The most common way to repair a damaged anterior cruciate ligament (ACL) in the knee is by grafting tissue to take the place of the original ligament. In one type of repair, a section of tissue is taken from the patellar tendon. This involves using a plug of bone from the femur (thighbone) and a length of tendon and another plug of bone from the patella (kneecap). The graft tissue can come from the patient or from someone else. Graft tissue from the patient is called an autograft. Graft tissue from someone else is called an allograft
Is one type of graft tissue better? To find out, an orthopedic surgeon evaluated 25 of his autograft patients and 28 of his allograft patients to see if one group did better than the other. Over a five-year period, both groups fared about the same. There was a slight trend toward looseness in the allograft group. Those with the autograft showed more difficulty getting the knee fully straight. In both cases, the differences were small and did not significantly limit the use of the knee.
So which kind of graft should a patient undergoing an ACL reconstruction receive? The five-year results aren’t the only factor to consider. An autograft requires taking a small plug of bone and tendon from the thigh and kneecap during the ACL reconstruction. Taking a section of the patellar tendon can cause increased pain, fractures of the kneecap, tendon inflammation, and formation of scar tissue. The procedure can also lead to problems in the timing and strength of the quadriceps muscle on the front of the thigh.
Allograft procedures have their own set of problems. Difficulties may include the availability of donor tissue, the cost of donor tissue, and whether the body will reject the graft after surgery. It is also remotely possible for patients to get diseases such as HIV and hepatitis from an allograft. However, the chances are very low. The statistical risk of getting HIV and hepatitis from an allograft is only about one in 1,600,000. In fact, there have been no reported cases of HIV or hepatitis transmission from allograft tissue since donor testing became available in the 1980s.
Deciding what type of graft tissue to use in an ACL reconstruction is an issue for doctors and patients to discuss. The good news reported in this study is that either choice results in similar overall improvement.