New knee , yoga kneeling , pressure

Hi , I’m Samantha , I am 54 and have been doing yoga for 6 years , it has become one of the reasons I wake up !! I love it , but I have osteoarthritis and have just been diagnosed with fibromyalgia .
I have had operations on both knees and have been putting off having a new right knee , I have heard or I have read that when you have a new knee you can’t kneel up again , I use knee pads already in my practice , i cannot imagine not being able to do yoga .
The last cartilage operation I had I think about 10 years ago , was made worse when my specialist cut ligaments ?? Across my knee cap ? And I now can only bend my knee 90 degrees , so I’m unable to do child’s pose , struggle with warrior 1and 2 but do my best , I’ve joined here to see if there is any one who loves yoga as much as I do who has had a knee replacement ? , would be interested to hear if you can put pressure on your knee ? Or any advice , thank you