t be used.   

What are the advantages of the subvastus approach?

In the conventional para-patellar approach, the quadriceps muscle around the patella splits and is stitched together at the end of surgery. So in the postoperative recovery period, when physiotherapy started while doing knee bending, the patient had a sense of stretching muscles and pain. But in subvastus, because quadriceps are spared, the patient can bend the knee from the first day on by himself or herself. And independent walking has been possible since the first day.

What is computer-assisted navigation, and how will it help?

In computer-assisted surgery, a navigation device is used that has a sensing camera. In intraoperative patients, different anatomical bony landmarks are recorded. According to those landmarks, a computerised bone model was created, and sensors took data and showed accuracy and measurements of bone cuts, gap balance, and component positions.

The use of computer-assisted navigation allows for more accurate and reproducible restoration of mechanical axis and component positioning. Better alignment should lead to an improved functional outcome and an increased long-term survival of the prosthesis.

We are currently using the OrthoMap precision image-free navigation system of a USA-based Stryker company.