Discoid lateral meniscus has been described as a morphologically
variable anomaly, and several classifications have been proposed. We have
seen twelve patients with the so-called complete type of discoid lateral
meniscus, with intact ligament attachments as an incidental finding at the
time of arthroscopy. Ten of the twelve patients were without significant
symptoms attributable to the meniscus; that is, they had no meniscal tears
or laxity. We also have seen six patients with the Wrisberg-ligament type
of discoid lateral meniscus, in which there is abnormal meniscal mobility.
All six patients were symptomatic and had the so-called snapping-knee
syndrome, for which they had arthroscopic lateral meniscectomy. During
arthroscopy, care should be taken not to confuse the asymptomatic complete
type of discoid lateral meniscus with the Wrisberg-ligament type.