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Are the remaining staples in place? Is the surgical incision clean and dry? Is there any localized heat/pain/swelling? Are you using an elizabethan collar to keep your dog from being able to chew at the incision? To be safe, I would suggest having your dog's knee incision examined sooner than later, to make sure there is no sign of active dehiscence. In the meantime, I want to reiterate that you keep your dog as quiet at home as possible, as orthopedic surgeries require this for proper healing.
Keep her cone on, maybe tighten her collar. If necessary, place her in a crate, to keep her quiet for the night. The staples still being in and the incision being dry are good things. Tomorrow, contact your vet, and have them take a look at the incision.
You don't need to actively do anything at the moment. Just keep it clean and dry. If it happens to get wet, dry it off gently with a clean towel. If it's raining outside, and you're worried about the rain, you can always wrap her leg up with a large plastic bag if necessary to keep the incision from getting wet. Do not cover it up with gauze or band-aids, as you suggested, as you might accidentally introduce bacteria this way.
It sounds like you're doing a good job monitoring your dog's surgical incision. Please let me know if there's anything else you would like to ask me. If you're satisfied with my answers and help, please feel free to give me a good rating. If you are still uncertain about what to do, please let me know. Cheers.