You can always reschedule a surgery -cannot go back once it's done. If I were you & getting better with therapy then I would cancel & see how things go. Worst case scenario the knee doesn't get better or starts to get worse & you go into surgery 100% sure it is the best option, rather than how you are felling now. MRIs have been wrong & should NEVER replace a good exam. If an exam doesn't produce a positive drawer test I would believe that over an MRI. Go with your gut & stick with rehab. Just my opinion, but if I could go back to before surgery #1 I would never do it again. Best of luck to you.