MR findings of the Radial Tear of Medial Meniscus

ABSTRACT

PURPOSE: To assess 1) the characteristics and the ability of MRI to detect, 2) incidence and 3) association with preexisting lesions in the radial tears of medial meniscus MATERIALS AND METHODS: 260 consecutive arthroscopic meniscectomy was performed. Of the 260 cases, 226 cases performed knee MR images preoperatively. Two radiologic signs were used to detect 1)Cleft sign and 2) increased signal or absence of posterior meniscus (ghost meniscus). RESULTS: Forty-seven cases cases with radial tears of medial meniscus were identified(18.0%, mean age 60.5years) by arthroscopy. All of them were located in the posterior root and were full thickness tears except three cases. Thirty-four cases(72.3%) had preexisting cartilage degeneration(Outerbridge 1-4) and osteonecrosis. The sensitivity and specificity of the cleft sign and ghost sign were 72.9%, 98.8% and 93.7%, 98.8%, respectively. When combined these two criteria, accuracy was 97.7%. CONCLUSION: Radial tears located in the posterior root of the medial meniscus are common type in korea. They were frequently developed in elderly patients with preexisting cartilage damage or osteonecrosis. We can accurately diagnose the radial tear with the cleft sign and ghost sign