For muscle loss? Doubt it. SIL was doing exercises the day after her surgery. With a 90 degree cast, no exercise can be done on the many of the muscles.

I lost my medialis quad activation completely for 6 weeks after ACLR surgery. It took 6 months of PT to get my patella to track straight afterwards, and it still isn't quite right.

After being in a cast when I was 13 for 6 months, I lost quad size that I never regained, even after 40 years of trying. You can easily see the difference with the eye.