Suggest Treatment For Severe Knee Pain Despite Taking Cortisone Injection

I know I have severe osteoarthritis of bilateral knees, with my left knee bothering me more than my right. I m on disability from being an RN. Last October, while doing the cool down in water aerobics, I was doing a modified exercise when I got a severe pain in the lateral side of my left knee. Within a month, it had swelled, and I saw my family doctor. She instructed me to see my orthopedist. By this time my L knee was double what my right knee was. I was given a cortisone injection. Several days after the injection, my knee really hurt as the medication moved around my knee. My knee continues to swell. At times it locks. I have a hot and cold wrap I ve been using on it, as well as taking Mobic. I take OTC acetomenifphen for additional pain. What do you recommend?