Severe damage to the anterior cruciate ligament (ACL) of the knee often requires reconstructive surgery. The surgeon uses graft tissue taken from a donor bank (called an allograft) or harvested from the patient (an autograft).
As you have discovered, the reported failure rate for this surgery is as high as 20 per cent. That’s one out of every five patients — an unacceptable level for any surgeon. The reported range is from zero to 20 per cent, so clearly there must be some reasons for this wide range.
Some experts suggest the problem is with the terminology. What “failure” means to one surgeon may not be the same to the next. There isn’t a uniform, agreed upon definition that is used by everyone reporting their results in the literature.
Some surgeons use the results of clinical tests to determine failure based on instability. For example, the joint moves too much from front to back or side to side when pressure is applied. Or measurements from a special tool called the KT-1000 arthrometer show there’s a problem. Others stand by MRI documentation that shows a re-tear.
Taking a closer look at the studies published on this topic, there seems to be about a 12 per cent failure rate for allograft tissue. It’s possible that some specific factor about the allograft is responsible for a portion of these failures. But exactly what that might be remains unknown. It could be the age of the donor at the time of death. It could be the way the donor tissue is processed and stored.
More study is needed before we can pinpoint all the reasons why graft failure occurs. The real key may be to find a surgeon who has a low failure rate. Discussing your concerns with your surgeon may also help reduce your anxiety in this area. It is a real concern and not one that surgeon or patient should take lightly.