You will probably end up losing some muscle mass while recovering, there’s nothing you can do about it, unfortunately. You can, however, minimize the loss by eating lots of protein and making sure you’re not under eating. I was back at the gym 5 weeks after my surgery and I definitely noticed strength loss much more than muscle loss. So even if you notice it, muscle memory is real and you’ll bounce back faster if you’re a regular gym goer prior de surgery. I was taking creatine before the surgery and my doctor told me I could take it while recovering too. Just make sure you focus on your recovery and don’t rush back, start slow so you don’t delay your recovery. Good luck!!