"Rasenberg et al. proposed the following classification in 1995 3:"
"There is no consensus MRI grading system for MCL injuries, with various systems in current use (c. 2025), which show moderate-to-strong correlation with clinical grading 2. When a discrepancy occurs, MRI is likely to "over-grade" MCL injuries 1,2."
"grade I (low-grade sprain): high signal superficial to the ligament; ligament itself looks normal"
"grade II (high-grade sprain/partial tear): high signal superficial to the ligament; ligamentous high signal or disruption"