Serial Changes in Graft Diameter Following Anterior Cruciate Ligament Reconstruction Using Allograft

BackgroundTo evaluate the serial changes in graft diameter during the 2 years following anterior cruciate ligament (ACL) reconstruction using serial magnetic resonance imaging (MRI).MethodsThis study involved 38 patients (38 knees) who underwent arthroscopic ACL reconstruction and had MRI immediately after surgery, at 1 year, and at 2 years. Graft diameter was measured at the distal, middle, and proximal levels of the intra-articular length, selecting the sagittal MRI slice that optimally showed the graft at each level. Correlation analysis was performed to identify the relationship between the difference of each graft diameter and demographic data and postoperative assessment results.ResultsPost hoc analysis over time showed substantial thickening from the immediate postoperative to the 1-year scan (distal, +3.098 mm; middle, +3.284 mm; proximal, +3.074 mm; all P < 0.001), a modest but significant reduction from 1 to 2 years (distal, -0.749 mm; middle, -0.699 mm; proximal, -0.574 mm; all P < 0.001), and persistent enlargement at 2 years compared with those at baseline (distal, +2.348 mm; middle, +2.586 mm; proximal, +2.499 mm; all P < 0.001). Regarding the correlation analyses, the graft diameter measurements at the proximal, middle, and distal sites across the 3 different time points were not significantly correlated with the postoperative results.ConclusionThe graft diameter demonstrated a unimodal peak at 1 year postoperatively, followed by a gradual decrease until 2 years; however, it remained thicker at 2 years than immediately after surgery. These changes were not correlated with postoperative patients' reported outcomes and stability.