GL - some good advice above... another idea - do pilates - a lot of the moves will be off your feet and that way you are building core strength, which a lot of times effects our balance and prevents injuries by providing stability and balance. I use neoprene braces for my knees, which act up from time to time - I agree they are very good for keeping the joint warm so when you're working out it prevents further injury, however I think you need to focus on letting that baby heal first. Doctor knows best...follow their orders! This is also an excellent time to work on your upper body strength. When you're starting out, you should strength train 3 days a week, 3 sets of light weight doing 12 reps a set. Once your form is solid, about a month later, you can then start doing less reps and higher weight for strength purposes. Hope you don't give up on the exercise challenge... this is just a good time for you to look at a new door opening bc when you're back on your feet, imagine... you'll be farther ahead then where you left off!
JP