Why is my knee, 3 weeks after surgery for Septic Arthritis, hurt now more then ever? I believe the muscle spasms are causing the pain, but idk. Help!

Septic arthritis. Healing from either septic arthritis or knee surgery often is slow; this doesn't sound abnormal. Septic arthritis also risks cartilage or bone damage that can be permanently painful. However, persisting or recurrent infection is always possible, especially if there is increasing redness or swelling, so don't take chances. Follow up ASAP with the doctor(s) treating you. Good luck!
Many concerns. the procedure would be expected to return you to baseline Continued pain requires a follow-up examination.