Magnetic resonance imaging and knee stability following ACL reconstruction

This study was undertaken to determine whether there is a correlation between magnetic resonance imaging (MRI) and clinical success after reconstruction of the anterior cruciate ligament (ACL). In a prospective study, 28 patients underwent clinical and MRI examination 3 to 5 years after ACL reconstruction with either the semitendinosus tendon (n = 15) or patellar ligament (n = 13). Knee stability was assessed both clinically and by KT-1000 arthrometer testing. Magnetic resonance imaging was performed with a 0.2-T dedicated system (Artoscan, Esaote, Italy) including sagittal and oblique coronal T1 and T2-weighted images. Magnetic resonance images were evaluated by two readers with regard to signal intensity and continuity of the ACL reconstruction and presence or absence of posterior cruciate ligament buckling. Knee stability and MRI evaluation were each summarized in a 6-point score. Statistical correlation was checked with the Spearman ranked correlation for testing non-normal distributed samples. Statistical testing of all patients' results together showed a significant correlation with a prediction value of 12%, indicating no significant correlation between clinical results and MRI evaluation. Separate statistical testing of the patellar ligament and semitendinosus patients' results showed no significant correlation in either group at all. Thus, no correlation between clinical stability and MRI could be established. Magnetic resonance images after ACL reconstruction using the techniques mentioned above should be interpreted with caution, as they may not relate to the clinical function of the ligament.