Fig. 1.

A graph shows the level of sport/activity participation before primary ACL reconstruction and at latest followup after revision ACL reconstruction. IKDC definitions of sport/activity levels are as follows: Level 0 = unable to perform activities due to knee pain, swelling, or instability; Level 1 = light activities such walking, housework, or yard work; Level 2 = moderate activities such as moderate physical work, running, or jogging; Level 3 = strenuous activities such as heavy physical work, skiing, or tennis; and Level 4 = very strenuous activities such as jumping or pivoting as in basketball or soccer