2023 ISAKOS Biennial Congress ePoster
Posterior Displacement Of The Detached Meniscocapsular Ligament Of Ramp Lesion In ACL Injured Knee Observed On MRI In Flexed Knee Position Is Associated With Greater Preoperative Anterior Knee Laxity
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
Japan Community Health care Organization Gunma Central Hospital, Maebashi, Gunma, JAPAN
FDA Status Cleared
Summary
The ramp lesion gap on MRI 120º flexed knee position was associated with joint effusion and greater anterior knee laxity, but not the size of the lesion.
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Abstract
Purpose
To confirm whether posterior displacement of the detached meniscocapsular structure in the ramp lesion could be observed on magnetic resonance images (MRI) in the flexed knee position and to investigate whether posterior displacement of the meniscocapsular structure on MRI in flexed knee position is associated with preoperative greater anterior knee laxity.
Methods
Forty anterior cruciate ligament (ACL) injury patients for whom an attendant ramp lesion was observed on preoperative MRI were included in this study. All subjects received 3-T MRI at 120º of knee flexion before surgery. The gap distance of the ramp lesion on sagittal slices was measured, and a distance greater than 1 mm was classified as gap positive. Also, the presence of effusion pooled in the posteromedial recess was evaluated. Before surgery the side-to-side difference (SSD) in anterior tibial translation (ATT) on stress radiographs at 20º of knee flexion was measured to evaluate anterior knee laxity. During ACL reconstruction, a ramp lesion was found in all knees on a trans-notch view. The length of the ramp lesion was measured using a scale from the posteromedial portal.
Results
Nineteen of 40 knees had ramp lesion gaps greater than 1 mm on MRI at 120º of knee flexion. The mean ramp lesion gap distance was 3.3 ± 2.0 (range, 1.0 to 7.1) mm. There was no significant difference in the size of ramp lesion between gap-positive and gap-negative group (15.2 ± 4.8 mm vs 13.2 ± 4.4 mm; p<0.17). SSD in ATT on stress radiographs in the gap-positive group was significantly greater than that in the gap-negative group (8.7 ± 4.2 mm vs. 6.0 ± 4.0 mm; p<0.05). Fourteen of 19 in gap-positive group had posterior joint effusion on 120º flexed MRI, and none of 21 in gap-negative group had joint effusion. Gap-positive group had significantly higher number of joint effusion than gap-negative group (p<0.01).
Conclusions
The ramp lesion gap on MRI 120º flexed knee position was associated with joint effusion and greater anterior knee laxity, but not the size of the lesion. The necessity for suture repair of ramp lesions should be judged by the instability of the meniscocapsular ligament in the ramp lesion to avoid residual knee instability.