Traumatic Onset of Medial Meniscus Posterior Root Tears Is Associated With Younger Age While Insidious Onset Is Associated With Chronic Overload and Bone Bruising

Purpose: To evaluate clinical and radiographic findings for medial meniscus posterior root tears (MMPRTs) and investigate their associations with traumatic and insidious etiologies. Methods: Patients who underwent arthroscopic isolated MMPRT repair by one fellowship-trained surgeon from 2019 to 2023 were retrospectively identified. Clinical variables included history of present illness (HPI), medical history, and physical examination findings. Radiographic variables included Kellgren-Lawrence grade, bone bruise, ghost sign, truncation sign, linear hyperintensity perpendicular to the meniscus, meniscal extrusion, tibial slope, and mechanical axis. Patients were stratified by inciting event versus insidious onset for subgroup analysis. Conclusions: Patients with MMPRT associated with an inciting event are typically younger and more likely to present acutely, with a positive McMurray's test. Conversely, patients with insidious presentation are older, present chronically, and exhibit higher rates of bone bruising, particularly when there is varus malalignment. Level of Evidence: Level IV, prognostic case series.