Clinical versus MRI grading of the medial collateral ligament in acute knee injury

Abstract Sensitivity, specificity, and agreement between clinical and magnetic resonance imaging (MRI) gradings of the medial collateral ligament (MCL) after acute knee injury were evaluated in 362 patients. Ninety-seven per cent were injured during sports/recreation. Sensitivity and specificity of MRI for grade II or III MCL injury was 68% (95% CI 58–77%) and 90% (95% CI 86–93%), respectively. Weighted Kappa analysis showed moderate agreement between clinical and MRI grading (0.56 [95% CI 0.48–0.65]). Findings were similar for patients with and without concomitant cruciate ligament rupture (0.57 [95% CI 0.48–0.66] and 0.55 [95% CI 0.35–0.75], respectively) and for specialists in orthopaedics and knee sub-specialists (0.55 [95% CI 0.39–0.70] and 0.57 [95% CI 0.47–0.67], respectively). Agreement between clinical and MRI grading of MCL injuries by orthopaedic specialists in a general hospital is at least moderate regardless of the presence of cruciate ligament injury.