Autograft versus Allograft For ACL Reconstruction

Allografts Have Higher Overall Failure Rates

Although some papers have shown identical autograft versus allograft failure rates, our Meta-analysis [1] published in the July 2007, Knee Surgery, Sports Traumatology, Arthroscopy showed that the literature has found there to be an overall three times higher failure rate for allografts versus autografts.

High Allograft Failure Rates References

Other recent studies have also shown the higher incidence of failure in allografts than autografts.

PAPER 1: 23.1% failure rate from the University of Kentucky from Dr Singhal, et al [2] using fresh-frozen anterior tibialis tendon allograft. They had a failure/reoperation rate of 55% in patients under 25 years of age.

PAPER 2: 21% failure rate from Dr Michael Grafe and Dr Peter Kurzweil [3] using fresh-frozen, irradiated Achilles tendon allograft.

MEETING PRESENTATION 3: 23.4% failure rate in young athletes from Dr Eugene Barrett’s group using fresh-frozen bone-patella-tendon-bone allograft. Summary of presentation published in the AAOS Now (the American Academy of Orthopaedic News bulletin): Young athletes have high failure rate with allograft ACL By Annie Hayashi [4].

Allografts Have Higher Infection Rates

The Centers for Disease Control (CDC) studied the infection rates at a surgicenter in California [5]. They found autografts to have a zero percent infection rate. They found irradiated allografts to have a zero per cent infection rate, however most surgeons do not use irradiated grafts because the radiation weakens them and predisposes them to failure. They found a 4% infection in non-irradiated allografts. Grafe and Kurzweil’s paper cited above [3], had a 4% infection rate even though they used irradiated grafts.

Risks of Disease Transmission With Allografts

Although the risks of disease transmission with allografts is very low, it does exist. Rigorous screening of donors should eliminate most of the risk. Testing of donor tissue should catch most of the rest of the cases of infected tissue. However, there is a window where testing is negative and yet disease is present. There are also risks of false negative testing results. The current risk of transplanting tissue from an HIV infected donor has been reported to be anywhere 1 in 173,000 to 1 in 1 million [6]. Hepatitis B and C are much more prevalant than HIV in the US population. Many patients do not know they are hepatitis C carriers and acknowledge no risk history associated with hep C. The risk of transplanting hepatitis infected tissue is unknown but is probably higher than HIV.

There is also concern about transmission of emerging diseases. There is little data and no screening tests available for newer diseases including West Nile virus and SARS. No tests are available for prion diseases as well.

Uncertainty of Source Material with Allografts

In 2009 a man was found guilty of falsifying blood tests and information about tissue that he sold to tissue banks. From 2005 to 2006 he operated a company called Donor Referral Services. He lied about the donors ages, causes of death, medical histories and whether or not they had a communicable disease. He paid funeral parlors to allow him to harvest tissue in unsterile conditions from donors who had not agreed to donate tissue.

A second case also from 2006 concerns a different company that harvested tissue from donors without permission.

Although no traceable disease transmission was found from either of these cases, they obviously poise a great risk of disease transmission. Although these companies were closed down and prosecuted, the fact that donor tissue is in demand is likely to tempt others into committing fraud to increase their profits.

Recovery Time Is Slower For Allografts Than For Autografts

Some have erroneously stated that recovery is faster with allografts than autografts. Actually studies have shown that while allografts strength is similar to autografts, graft incorporation and remodeling are slower in allografts and that may make them more vulnerable to failure [6]. Scheffler et al [7] examined the differences between allografts and autografts in a sheep model. They found that significantly lower stability and mechanical function in allografts even out to 52 weeks. Revascularization and recellularization were significantly delayed and at 52 weeks still showed incomplete remodeling. Additionally, they found that sterilization with peracetic acid inhibited remodeling in allografts even further [8]. This suggests that sterilization attempts to reduce disease transmission may adversely affect allografts.

In at least some cases the repair process is never fully completed in allografts. Late failure rates appear to be much higher in allografts than in autografts. Below is the video of a patient who had an allograft ACL reconstruction done in 2003. He was seen by Dr Prodromos in early 2009 for a new knee problem. When Dr Prodromos performed arthroscopic surgery, he had a chance to view the repaired ACL. The allograft had partially ruptured and showed obvious lack of remodeling. Ruptured portions of the graft are seen as a lump at the bottom of the graft. Separate strands of the graft are easily seen. Lack of ingrowth can be seen at the point the graft enters the tunnels on either side. Although six years had passed, this allograft had not remodeled significantly.

Experience At Illinois Sportsmedicine

Dr Prodromos has never had an acute failure of an ACL hamstring autograft, which is the only graft he routinely use. However he has revised a number of failed ACL reconstructions from elsewhere, many of them allografts.

One allograft case was particularly worrisome. This was the case of a teenage boy who had an allograft ACL reconstruction done elsewhere, which become infected and failed. He was treated with graft removal and antibiotics and after recovering had a new graft put in. This new graft was from a different tissue bank by a different surgeon at a different hospital. However this graft also became infected and had to be removed. Testing showed it to be different bacteria. As a result of all these problems, both his medial and lateral menisci were removed. He was then referred to our office. Dr Prodromos first had to bone graft his bone tunnels. Then as a second stage he performed a hamstring ACL reconstruction which has worked well. Additionally, he required meniscal transplantation as well to replaced the damaged and removed menisci. Now several years post surgery, the patient is doing well.

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