ACL Reconstruction: Second Graft Not Necessary
Tracey Romero • Fri, April 28th, 2017
Patients undergoing anterior cruciate ligament reconstruction may not need a second graft according to new research published in the April 2017 issue of The American Journal of Sports Medicine.
Frank Noyes, M.D., chairman and medical director of the Cincinnati Sports Medicine and Orthopaedic Center at Mercy Health, who spearheaded the study told OTW, “There have been numerous publications, presentations and debates at national meetings, over the past two to three years, on the potential need at the time of an anterior cruciate ligament (ACL) reconstruction of adding a concurrent lateral extra-articular graft reconstruction such as an anterolateral ligament (ALL) or iliotibial band tenodesis (ITB). Authors have cited in vitro studies that an ACL reconstruction alone may not resist the abnormal pivot shift subluxation, and residual symptoms of giving way may still exist after surgery.”
While some authors cite the need for an ALL or ITB procedure in Grade 3 pivot shift knees where there is an injury to both the ACL and anterolateral ligament structures, Noyes said there are also classical studies which suggest that the anterolateral ligament structures are secondary restraints and do not function to resist the pivot shift subluxation.
Looking for further clarification on this debate, Noyes and colleagues conducted the first in vitro study using robotic technology to perform a pivot shift subluxation that involved a 4 DOF (degrees of freedom) loading that best simulates the gross anterior subluxation of both the medial and lateral tibiofemoral compartments in order to examine the effects of a combined ACL and ALL reconstruction.
“The 4 DOF involves the robot loading of anterior tibia loading, internal tibia rotation torque, valgus torque and knee extension-flexion to produce the maximum anterior tibia subluxation of both the medial and lateral tibiofemoral compartments,” Noyes said.
“Prior studies of this type used only a 3 DOF loading (internal tibia rotation, valgus and extension) and did not use the addition of an anterior tibia loading. The internal tibia loading in these 3 DOF studies, in the absence of an anterior tibia load, actually reduces the medial tibiofemoral compartment and reduces the amount of central tibia translation to only a few millimeters.”
In their in vitro study, Noyes and colleagues found that the ALL reconstruction had no effect in limiting tibiofemoral compartment translations in the pivot shift test and produced only modest decrease in ACL graft forces, calling into question the need for ALL reconstruction to correct pivot-shift abnormalities.
“An extra articular reconstruction that did function to limit the pivot shift would do so by over constraining internal tibia rotation which is to be avoided,” Noyes said.
He added, “Our results apply to the use of a BPTB [bone-patellar tendon-bone] graft and not to other ACL grafts that may not be as robust in terms of initial fixation strength. I reserve an extra articular procedure for very select revision knees with prior failures, and that are grossly unstable with involvement of secondary ligament restraints. The recommendation that this added surgery is necessary is not supported by our study conclusions.”