Summary

The overall prevalence of meniscal ramp lesions in patients with ACL injuries is high. Contact sports at ACL injury, pivot-shift-type bone bruising, PMT bone bruising and the presence of a Segond fracture on MRI are associated with meniscal ramp lesions.

Abstract

Background

Even though direct arthroscopic visualisation is regarded as the gold standard for diagnosing ramp lesions, several ramp lesions might be missed intraoperatively due to their difficult visualisation through the anterolateral and anteromedial portals. MRI is regarded as the best imaging modality to diagnose meniscal ramp lesions, even though its accuracy has been questioned due to the varying sensitivity reported. It should, however, be noted that studies evaluating MRI accuracy have used different and limited pathological signs to define ramp lesions. In some studies MRI criteria were not even reported. In a recent study, using an extension of Thaunat’s classification, Greif et al. described seven different types of meniscal ramp lesion together with their MRI appearance.

Purpose

To evaluate the prevalence of and factors associated with meniscal ramp lesions on MRI in patients with ACL injuries, using well-defined radiological signs (Greif´s classification).

Methods

Data from a national multicentre longitudinal cohort ACL study were analysed. Only patients who underwent MRI were included in this study. All MRI scans were reviewed by an orthopaedic knee surgeon and a musculoskeletal radiologist. The patients were divided into two groups, those with and without ramp lesions according to MRI findings. Univariable and stepwise forward multiple logistic regression analyses were used to evaluate patient characteristics and concomitant injuries on MRI associated with the presence of meniscal ramp lesions.

Results

A total of 253 patients (52.2% males) with a mean age of 25.4±7.1 years were included. The mean time from ACL injury to MRI was 19.6±15.2 days. MRI examinations were performed using a 1.5 (n=115) or 3.0 (n=138) Tesla scanner. The overall prevalence of meniscal ramp lesions was 39.5% (100/253). The subtype distribution was as follows: 13(13%),type 1(meniscocapsular ligament tear); 4(4%), type 2(partial superior peripheral meniscal horn tear); 7 (7%),type 3A(partial inferior peripheral posterior horn meniscal tear);7(7%),type 3B(meniscotibial ligament tear); 20(20%),type 4A(complete peripheral posterior horn meniscal tear);43(43%),type 4B(complete meniscocapsular junction tear);6(6%),type 5(peripheral- posterior horn meniscal double tear).
Univariate analyses showed that contact sports at ACL injury, pivot-shift-type bone bruising, posteromedial tibial (PMT) bone bruising, lateral femoral condyle impaction and the presence of a Segond fracture increased the odds of having a meniscal ramp lesion. Stepwise forward multiple logistic regression analysis revealed that the presence of a meniscal ramp lesion was associated with contact sports at ACL injury (odds ratio [OR] 2.50;95% confidence intervals [CI]1.32-4.72;P=0.005), pivot-shift-type bone bruising (OR 1.29;95% CI 1.01-1.67;P=0.04), PMT bone bruising (OR 4.62;95% CI 2.61-8.19; P<0.001) and the presence of a Segond fracture (OR 4.38;95% CI 1.40-13.68;P=0.001).

Conclusion

The overall prevalence of meniscal ramp lesions in patients with ACL injuries was high (39.5%). Contact sports at ACL injury, pivot-shift-type bone bruising, PMT bone bruising and the presence of a Segond fracture on MRI were associated with meniscal ramp lesions. Given their high prevalence, meniscal ramp lesions should be systematically searched for on MRI in patients with ACL injuries. Knowledge of the factors associated with meniscal ramp lesions may facilitate their diagnosis, raising surgeons’ and radiologists’ suspicion of these tears.