Lindsey Vonn’s bid to race downhill at the Milano Cortina Olympics days after rupturing her anterior cruciate ligament (ACL) would be extraordinary but not impossible, according to a U.S. musculoskeletal scientist who said elite conditioning and external knee support could allow her to compete.

Douglas Van Citters, a scientist and ​expert on artificial joints at Dartmouth College in New Hampshire, said athletes were capable of functioning without ‍an ACL ⁠if surrounding structures are strong enough to stabilize the knee.

“There are some individuals who ‍are capable of using their knee in the absence of the ACL,” Van Citters said in an interview on Tuesday, adding that Vonn’s ability to attempt a return so quickly was truly remarkable.