Magnetic Resonance Imaging shows low sensitivity but good specificity in detecting ramp lesions in children and adolescents with anterior cruciate ligament injury: a systematic review

Importance: The diagnosis of ramp lesions can be problematic, even with arthroscopy, due to their extreme posteromedial position. Consequently, they have been colloquially referred to as the "hidden lesions" of the knee. Undiagnosed and untreated injuries in this knee region may be associated with ongoing dynamic rotational laxity of the knee after anterior cruciate ligament reconstruction and an increased risk of anterior cruciate ligament graft failure. Aim: This study aimed to systematically review the literature to assess the sensitivity, specificity and accuracy of magnetic resonance imaging (MRI) for detecting ramp lesions in children and adolescents with anterior cruciate ligament (ACL)-deficient knees. It was hypothesized that MRI has poor sensitivity for identifying ramp lesions in children and adolescents. Evidence review: A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The following search terms were used in the title, abstract, and keywords fields: "ramp" or "meniscus" AND "children" or "adolescents." The outcome data extracted from the studies were incidence of ramp in concomitant with ACL lesion, MRI sensitivity, specificity, accuracy and positive and negative predictive values (PPV and NPV). Findings: Of the 387 patients with ACL injury, 90 were reported to have ramp lesions (23.3%). The mean age at the time of diagnosis was 15.3 ± 0.81 years. The mean time from injury to MRI was 116.1 ±113.5 days, while the mean time from injury to surgery was 172.6 ±139.1 days. The MRI taken to detect ramp lesions in the paediatric population showed a pooled sensitivity of 50%, specificity of 75%, accuracy of 70%, PPV of 41%, and NPV of 79%. Conclusions and relevance: The prevalence of ACL-associated ramp lesions in children and adolescents is similar to that in adult populations. Magnetic resonance imaging has low sensitivity but good specificity for assessing ramp lesions. In the presence of a posteromedial tibial bone bruise or a thin fluid signal separating the posterior horn of the medial meniscus and the posteromedial capsule a ramp lesion should always be suspected. Level of evidence: Level IV. Study registration: PROSPERO -: CRD42023453895.