FOR MORE THAN TWO DECADES, orthopaedic specialists have used donor tissue to repair damaged or deficient cartilage in the knees, shoulders, ankles and other moving parts of patients considered too young for joint-replacement surgeries. The procedure, a form of osteochondral allograft transplantation, involves grafting healthy bone and cartilage from organ donors into damaged joints. When successful, it can give new life to people suffering the pain and restricted mobility of traumatic injuries and degenerative-joint conditions. So far, thousands have benefitted. Now, thanks to a breakthrough discovery by an MU-led research team, even more may do so.
As an “immunoprivileged” tissue, donated bone-cartilage grafts do not need to be matched to the prospective recipient in terms of blood or tissue typing. Nor are anti-rejection drugs required. The grafts do, however, need to be carefully matched in terms of patients’ size and shape, then tested to ensure the tissue is disease free. This takes time. Sometimes too much time. Current storage techniques can maintain the cartilage at high quality levels of viability for 28 days at most.
“Nearly 80 percent of all donated tissue has to be discarded because the tissue banks cannot find an appropriate match with a patient who needs a transplant after the graft is cleared, but before it goes bad,” says Jimi Cook, leader of the MU team.
Cook, veterinary researcher and professor of orthopaedic surgery at MU, along with Aaron Stoker of MU’s Comparative Orthopaedic Laboratory, Clark Hung and Eric Lima from Columbia University, and MU orthopaedic surgery professor James Stannard, has developed a system to extend cartilage’s relatively short shelf life, one that will significantly widen the tissue-transfer window.
The system involves using a specially-designed container and storage solution to maintain transplant-quality tissue. Testing results, detailed in an upcoming edition of the Journal of Knee Surgery, showed the new system preserved tissue for more than twice the current four-week limit, extending cartilage’s usable life to as much as 63 days. The team also developed a way to monitor the quality of the stored tissue simply by testing a few drops of their patented storage solution.
“Not only have we been able to increase maximum tissue storage time from 28 to 63 days, but tissue stored for 63 days using our new method is of much higher quality than tissue on its 28th day,” Cook says. “This is important because the quality of the tissue at the time of a transplant procedure markedly affects long-term success for the patient.”
Cook says the new MU storage system is currently under licensing negotiation for clinical application. He hopes grafts stored using the new system will be available at the Missouri Orthopaedic Institute and similar facilities within the year.