Summary

This study assessed 50 patients one year post-ACL reconstruction, finding that PCL angle correlates with anterior tibia translation. At the same time, no significant correlations were observed between MRI measurements and patient-reported outcomes.

Abstract

Purpose

Evaluation of the correlations between selected angular and linear MRI measurements with patients clinical outcomes one year after ACL reconstruction.

Methods

A prospective evaluation was executed on 50 patients (24.2±6.4 yrs, general population), who underwent primary single-bundle ACL reconstruction using autogenous hamstring tendon graft with no additional procedures. MRI images were obtained with a 1.5T scanner using a T2-weighted turbo spin echo sequence in the sagittal and coronal oblique plane. Variables subjected to measurement were: PCL angle (PCLA), ACL graft–joint line angle in the oblique plane (ACLGO), ACL graft–joint line angle in the sagittal plane (ACLGS), and anterior tibia translation (ATTMRI). For clinical assessment, the following variables were measured: total range of motion for operated extremity (ROM), knee stability tests: Lachman (LT) and pivot shift (PST); anterior tibia translation measured with the electromechanical arthrometer (ATTOP – operated extremity; ATTD – difference between extremities) and the Lysholm scale was used for assessing patient-reported functional outcomes. The evaluation was taken 12 months (12.4±0.49) after ACL reconstruction. One researcher, experienced in musculoskeletal radiology, was responsible for MRI measurements and one researcher, experienced in diagnosing and treating musculoskeletal disorders, was responsible for clinical evaluation. All correlations were calculated using the rSpearman test and the Alpha level was set at 0.05.

Results

With some exceptions moderate, negative and significant correlations (p<0.05) were found between PCL angle and: LT (r=-0.54), PST (r=-0.38), ATTOP (r=-0.46), ATTD (r=-0.55). A weak positive and significant correlation was found between ACLGO, LT (r=0.37), and ROM (r=0.38). ATTMRI was significantly correlated with LT (r=0.49) and ATTOP (r=0.36). Patient subjective questionnaire Lysholm scale and ACLGS showed no significant correlations with other variables.

Conclusion

We've found evidence to support the hypothesis that radiographic measurements can predict clinical status in patients after ACL reconstruction. The PCL angle value is the most valuable variable that can predict anterior knee instability determined by clinical maneuvers like Lachman or pivot shift tests. A lower PCL angle value correlates with the magnitude of anterior tibia translation in the operated extremity and with increased side-to-side differences. Patient-reported outcomes measured by the Lyscholm scale show no correlations with selected angular or linear measurements.