When acl surgery failed?

Acl failure: Acl graft can fail for many reasons. Usually it's a repeat injury. Other reasons can be discussed with an orthopedic surgeon.

Complex topic: Traumatic re-rupture is most common cause of acl graft failure. Failed surgical result can be due to: non-anatomic position of the graft or residual laxity-both can predispose to tear of meniscus+cartilage damage-or to associated injury that was missed in 1st surgery; stiffness; infection, poor rehab, other causes. See an ortho sports medicine specialist, consider getting 2nd opinion. Good luck!