This article describes an anterolateral reconstruction procedure that, when
used in combination with an intra-articular anterior cruciate ligament (AC
L) reconstruction, restores rotary and anterior knee stability. We believe
that failing to recognize lateral instabilities and to perform an extra-art
icular reconstruction is an under-recognized cause of failure of ACL recons
truction. We also describe the indications, medical histories, and physical
examination tests used to determine when an anterolateral reconstruction i
s needed. One should suspect a compromise of the lateral structures when pr
esented with a failed ACL reconstruction in which the tunnels, the graft, a
nd the rehabilitation all seem to have been done properly, or when a prior
lateral procedure has been attempted and failed. In our experience, if a se
cond ACL reconstruction is undertaken without the benefit of a lateral reco
nstruction, it may fail as well.