Wearing a medical boot for broken foot bone.

Sounds like maybe the boot is too big or something. I was just in one for 10 weeks for a broken ankle, used crutches for 6 of those weeks and did not have that much stress on other knee or hip.
You should talk to the Dr. about it.

Just in case anyone is still asking this question, yes, there is a product which will help you--Evenup. It is an adjustable piece that you slip over your other shoe so that the height of the other shoe is the same as the medical boot. It cost about $30 but is well worth the expense.