Hi I Have An Menusious Tear In My Knee And

hi I have an menusious tear in my knee and cannot straighten my leg, now my back is also in agony and I am having to uses crushes as I cannot walk for long periods. I've had chronic back pain for 27 years and I work full time as a carer. I am off work at the moment waiting for surgery is there any thing that can help my back or is this AS Ankolsing Spondilitis. I cannot sit or stand for long periods and I am on 11 tablets a day. Will I be able to return fulltime work or will my back and knee get worse. Thanks Siobhan