Weighing the risks and gains of allografts vs. autografts, surgeons reported allograft knee procedures prove more successful by diminishing pain, cutting costs and improving function and quality of life.
Allograft use is one of the hottest topics [in the United States] right now, said Christopher Harner, MD, of Pittsburgh, U.S.A., in a special symposium on allografts at the 7th European Federation of National Associations of Orthopaedics and Traumatology Congress (EFORT). Harner was joined by fellow orthopaedic surgeons Gary G. Poehling, MD, of Winston-Salem, U.S.A., and René Verdonk, MD, PhD, of Gent, Belgium, a member of the Orthopaedics Today International Editorial Advisory Board.
There has been an explosion in the use of musculoskeletal allografts in sports medicine, and last year more than 1 million graphs were distributed, Harner said. Although the tissues improved in safety in the last 10 to 15 years and disease transmission is rare, it still exists.
Harner said the advantages of allografts include low donor site mobility, decreased operating time and less pain in the first six weeks. He called it the preferred procedure in complex cases such as multiple ligament revision cases. He said the disadvantages include disease transmission and slow incorporation.
Patients in need of surgery
Verdonk stressed the need for using the most efficient surgery possible because patients requiring knee reconstruction present with tremendous pain, are unable to perform work duties and lack a good quality of life as a result their disability.
In the next 10 years, medial meniscus transplantation, together with osteotomy, will be the best course of treatment if you consider the numbers, Verdonk said. The isolated meniscal lateral transplants in our clinics are the best indications in our experience of open surgery. ... We are very happy when there is a meniscal wall where we can fix the meniscus when we do the transplantation.
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Two cases demonstrate reconstruction of extensive skeletal defects with intercalary allografts stabilized with plates and screws. Union was achieved at the osteosynthesis sites.
Courtesy of William F. Enneking
The symposium participants agreed that allografts cost considerably less than autografts in terms of overall treatment expenses.
Everybody talks about the costs, and that has a lot to do with what your situation is with your tissue banks, said Poehling, who chaired the symposium. We did a cost analysis, and we looked at autograft and allografts and our medical expense data showed it was USD 1000 less expensive to do an allograft. And you might ask: How can that be?
We saw that it was a little more expensive for the actual allograft, but at that time our allograft cost was USD 400 average and that was between 1994 and 1999. It is more expensive now, but relatively speaking, it is less than USD 1000 [for an allograft] even now, he said.
Less physical therapy needed
Poehling said the expenses of the recovery room were higher for the patients who received an allograft, but those costs were offset by shorter OR times, lower anesthesia costs and no overnight stays. In addition, patients receiving autografts spent an average of six months in physical therapy following surgery. The allograft group completed their physical therapy in appoximately three months.
Ultimately, it was less expensive to treat the allograft patients. We saw nearly a USD 2000 difference in physical therapy costs between the two groups, he noted.
The three presenters also discussed the risk of disease transmission in allograft tissue, as well as problems with mechanical properties and incorporation difficulties.
Harner said 62 cases of allograft infections were reported to the U.S. Centers for Disease Control and Prevention (CDC) just within the past year.
There were 26 bacterial infections, and remember that this is [only] what was reported. I am sure there are a number of cases that were not reported, he said. Of those 26 cases, 13 came from one tissue bank.
He said the CDC also reported one case of hepatitis B, three cases of hepatitis C and four cases of HIV.
Allografts remarkably safe
An authority on allograft tissue disease transmission, William F. Enneking, MD, told Orthopaedics Today that allografts are, in fact, very safe.
Allografts, in terms of viral transmission particularly HIV and hepatitis C are remarkably safe, with the risk of transmission less than one in 2 million. Bacterial contamination is also very rare due to vastly improved techniques of sterile procurement, rigid donor criteria and strict culture surveillance, said Enneking, the Eugene L. Jewett Professor of Orthopaedic Surgery and Distinguished Service Professor at the University of Florida in Gainesville, U.S.A.
Under new rules, tissue banks handling cellular and tissue-based products (HCT/P) must recover, process, store, label, package and distribute them according to specific procedures and have quality systems that will prevent the introduction, transmission and spread of communicable diseases. The rule also applies to musculoskeletal allografts, according to the U.S. Food and Drug Administration (FDA).
Tissue bank registration
Harner said all tissue banks in the United States must register with the FDA. Currently there are 154 tissue banks registered. Registration began in 1993, he said, and 36 out of the 154 banks have never been inspected.
To monitor these banks in the United States, a voluntary group called the American Association of Tissue Banks (AATB) has served as an accreditation and inspection agency for the industry since 1976. Ninety of 154 tissue banks currently belong to the AATB, and the number has significantly increased over the past few years, Harner said. The AATB offers a three-year certificate, and agencies must be reinspected every three years as part of their certificate renewal program.
Standards reviewed, updated
Likewise, The standards are reviewed and updated [by the FDA] and constantly changed depending on the issues that occur, especially [with] infection, Harner said. The FDA ultimately has the power to shut down tissue banks, and did so in two cases just in the last four years, he added.
To improve sterilization methods, tissue specialists are investigating the safety and effectiveness of new approaches. According to Enneking, secondary sterilization with either ethylene oxide or irradiation causes biologic and biomechanical damage to the tissue so that so-called clean procurement requiring secondary sterilization as opposed to sterile procurement in an operating room environment is seldom done anymore.
However, there are pressures to develop chemical techniques that make tissues even safer without degrading either the biologic or biomechanical quality of the tissue, he said. Therefore, the safety issue must constantly be balanced against efficacy.
Poehling said the availability of allograft tissue constantly fluctuates.
If youre looking for bone tendon allografts, they are in short supply. Soft tissue allografts are certainly more available. Freeze dried allografts have a long shelf life, and they dont require refrigeration or anything like that, he said.
When asked how long fresh allogeneic osteochondral transplants will remain viable for transplantation, Enneking said the sooner the better.
When stored in an appropriate environment, seven to 10 days appears to be the outer limit for a high percentage of the chondrocytes to survive, he told Orthopaedics Today. This is a very narrow window to perform the necessary laboratory and administrative measures to ensure patient safety.
Enneking added there are a plethora of growth factors that are known to promote bone growth and healing. There is also ample evidence that various combinations are better than an individual factor.
Clearly, there are also the critical factors of the timing, presence or absence, and amount of growth factors that remain to be established, he added. We have just begun to scratch the surface of understanding in areas where great progress appears possible.
For more information:
- Poehling G, Harner C, Verdonk R. Symposium: Allografts in sports medicine. Presented at the 7th European Federation of National Associations of Orthopaedics and Traumatology Congress. June 4-7, 2005. Lisbon.