New research from Queensland shows that kangaroos are useful alternative animal models for studying human shoulder cartilage biomechanics.

The research team from the Queensland University of Technology in Brisbane studied kangaroo cartilage as an analogue for human tissue, and found that a network of collagen protein close to the surface played an important role in helping the cartilage absorb force without causing damage.

This behaviour was different than that in most studies of knee cartilage, suggesting that artificial knee and shoulder joints may need to be engineered differently, they reported in Applied Physics Letters.

“Knee cartilage has been studied extensively. However, there are only limited studies specifically focusing on shoulder cartilage tissues. We think [studying shoulder cartilage] is important, because, especially in sports activities, there is a possibility that the shoulder may get affected by injuries and eventual osteoarthritic development,” said lead author Yuantong Gu.

The researchers’ findings highlight that shoulder and knee cartilage could differ significantly in their response to external loadings.

They also emphasise the need to engineer an artificial cartilage material to a specific shoulder or knee joint in such a way that it is customized to mimic the different local mechanical environment that the tissue is subjected to within a particular joint, Gu said.

The kangaroo is a suitable alternative animal model for the study of human shoulder cartilage biomechanics because it  has a bidpedal posture, is similar in size to a human and its grabbing, punching and lifting limb action resembles human shoulder-mediated movements, the researchers said.