Your surgeon will do a detailed exam including physical tests and X-rays. Range of motion, strength, and joint laxity will all be carefully assessed. Most often, the patient is classified as Grade I, II, III, and IV. These grades guide the surgeon in planning and carrying out the second (revision) surgery.
For example, grade I is a simple repair. It is much like the original surgical procedure. New tunnels are drilled through which the graft tissue is inserted and sutured in place. The most common reason for graft failure is malposition of the original tunnels.
For grades II and III, bone grafting may be needed. The operation is often done in two or three stages (depending on what needs to be done). Grade IV revision surgery is more complex with multiple surgical steps.
There may be bone grafting, ligament reconstruction, and possibly an osteotomy required. An osteotomy is the removal of a wedge-shaped piece of bone that is then reinserted to correct a malposition of the knee.
The surgeon will still need to harvest tendon tissue to replace the graft that failed. This can come from the knee being operated on or it can be harvested from the other knee. There are several choices with pros and cons for each one.
Your surgeon will probably go over all the details with you. Let him or her know of your interest in the proposed procedure.