2019 ISAKOS Biennial Congress ePoster #1024
MRI Diagnosis of Medial Meniscal Ramp Lesions in Patients with Anterior Cruciate Ligament Injuries
Kazuhisa Hatayama, MD, PhD, Maebashi, Gunma JAPAN
Masanori Terauchi, MD, Gunma-Ken JAPAN
Hiroshi Higuchi, MD, PhD, Maebashi, Gunma JAPAN
Satoshi Nonaka, MD, Maebashi, Gunma JAPAN
Gunma Central Hopital, Maebashi, Maebashi, JAPAN
FDA Status Cleared
The sensitivity of MRI for diagnosing ramp lesions was significantly lower than that for medial meniscal body tears, and bone contusion of the posterior lip of the medial tibial plateau on MRI was not associated with ramp lesions.
Longitudinal tears of the medial meniscus posterior horn (MMPH) around the meniscocapsular junction are frequently associated with anterior cruciate ligament (ACL) injuries, and termed as “ramp lesions” The purposes of our study were to prospectively evaluate the sensitivity and specificity of MRI for diagnosing ramp lesions, to compare them between 1.5 and 3-T MRI, and to evaluate whether bone contusion of the posterior lip of the medial tibial plateau was associated with ramp lesions.
For 155 knees that underwent primary ACL reconstruction, we prospectively examined for ramp lesions and medial meniscal body tears on MRI. MRI diagnosis of ramp lesions required high signal irregularity of the capsular margin or separation in the meniscocapsular junction of the MMPH on sagittal images. Bone contusion of the posterior lip of the medial tibial plateau was verified in 105 knees with MRI performed within 6 weeks after injury. All ACL reconstructions were performed by a single surgeon who had more than ten years of experience in performing ACL reconstruction. During the surgery, we performed systematic arthroscopic exploration of the MMPH to identify the ramp lesion. First, the presence of a meniscal tear was evaluated through standard anterior viewing using an anterolateral portal. Then, the 30° arthroscope was introduced from anterolateral portal through the intercondylar notch between the posterior cruciate ligament and the medial wall of the intercondylar notch into the posterior recess, and the presence of a ramp lesion was verified. In cases where a ramp lesion was suspected, the probing of the MMPH using a 20G needle or probe from a standard posteromedial portal to the MMPH was done to detect an eventual ramp lesion. The sensitivity and specificity of MRI for ramp lesions and body tears were measured. Furthermore, we evaluated whether bone contusion of the medial tibial plateau was associated with ramp lesions. The chi-square test was used to compare the sensitivity and specificity on MRI between ramp lesions and body tears, and the incidence of bone contusions of medial tibial plateau among patients with ramp lesions, body tears, and no medial meniscal tear. A P-value of < .05 was considered significant.
During surgery, ramp lesions were observed in 46 knees and medial meniscal body tears were seen in 35 knees. The sensitivity of MRI for ramp lesions was 71.7% and specificity was 90.5%. The sensitivity for ramp lesions was significantly lower than that for meniscal body tears (94.3%) (P=0.01). The sensitivity of 3-T MRI (83.3%) was superior to that of 1.5-T MRI (67.6%), but not significantly different. The incidence of bone contusions was not significantly different among ramp lesions (38.5%), body tears (40.0%), or no tears (30.5%).
The sensitivity of MRI for diagnosing ramp lesions was significantly lower than that for medial meniscal body tears. Bone contusion of the posterior lip of the medial tibial plateau on MRI was not associated with ramp lesions. Even if ramp lesions are not identified on MRI, the transcondylar observation should be routinely performed during surgery so as not to miss lesions.