Thank you for love and concern for this squirrel. I know its hard to watch as she struggles up/down the fence.
In my yard, we had a fox squirrel with a mangle/twisted foot & toes (called him Noodle). I remove one fence board to make a hole so he could run through instead of climbing up/down (neighbor was friendly about me doing it). Within 1 day, all squirrels knew this secret passage and started using it. (If you read my posting, Ms. Mo was another injured squirrel who loved the secret passage.)
In your case, I just worry about constant movement which doesn't give time to heal.
Thank you for helping this squirrel.
Mr.SSG