Summary

Anterior spontaneous drawer of the knee on MRI is significantly associated with the presence of medial meniscal lesion in patients with ACL complete rupture.

Abstract

Introduction

The rupture of the anterior cruciate ligament (ACL) leads to an increased anterior tibial translation while the ligament is put under tension. Furthermore, the literature has shown that patients with complete ACL rupture had a anterior spontaneous drawer (ASD) on MRI significantly greater than control. The main objective of the study was to assess the relationship between the ASD on MRI and the anatomical lesions in case of complete rupture of the ACL.

Material And Methods

This retrospective study included patients with complete ACL tear confirmed by arthroscopy in 2010-2015. The exclusion criteria were an association with a posterior cruciate ligament rupture, a femoro-tibial dislocation, a partial ACL rupture, and previous knee surgery. Preoperative MRI were performed in the supine position, knee flexed to 30°. The ASD was measured by axial superposition of the bi-condylar section and the section passing through the tibial plateau (average value of the median drawer and lateral drawer). The presence of associated lesions (yes / no) was assessed (medial and lateral meniscus, medial and lateral cartilage, internal and external lateral ligament, shell and bone edema). The measurements were performed twice by two experienced radiologists at two week intervals. The reproducibility inter- and intra-observer was evaluated by the Pearson coefficient (r) and the intraclass correlation coefficient (?). Factors associated with an ASD> 2mm were investigated by multivariate logistic regression.

Results

91 patients were included, mean age 31.1±10.1 years, 34 women and 57 men. The mean ASD was 4.7 ± 2.3mm and the median was 4mm. On preoperative MRI, 60.4% of patients had bone edema, 48.4% medial meniscal lesion and 36.4% a lateral meniscal tear. The reproducibility inter- and intra-observer measurements of ASD was excellent. The ASD was significantly greater if patients had medial meniscal lesion (5.4±2.3 mm vs 4±2.1 mm, p=0.003). No significant difference was found for the other lesions. 80 (87.9%) patients had ASD> 2mm and the only identified risk factor was the presence of medial meniscal lesions (OR=9.4, 95%CI [1.2 to 77.8], p = 0. 03).

Conclusion

Anterior spontaneous drawer of the knee on MRI is significantly associated with the presence of medial meniscal lesion in patients with ACL complete rupture. A prospective study is ongoing in order to assess the prognostic value of the anterior spontaneous drawer on antero-posterior stability and functional outcomes of the knee after ligament reconstruction.