The Sensitivity and Specificity of Preoperative History, Physical Examination, and Magnetic Resonance Imaging to Predict Articular Cartilage Injuries in Symptomatic Discoid Lateral Meniscus

Background: Discoid lateral meniscus (DLM) is a morphologic variant in which concomitant articular cartilage defects lead to poor outcomes. The purpose of this study was to quantify the prognostic ability of history, physical examination, and magnetic resonance imaging (MRI) to identify arthroscopically confirmed articular cartilage injury in pediatric and adolescent DLM patients. Methods: An analysis of 34 consecutive patients (mean, 12.5 y) who underwent surgical treatment for DLM. Patients were grouped based on arthroscopic findings for the presence or absence of articular cartilage injury. All patients underwent standard preoperative history and physical examination, and MRI of their symptomatic knee. Separate discriminant functional analyses were performed using history (age, sex, symptoms lasting >6 mo, traumatic history), physical examination (presence of clunk, extension block, mechanical symptoms), and MRI findings (chondral injury, meniscal degeneration, meniscal morphology) to determine their sensitivity and specificity in prediction of articular cartilage lesions. Results: The sensitivity and specificity of history alone was 71.4% and 75.0%, respectively; physical examination alone was 64.3% and 60%, respectively; and of MRI findings alone was 60% and 66.7%, respectively. A stepwise discriminant functional analysis found that duration of symptoms and extension block were the optimal contributors with a 78.5% sensitivity and 80% specificity. Conclusions: Preoperative history had the highest sensitivity and specificity compared with physical examination and MRI findings for predicting articular cartilage injury at the time of DLM surgery. These findings may assist in setting expectations for patients with regard to surgical planning and recovery and also to counsel patients with asymptomatic, incidental DLM which factors may risk chondral injury and warrant early return for evaluation.