Can you have a knee replacement with out a tourniquet? Yes you can.
Tourniquets are like blood pressure cuffs on your thigh that decrease blood flow to the knee. This is done so that the surgeon can see the field with minimal blood in the surgical field. Sometimes however the tourniquet can cause issues. Imagine a blood pressure cuff on your arm for an hour or so. Imagine how you feel when the blood pressure cuff is inflated for just a few seconds on your arm.
A March 22, 2019 study published in the Archives of Orthopedic and Trauma surgery showed that patients who had surgery without the tourniquet had:
How can you get a knee replacement without a tourniquet? You need an experienced surgeon with this surgery and you need a method to control blood loss and visualization of the field. Not everyone is a perfect candidate for this surgery so check with your doctor.