 ACL injuries are common among athletes of all types. Often they're associated with ramp lesions, injuries to the medial meniscus which cushions the femur and provides stability to the knee joint. Unfortunately, ramp lesions often go undiagnosed, and the most appropriate course of treatment is the subject of much debate. To bridge this gap, researchers examined the prevalence and characteristics of ramp lesions in patients undergoing ACL reconstruction. Their findings are reported in the American Journal of Sports Medicine. The team retrospectively evaluated all patients who underwent ACL reconstruction at a hospital in Lyon, France between November 2015 and November 2018. They used a combination of imaging and surgical techniques to identify whether ramp lesions were present. When they were, the lesions were categorized into five different subtypes, meniscocapsular lesions, partial superior lesions, partial inferior or hidden lesions, complete tears in the red zone, the part of the meniscus with a blood supply, or complete double tears. Patients demographic and clinical characteristics were then evaluated to determine whether they were correlated with a particular lesion subtype. During the 2156 patients evaluated, 334 ramp lesions were observed, resulting in a prevalence of 15.5%. By far the most common ramp lesion subtype was a complete tear in the meniscocapsular junction, representing almost 50% of all observed injuries. The least common was a partial tear in the superior portion of the red zone. Of the five subtypes, partial tears to the inferior side of the red zone were found to be the most likely to be missed in preoperative MRI scans because of their relatively small size and location on the underside of the meniscus. Furthermore, complete rather than partial ramp tears were significantly associated with gross pivot shift or the overall anterolateral stability of the knee. Some lesions may have been missed in this analysis because patients with non-operated ACL injuries, especially those with a partial ACL tear, were not included in this study and the available data for some characteristics and lesion subtypes were low. Nonetheless, the study findings provide important information about the characteristics of ramp lesion subtypes and associated patient characteristics, providing researchers and clinicians further insight into this type of injury and the development of effective treatment strategies.