I don't want to beat a dead horse......

but I will anyway.  Here's a quote from this article from Arthritis Today about prehab.www.arthritistoday.org/treatments/surgery/prehab-for-surgery.php

Fifty percent of outcome success is due to the surgeon, and the other 50 percent is due to the patient’s commitment to recovery – starting with pre-hab,” says Vonda Wright, MD, assistant professor of orthopedic surgery at the University of Pittsburgh’s Center for Sports Medicine.

It is recommended to start exercises 6 weeks prior to knee surgery.  I imagine that most of us have been involved in physical therapy prior to making this decision.  If so, time to pull out all those exercises and do them faithfully.  If you haven't had previous physical therapy, there is a link in the above article for exercises to do prior to surgery.