Magnetic Resonance Imaging Findings of Surgically Proven Medial Meniscus Root Tear

Abstract

OBJECTIVE: To evaluate magnetic resonance imaging (MRI) findings of medial meniscal root tear and the correlation of medial meniscal root tear with other associated knee abnormalities. METHODS: We retrospectively assessed preoperative magnetic resonance images of 39 patients with arthroscopically confirmed medial meniscal root tear. Magnetic resonance imaging findings were retrospectively reviewed by 2 experienced musculoskeletal radiologists for consensus. We evaluated the configuration of meniscal root tear and the other associated knee abnormalities on MRI for direct correlation with arthroscopic findings. RESULTS: At arthroscopy, there were 36 radial tears and 3 complex tears involving the medial meniscal posterior horn roots. All 36 radial tears could be correctly diagnosed by MRI, with findings showing ghost sign on sagittal images in 100% (36/36), vertical linear defect on coronal images in 100% (36/36), and radial linear defect on axial image in 94% (34/36). However, all 3 complex tears were misdiagnosed as radial tears on MRI. Medial meniscal root tears displayed a strong association with degenerative joint disease in 97% (38/39). Medial meniscal root tears were also found in association with cartilage defects of the medial femoral condyle and medial meniscal extrusions (> or =3 mm) in 89% (34/38) and 67% (26/39), respectively. CONCLUSIONS: Medial meniscal root tears were usually posterior horn root radial tear. A high association with degenerative joint disease, cartilage defects of the medial femoral condyle, and medial meniscal extrusions (>/=3 mm) were also noted.