Arthroscopic Double-Bundle Posterior Cruciate Ligament (PCL) Reconstruction: characterization of imaging findings and temporal changes on postoperative MRI.

Abstract

The study aims to characterize the postoperative MRI appearance of double-bundle PCL graft reconstructions (DB-PCL-R) with correlation to clinical PCL stability. A retrospective evaluation of 23 patients, 37 MRIs (12/37, 0-3 months; 8/37, 3-12 months; 17/37, > 12 months) following DB-PCL-R for MRI findings, integrity of the anterolateral (ALB) and posteromedial (PMB) bundles, position of tunnels, peritunnel marrow edema, graft fixation, graft signal, graft-bundle thickening, and synovitis or arthrofibrosis was performed. MRI findings were categorized by time interval postoperatively. PCL stability was assessed clinically (grade 0-III) in all patients. Chi-square or Fisher's exact analysis was performed to explore associations between MRI findings and PCL stability. Graft bundles appeared intact in all cases. PMB graft femoral tunnel was inferiorly positioned in 2/23 patients. The tibial tunnel was inferiorly positioned in 5/23 and superiorly positioned in 2/23 patients. Displaced/fractured fixation hardware related to the PMB tunnel was observed in 3/23 patients, and in the tibial tunnel in 2/23 patients. The highest prevalence of peritunnel marrow edema (50-81.8%) was observed 0-3 months postoperatively, which decreased progressively with increasing timeframe postoperatively. The highest prevalence of increased graft signal (25-62.5%) and graft thickening (25-37.5%) was seen 3-12 months postoperatively, with subsequent decrease on exams > 12 months postoperatively. Synovitis or arthrofibrosis was observed in 87.5% of exams obtained 3-12 months postoperatively, with a decrease (58.8%) on MRI exams > 12 months post-surgery. No significant correlation was observed between MRI variables and PCL stability (p-values, 0.085-0.815). Although a high prevalence of peritunnel edema, increased graft signal and thickness and synovitis/arthrofibrosis may be encountered early postoperatively, particularly in the first 12 months; these findings are not correlated to PCL instability and seem to decrease over longer-term follow-up.