Arthroscopic views of the medial meniscus. (a) Degenerated horizontal tear of the middle and posterior segments was identified. (b) An introducer needle was inserted at the most peripheral site to the torn meniscus. (c) Massive bloody viscous fluid exploded from the small channel between the upper and lower leaf of the torn meniscus with disappearance of the medial large mass. (d) A small channel is indicated by arrows.
