Widening of the popliteal hiatus on sagittal MRI view plays a critical role in the mechanical signs of discoid lateral meniscus

Purpose This study was undertaken to elucidate the clinical significance of widening of the popliteal hiatus on magnetic resonance imaging (MRI) after a torn discoid lateral meniscus (DLM). Methods Included are 125 knees with meniscal disorders after arthroscopic surgery, divided according to preoperative MRI and symptoms into group A (torn DLM with mechanical symptoms,11 knees); group B (torn DLM without mechanical symptoms,41 knees); group C (asymptomatic DLM, 19 knees); and group D (medial meniscal tears, 54 knees). Popliteal hiatus width was measured on sagittal and coronal MRI. During arthroscopy, total meniscectomy or central partial meniscectomy combined repair of the remaining part was performed in group A and group B. Outcomes were evaluated with MRI, the Tegner, Lysholm Knee Scoring Scale, and visual analog scale (VAS) scores. Results The preoperative width of the popliteal hiatus was significantly larger in group A than in groups C and D ( P