Arthroscopic Visualization of Abnormal Movement of Discoid Lateral Meniscus With Snapping Phenomenon.

Discoid lateral meniscus with snapping phenomenon is a rare pathologic condition. The purpose of this article is to present an arthroscopic technique for the treatment of discoid lateral meniscus with snapping phenomenon. The patient is placed in the supine position for confirmation of snapping. As the patient's knee bends, it can be confirmed by arthroscopy that the posterior horn of the discoid lateral meniscus moves posteriorly and the central portion of the discoid lateral meniscus moves anteriorly at the same time with snapping at deep flexion angles. The anterior segment of the discoid lateral meniscus is found to be redundant and is often folded. On the contrary, as the patient's knee extends, the central portion is returned to the original position accompanied by snapping at nearly full extension. After excision of the central portion, the movement of the meniscus is evaluated again and the disappearance of the snapping phenomenon can be confirmed. Although it includes limitations, this application is easy and would certainly help surgeons to treat snapping knee with discoid lateral meniscus.