Question on realistic muscle weight

I had a hip replacement in January. In the last few years I was moderately active, structured workouts of both cardio and weights 2-3x per week, but the 6-8 months before surgery I was on medical restrictions and only allowed to do some physical therapy exercises that were very light compared to my previous routine. First couple months after surgery I was only focused on regaining normal movement, range of motion, and weight bearing again.

Now that I’m 6 months out, I am still working very closely with PT and have a good 45 min workout every day that includes some cardio, body weight exercises, and some very light weights. I do this at least 4x a week, 5 or 6 if I’m feeling good.

I have only just started weighing myself and tracking calories again. My clothes fit better, I am stronger, and my body looks very different in a good way, but I am only 4lbs down from my weight the week before surgery. I have lost about 4 inches off my hips and 2 off my waist. I’m very happy with my progress and surgical recovery overall, but I feel like this is more than 4lbs of difference.

Is it realistic that I would have gained significant muscle that is accounting for only a few lbs difference on the scale? I don’t have access to a good body composition scanner, and didn’t do one prior to surgery so I don’t know that it matters much. I know a lot changes with the muscles around my hip, but I feel like I haven’t been lifting heavy amounts of weight to have significant muscle gains to account for potentially 10-15lbs of fat loss that I feel would equate to the amount of inches off my belly.