A, Unstable 2-cm peripheral tear of meniscus. Meniscus is being repaired with stacked vertical mattress suture. B, Incomplete undersurface tear of medial meniscus; this can be treated with abrasion to stimulate local healing followed by placement of one or two sutures. C, Complete 2-cm tear in avascular zone of meniscus; this type of tear generally is treated with excision, but if repair is attempted, use of fibrin clot and other local stimuli should be considered.