A recent study from the US Naval Academy has shown that the use of NSAIDs (nonsteroidal anti-inflammatory drugs) such as advil, motrin, aleve, diclofenac and meloxicam around the time of surgery or afterward were associated with a higher rate of failure of the graft and a higher rate of second operations being needed to re-reconstruct the ACL. An older study had shown that use of one particular NSAID, ketorolac, resulted in increased looseness of knees after ACL reconstruction.
I avoid the use of these drugs before, and for 18 months after, ACL reconstruction while the ACL graft is maturing for just this reason. These drugs also have a high incidence of severe side effects including GI bleeding which can be fatal, kidney failure, liver failure and more. There are numerous studies showing that NSAIDs interfere with healing of bone, ligament, tendon and similar tissues. However this study shows that this is more than a theoretical risk.