the effect of anterior cruciate ligament reconstruction technique on graft signal intensity at mid-term follow-up

Background: anterior cruciate ligament reconstruction (acl-r) technique affects graft positioning. however, how acl graft positioning affects graft signal intensity (gsi) is yet unknown. the aim of our study was to find out if acl-r technique affects gsi at mid-term follow-up. patients and methods: a total of 50 patients were included in the study. they underwent 3.0 t mri of the knee 4-7 years after acl-r. patients were divided into two groups according to acl-r technique (transtibial technique with rigidfix fixation [group 1] and anteromedial portal technique with endobutton fixation [group 2]). gsi, graft failure, graft impingement and graft position were assessed. gsi characteristics were evaluated on proton density turbo spin echo fat saturation images. graft was divided into two portions – intraarticular portion (iap) and intraosseous portion (iop). intraosseous portion was further divided into two parts – femoral (fiop) and tibial (tiop). results: graft failure was identified in 12.0%. only 9.8% showed low signal intensity of the entire graft course. group 2 showed higher rates of increased graft signal intensity (igsi) of the iap and fiop. patients with igsi of the iap showed more horizontal position of the coronal tibial tunnel. patients with igsi of the fiop showed more horizontal position of the coronal femoral tunnel. patients with igsi of the tiop showed more horizontal position of the sagittal tibial tunnel. conclusion: igsi can be seen in the majority of patients after acl-r at mid-term follow-up. our study demonstrates that graft tunnel positioning and graft fixation device may influence gsi.