Discoid meniscus in children: treatment and outcome

Discoid meniscus is an atavistic anomaly in which the meniscus of the knee, predominantly the lateral meniscus, is discoid rather than semilunar in shape. The abnormality is diagnosed relatively infrequently and may even go unrecognized or be untreated. Treatment has consisted of either partial or complete meniscectomy performed either arthroscopically or by open arthrotomy. Our purpose was to examine the outcome of treatment for discoid meniscus in children.

Since 1974, 34 children, including 2 with bilateral involvement, have been treated for discoid meniscus at the Children's Hospital of Eastern Ontario, a major pediatric referral centre. The average age of the children at the time of surgery was 11 years 4 months (range from 6 yr 2 mo-18 yr 6 mo). The average follow-up was 3 years (range from 1 mo-22 yr). The lateral meniscus was affected in 35 of the 36 knees. Treatment consisted of partial resection in 19 cases, complete resection in 13; 4 did not undergo resection.

There were 16 excellent, 10 good, 6 fair and 4 poor results at the time of most recent follow-up. In 2 cases degenerative changes were evident radiologically.

Partial resection of discoid menisci is preferable in children, but in complete dislocation of the entire menisci, total removal is necessary.