Intrasubstance meniscal tears. Clinical aspects and the role of MRI.

Forty-five athletes with the clinical features of a possible meniscus lesion underwent evaluation by magnetic resonance imaging (MRI). All the patients examined had pain in the medial or lateral compartment on effort, but at least three of the typical symptoms of a meniscus tear (effusion, restricted movement, impactions, blockades, synovial reaction) were at the same time absent. A meniscus lesion was identified on MRI in 43 patients (95.5%). Thirty-five patients (77.7%) had a pure intrasubstance tear, with a predominance of the linear grade-II lesion type (n = 31; 68.8%). Exactly this type of lesion in the posterior horn represents the most frequent cause of false-negative results in other investigational procedures (arthrography, arthrotomy, arthroscopy). In ten cases conservative treatment was performed, 28 patients had a rationale or partial meniscectomy, and in 7 cases refixation of the meniscus was performed. Forty-two patients were free of symptoms at follow-up with this treatment. The advantages of MRI in the diagnosis of a meniscus lesion are: early detection of grade-I and grade-II lesions, visualization of all the extra-articular structures, no radiation loading, noninvasive investigation, definition of a surgical intervention, possibility of monitoring the clinical course, and postoperative followup. MRI is indicated when there is a suspected significant meniscus lesion but typical symptoms are absent, in children, and in all cases where conservative treatment seems possible. In only 10% of our patients was any of these indications present. During the period of the study (4 years) we performed 489 arthroscopic operations on menisci with no additional investigations.(ABSTRACT TRUNCATED AT 250 WORDS)