Primary Anterolateral Ligament Rupture in Patients Requiring Revision Anterior Cruciate Ligament Reconstruction: A Retrospective Case-Control Magnetic Resonance Imaging Review.

Abstract

To compare the initial rate of anterolateral ligament (ALL) injury at the time of anterior cruciate ligament (ACL) rupture in patients who subsequently experienced ACL reconstruction graft failure versus patients who did not experience subsequent ACL reconstruction graft failure. Our institution's electronic medical record database was queried for patients who underwent primary ACL reconstruction with subsequent ACL graft rupture. Exclusion criteria included unavailable MRI scan, chronic ACL injury, multi-ligamentous injury, previous ACL reconstruction, and age younger than 13 or older than 50 years. Each patient was paired with an age-, gender-, and graft-matched control who underwent ACL reconstruction without subsequent graft rupture. Each patient was diagnosed with an intact, partially injured, or fully ruptured ALL on initial MRI. The location of ALL injury was also noted. The incidence and location of ALL rupture were compared using χ² analysis. 1,967 patients underwent primary ACL reconstruction. 128 patients experienced ACL graft rupture, and 55 patients (43%) had MRI scans available for review. 39 of these patients fulfilled inclusion criteria and were matched with a control patient. In the revision group, the ALL was diagnosed as intact, partially torn, and completely torn in 17, 14, and 8 patients, respectively, compared to 18, 13, and 8 patients, respectively in the control group. No difference was found in frequency of ALL rupture (Pearson χ² = 0.066; P = .968) or rupture location (Pearson χ² = 4.00, P = 0.135). The incidence of initial ALL injury as documented on MRI was not different in patients who experienced subsequent ACL graft rupture compared with patients who did not experience ACL graft rupture after primary ACL reconstruction. The ALL was more commonly injured on the tibial side in patients with ACL graft rupture and femoral-sided lesions were more common in control patients. Level III, prognostic case-control study.