Incidence and Detection of Meniscal Ramp Lesions on Magnetic Resonance Imaging in Patients With Anterior Cruciate Ligament Reconstruction.

BACKGROUND: Meniscal ramp lesions have been reported to be present in 9% to 17% of patients undergoing anterior cruciate ligament (ACL) reconstruction. Detection at the time of arthroscopy can be accomplished based on clinical suspicion and careful evaluation. Preoperative assessment via magnetic resonance imaging (MRI) has been reported to have a low sensitivity in identifying meniscal ramp lesions.

PURPOSE: To investigate the incidence of meniscal ramp lesions in patients with ACL tears and the sensitivity of preoperative MRI for the detection of ramp lesions.

STUDY DESIGN: Case series; Level of evidence, 4.

METHODS: All patients who underwent ACL reconstruction by a single surgeon between 2010 and 2016 were included in this study, and patients with medial meniscal ramp lesions found at the time of arthroscopy were identified. The sensitivity of MRI compared with the gold standard of arthroscopic evaluation was determined by review of the preoperative MRI musculoskeletal radiologist report, mimicking the clinical scenario. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI.

RESULTS: In a consecutive series of 301 ACL reconstructions, 50 patients (33 male, 17 female) with a mean age of 29.6 years (range, 14-61 years) were diagnosed with a medial meniscal ramp lesion at arthroscopic evaluation (16.6% incidence). The sensitivity of MRI for ramp lesions was 48% based on the preoperative MRI report. A secondary finding of a posteromedial tibial bone bruise was identified on preoperative MRI in 36 of the 50 patients with ramp lesions in a retrospective MRI review by 2 orthopaedic surgeons.

CONCLUSION: Medial meniscal ramp lesions were present in approximately 17% of 301 patients undergoing ACL reconstruction, and less than one-half were diagnosed on the preoperative MRI. A posteromedial tibial bone bruise was found to be a secondary sign of a ramp lesion in 72% of patients. Increased awareness of this potentially combined injury pattern is necessary, and careful intraoperative evaluation is required to identify all meniscal ramp tears.