My 4 year old boxer had ACL surgery. Can an infection cause scar tissue to grow?

Apparently scar tissue has grown over the nerve to the foot and she can not walk after 7 weeks. The infection was just discovered 1 week ago by the 3rd vet used. She is on antibiotics, but I am being told she must have surgery to remove the scar tissue to relieve the pressure in hopes the nerve is not too damaged. Another surgery, pain and suffering for the dog and another very expensive bill I cannot afford. Was there negligence? Should the 2 vets I took her to have spotted the infection. Did the infection cause the scar tissue to expand encircling the nerve causing it not to work? Answers would be great or where to look for them would also be helpful. Thanks