"In our study, female athletes after ACLR demonstrated more than four times greater rate of injury within 24 months than their healthy counterparts. This data highlights the fact that ACLR patients who return to playing sports are at greater risk for injury and should take appropriate precautions to prevent injury," said lead author, Mark V. Paterno, PhD, PT, SCS, ATC from the Cincinnati Children's Hospital.

Researchers analyzed data from 78 subjects (59 female, 19 male) between 10 and 25 years old, who underwent ACLR and were ready to return to a pivoting/cutting sport (RTS) and 47 healthy, control individuals. Each subject was followed for injury and athletic exposure for a 24-month period after returning to play. Twenty-three of the ACLR individuals and 4 control subjects suffered an ACL injury. Within the ACLR group, there also appeared to be a trend for female subjects to be two times more likely to suffer an injury on the opposite knee than on the previously injured one. Overall, 29.5% of athletes suffered a second ACL injury within 24 months of returning to activity with 20.5% sustaining an opposite leg injury and 9.0% incurring graft re-tear injury on the same leg. A higher proportion of females (23.7%) suffered an opposite leg injury compared to males (10.5%).

"Our study represents the first report of subsequent ACL injury incidence rate focused on 2 -year outcomes of young, active patients returning to sport. Even though additional research still needs to be performed to support our findings, our data does provide early evidence for re-examining current rehabilitation and return to sport protocols following ACLR," said Paterno.