[Discoid menisci in children: clinical patterns and treatment in eighteen knees]

Surgery is indicated when discoid menisci become symptomatic. The purpose of the surgical procedure is to resect any damaged tissue and restore the physiological shape of the meniscus. As a rule, as much meniscal tissue as possible must be spared because of the long-term deleterious effects on the cartilage of total meniscectomy. We analyzed a consecutive series of 18 cases of discoid menisci in children to search for secondary lesions and factors favoring their development in order to determine the optimal surgical procedure.

This retrospective series included 17 children (18 menisci) aged 7.5 years on average at diagnosis between 1985 and 2003. We noted the clinical manifestations, the imaging findings, time to treatment, and operative observations. The Watanabe classification was used to describe the discoid menisci. We also noted meniscal and cartilage damage and their consequences, as well as the consequences of late surgery on the type of procedure used.

The main complaint was pain. Physical examination usually revealed a positive pivot test. Signs of osteochondral lesions of the lateral condyle were also observed in three children, and the MRI revealed degenerative menisci in four. Mean time from diagnosis to surgical treatment was 20 +/- 17 months. The Watanabe classification was type I (n=9), type II (n=5), type III (n=4). Arthroscopy revealed nine meniscal lesions and three cartilage lesions, one associated with osteochondritis. Meniscectomy was performed in eleven cases, meniscoplasty in seven. Meniscectomy was significantly more frequent (p<0.05) when there was a meniscal lesion (9/11 of the meniscectomies) and when the time from diagnosis to treatment was long (28 months versus 8 months for meniscoplasty, p<0.01). Time to surgery was associated significantly (p<0.05) with the proportion of meniscal, chondral, or osteochondral lesions. Inversely, the type of meniscus did not affect age at diagnosis, initial manifestations, or presence of a positive pivot test.

While therapeutic abstention is warranted for asymptomatic menisci, surgical treatment should be undertaken if symptoms develop, irrespective of the type. If possible, surgery should be performed less than six months after diagnosis. The risk of secondary meniscal or cartilage injury increases with longer delay before surgery. Similarly, the chances of performing meniscoplasty are reduced with longer time from diagnosis to surgery. It must be recalled that the objective of conservative mensical surgery is to prevent secondary cartilage lesions after extensive meniscectomy and consequently the risk of osteoarthritis.