Clinical significance of intrasubstance meniscal lesions on MRI.

Grade 2 meniscal changes on MRI are linear signals confined within the meniscus thought to represent areas of meniscal degeneration or intrasubstance tears. It has been reported that in only 10% of cases is a meniscal tear detected during subsequent arthroscopy. Usually non-operative management is appropriate, but in some cases, grade 2 meniscal changes are seen on MRI in patients with a typical presentation of a meniscal tear. In this circumstance, an arthroscopic partial meniscectomy may be indicated and an MRI report, which describes the meniscus as being normal, may be confusing. A pilot study of 10 consecutive symptomatic patients (mean age 28.1 years) with a grade 2 meniscal signal on MRI was performed. At arthroscopy, with thorough examination of the meniscus using a probe, an intrasubstance tear was detected in all 10 patients. Partial meniscectomy was performed, with a mean follow-up of 6.7 months. All but one patient (due to other pathology) had marked improvement in pain and function. Thus, the authors believe that grade 2 signal changes should be reported in a manner that raises the possibility that they may cause symptoms and that the presence of any intrasubstance changes should be clearly conveyed in the report.