Diagnosis and Treatment of Discoid Meniscus

Abstract

There is a greater incidence of discoid meniscus in Asian countries than in Western countries, and bilateral discoid menisci are also common. The discoid meniscus may be a congenital anomaly, and genetics or family history may play a role in the development of discoid menisci. Because the histology of discoid meniscus is different from that of normal meniscus, it is prone to tearing. Individuals with a discoid meniscus can be asymptomatic or symptomatic. Asymptomatic discoid menisci do not require treatment. However, operative treatment is necessary if there are symptoms. Total meniscectomy leads to an increased risk of osteoarthritis. Therefore, total meniscectomy is generally reserved for rare unsalvageable cases. Partial meniscectomy (saucerization) with preservation of a stable peripheral rim combined with or without peripheral repair is effective, and good short-, mid-, and long-term clinical results have been reported.

Keywords: Diagnosis; Knee; Meniscus; Treatment.

Fig. 1

Watanabe classification. (A) The complete type is the disc-shaped meniscus that completely covers the lateral tibial plateau and has a normal posterior attachment. (B) The incomplete type has a semilunar shape and normal posterior attachment, but it covers less than 80% of the lateral tibial plateau. (C) The Wrisberg type is more normally shaped compared to the complete or incomplete type of discoid meniscus, but it lacks the usual posterior meniscal attachments (coronary ligament), and only the Wrisberg ligament connects the posterior horn of the lateral meniscus.

Fig. 2

Magnetic resonance imaging findings and arthroscopic views of the discoid meniscus according to the corresponding tear pattern. A peripheral tear refers to a longitudinal tear in the meniscocapsular junction area, anterior horn (posterocentral shift, left column), and posterior horn (anterocentral shift, middle column). The white dotted arrow (bottom, left column) shows the wide gap between the anterolateral border of the meniscus and the joint capsule. Posterolateral corner loss refers to the absence of the posterolateral portion of the discoid meniscus due to degenerative tears around the popliteal hiatus (central shift).