December 11, 2023

Knee reconstruction using kangaroo tissue is one step closer to reality, with human trials due to begin in 2024.

“I’ve always said that the kangaroo is nature’s greatest athlete,” said Dr. Nick Hartnell, an orthopedic surgeon and one of the authors of the study. “They are truly the most impressive animals – they can jump distances of up to 12 meters (39 ft), jump over fences up to 3 meters (10 meters) and travel at speeds of 70 km/h (43 mph) jump.

“Watching them move, I began to wonder to what extent this ability to move was related to the way their tendons formed and whether they could be used to replace broken human ligaments,” he said.

After years of research, Hartnell and his team are now conducting human xenograft trials to repair injuries such as a ruptured anterior cruciate ligament (ACL).

Xenotransplantation, the transplantation of organs or other tissue from another species, has become a feature of surgery, such as replacing a heart valve with a donor pig’s. However, biocompatibility is a huge hurdle. The team believes they have also cracked the code of how to ensure “foreign” kangaroo groups are not ostracized by human recipients.

Dr Hartnell said: “Xenotransplantation – using tendons from other species – has the potential to be a better option, but so far the medical community has struggled to find a suitable donor species that is strong, durable, Tendons that don’t get repelled.”

While the Australian marsupial may not provide humans with superhuman jumping abilities, it does offer a promising alternative to current treatments.

In the United States, approximately 200,000 ACL ruptures occur each year, and as many as a quarter of these require additional surgery. The nature of the injury means that additional tissue will need to be grafted at the injury site. Grafts taken from other parts of a patient’s body often increase pain and recovery time, while grafts from deceased donors and synthetic sources both present additional problems for surgeons.

“These cadaveric tendons are in very limited supply and unfortunately, the strength is often not as good as we would like, resulting in patients with weaker knees,” Dr. Hartnell said.

“Additionally, as many as one in four ACL reconstruction surgeries fail,” he added. “If that happens, or the person injures both ligaments at the same time, or a second time, they don’t have a choice.”

Not only is kangaroo tendon likely to be the best choice, but it can be procured elsewhere (cull, food production) and this part of the animal is used in pet food (if available).

All studies were carried out on kangaroo tendons obtained from other industries, so no live animals were involved.

Dr Hartnell added: “As far as tendons are concerned, they are biologically superior, but at the moment all that potential is wasted because tendons are not being used for anything.”

The research team hopes successful human trials will pave the way for the use of kangaroo tendons in surgery around the world.

The study was published in American Journal of Sports Medicine.

source: Macquarie University