The relationship between graft intensity on MRI and tibial tunnel placement in anatomical double-bundle ACL reconstruction.

Abstract

To determine whether the graft signal intensity of the anteromedial bundle (AMB) on MRI was related to the tibial tunnel placement, anterior-posterior (A-P) stability, and/or cyclops lesion formation following double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. Between January 2010 and August 2016, 65 patients underwent arthroscopic DB-ACL reconstruction and were followed up for a minimum of 2years. Follow-up included 1-week postoperative CT evaluation, 1-year postoperative MRI evaluation, and 2-year postoperative measurement of A-P instability using a KT-2000 arthrometer. Tibial tunnel placement and the location of Parson's knob were expressed as percentages. Patients were divided into two groups according to the graft signal intensity of the AMB on MRI: the high group (grades 2, 3; group H) and the low group (grade 1; group L). There were 23 knees in group H and 42 knees in group L. There was no difference between the two groups regarding the position of Parson's knob. The AMB placement in the tibial tunnel in group H was more anterior than that in group L. The incidence of a cyclops lesion was significantly greater in group H [13 cases (56.5%)] compared with group L [7 cases (16.7%); P = .05]. The arthrometric side-to-side difference was significantly greater in group H (1.67mm) than in group L (0.90mm; P = .019). Group H had a more anterior tunnel location and significantly greater incidence of cyclops lesions than group L. An increased signal intensity of the AMB on MRI indicates A-P instability. Level III retrospective cohort study.