MR imaging of the posterior cruciate ligament graft: initial experience in 15 patients with clinical correlation

To describe the magnetic resonance (MR) appearance of the posterior cruciate ligament (PCL) graft in the 1st postoperative year and to correlate the MR findings with clinical examination findings.

Nineteen MR examinations were performed in 15 patients (with 15 grafts) 1-33 months after PCL reconstruction. Results of clinical follow-up were available in 14 patients. Graft shape and thickness were recorded, and intrasubstance signal intensity at T2-weighted imaging was graded. The MR findings were correlated with the time between surgery and clinical examination.

At MR imaging, 13 grafts appeared intact, one could not be assessed owing to hardware artifact, and one initially appeared disrupted. Graft thickness was 7-19 mm. There was no significant difference between graft thickness versus time since surgery and signal intensity versus time since surgery (P =.14). In two of three patients who underwent sequential MR examinations, graft thickness and intrasubstance signal intensity decreased as the time between reconstruction and MR imaging increased. Two of 14 patients who underwent physical examination had a posterior drawer, and one also had an anterior cruciate ligament graft tear. Both patients with knee instability demonstrated intact PCL graft fibers at MR imaging. There was no correlation between knee stability and graft thickness, signal intensity, or shape.

After PCL reconstruction, MR imaging in the 1st year depicts a thickened graft with increased signal intensity. There does not appear to be a relationship between clinical stability and findings at MR imaging.