2025 ISAKOS Biennial Congress ePoster
Magnetic Resonance Imaging at 120° Flexed-Knee Position is a Novel Method for Preoperative Detection of Meniscal Ramp Lesion in Anterior Cruciate Ligament-Injured Knee
Satoshi Nonaka, MD, Maebashi, Gunma JAPAN
Kazuhisa Hatayama, MD, PhD, Maebashi, Gunma JAPAN
Hibiki Kakiage, MD, Maebashi, --お選びください-- JAPAN
Masanori Terauchi, MD, Gunma-Ken JAPAN
HIrotaka Chikuda, MD, PhD, Maebashi, Gunma JAPAN
JCHO Gunma Central Hospital, Maebashi, Gunma, JAPAN
FDA Status Not Applicable
Summary
We compared the diagnostic performance of MRI at knee flexion and near the knee extension position for detecting meniscal ramp lesion. MRI at 120° knee flexion was more useful for detecting meniscal ramp lesion than conventional MRI at near the knee extension.
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Abstract
Background
Detection of meniscal ramp lesions concomitant with anterior cruciate ligament (ACL) injury using conventional magnetic resonance imaging (MRI) has low sensitivity and these lesions are currently difficult to diagnose preoperatively.
Purpose
To assess the accuracy of MRI in detecting the presence of meniscal ramp lesion at 120° flexed-knee position and to compare with that in near extended-knee position. The hypothesis was that the diagnostic performance of MRI in 120º flexed-knee position would be better than that in extended-knee position.
Methods
This retrospective study of prospectively collected data between August 2018 and January 2024 included 154 consecutive patients with ACL injuries. All patients underwent 3-T MRI in near extended- and 120º flexed-knee positions preoperatively. The presence of ramp lesions were separately detected on each MRI scan and confirmed by arthroscopy during ACL reconstruction. Diagnostic sensitivity, specificity, intra- and inter-observer agreement, and conditional relative odds ratios (ORs) were calculated to compare the accuracy of the two MRI modalities. As a sub-group analysis, diagnostic performance in 4 durations from injury to taking MRI (under 30 days, 30-90 days, 90-365 days, over 365 days) were also investigated.
Results
This study included 154 patients (79 men and 75 women; mean age: 29.0 ± 14.2 years). Sixty-two ramp lesions were observed on arthroscopy (40.2%). The sensitivity and specificity of MRI in near extension were 69.4% and 77.2%, respectively, while those in flexion were 91.9% and 94.6%, respectively. The sensitivity and specificity of MRI at knee flexion were significantly better than those at near knee extension (p = 0.001 and p < 0.001, respectively). Intra- and inter-observer agreement was moderate-to-good for MRI in near extension (Cohen’s Kappa coefficient (k) = 0.74/0.58) and very good for MRI in flexion (k = 0.91/0.86). The conditional relative OR between MRI at these two positions was 10.3 (95% confidence interval, 4.8–21.8). The diagnostic sensitivity/specificity under 30 days (n=27) were 72.0/50.0% at knee extension and 100%/100% at knee flexion, 30-90 days (n=66) were 78.5/76.3% and 96.4/92.1%, 90-365 days (n=36) were 70.0/84.0% and 90.0/92.3%, and over 365 days (n=25) were 46.2/100% and 76.6/100%, respectively.
Conclusions
The diagnostic accuracy of MRI in the 120º flexed-knee position for detecting meniscal ramp lesions was superior to that in the near extended-knee position. This advantage was similar regardless of the duration from injury to taking MRI.