Summary

This study compares MRI and CT-based evaluations of femoral bone tunnels in anatomical ACL reconstruction, involving 22 patients. MRI, which avoids radiation exposure, showed comparable accuracy to CT in assessing the AM and PL bundles of the lateral femoral condyle, with no significant differences in measurements, suggesting MRI as a safer alternative for repeated imaging, especially in young pat

Abstract

Introduction

Recent advancements in MRI technology have made detailed bone morphology evaluation possible through a bone-like imaging technique. Since many patients with ACL injuries are teenagers who should avoid radiation exposure, MRI-based bone tunnel evaluation is an attractive alternative. The purpose of this study is to compare bone tunnel evaluations using MRI with traditional CT evaluations.

Methods

We included 22 knees from 22 patients who underwent anatomical ACL reconstruction using the semitendinosus tendon at our institution and were able to undergo both CT and 3.0T MRI scans. FRACTURE was used to obtain CT-like images. The centers of the AM and PL bundles of the lateral femoral condyle were evaluated using the quadrant method from the 3D images and compared with the results obtained from CT. The inter-observer reliability of bone tunnel position in MRI was assessed by three orthopedic specialists using ICC (2.1).

Results

In MRI, the AM bundle had a Depth (D) of 14.5±2.3% and a Height (H) of 22.9±9.6%, while the PL bundle had a D of 23.1±4.1% and an H of 52.1±5.8%. In CT, the AM bundle had a D of 15.8±2.3% and an H of 22.8±9.1%, while the PL bundle had a D of 29.1±9.2% and an H of 53.3±8.2%. There were no significant differences between MRI and CT measurements (p < 0.05). The ICC for MRI was 0.878 (95% CI: 0.696–0.965) for the AM bundle and 0.961 (95% CI: 0.883–0.989) for the PL bundle.

Discussion

The position of the femoral bone tunnel in anatomical ACL reconstruction significantly impacts the function of the reconstructed ligament and clinical outcomes. This study demonstrated that MRI-based bone tunnel evaluation is comparable to traditional CT-based evaluation. Since MRI poses no radiation exposure risk even with repeated imaging, future research should focus on examining changes in bone tunnels before and after range of motion or weight-bearing training.

Conclusion

Femoral bone tunnel evaluation using MRI, which avoids any radiation exposure, was found to be as effective as traditional CT-based evaluation.