Inclusion Criteria:  18-35 years old Patients who have isolated ACL injury and receive ACL reconstruction surgery at Peking University Third Hospital. With isolated ACL injury (an ACL injury with no need for surgical repairs to other knee structures). All participants have no known disorders or diseases other than ACL rupture.  Exclusion Criteria:  Female patients who are pregnant, or suspected pregnant, or in breastfeeding will be excluded from this study.