Researchers at the Oregon Health & Science University said their study of a strain of mice called MRL/MpJ that has such ability might lead to significant improvements of treatments, such as for Tiger Woods' damaged knee cartilage, as well as human shoulder and hip injuries.

"Human cartilage injuries heal poorly and can lead to cartilage degeneration and osteoarthritis," said Assistant Professor Jamie Fitzgerald. "This is an enormous clinical problem. It is estimated that one-quarter of the adult population will have some kind of arthritis by 2020."

Fitzgerald, Cathleen Rich and Dr. Andrea Herzka studied knee injuries in 150 mice. Three months after the cartilage in their knees was damaged, male MRL mice had replaced a significant amount of the injured tissue with healthy cartilage.

"If we can identify what genes or proteins are necessary for cartilage to heal, we can work toward finding similar genes and proteins in humans," Herzka said. An actual treatment, however, "is many years away."

The study's results were reported in a recent issue of the journal Osteoarthritis and Cartilage.