Arthroscopic Saucerization and Repair of a Torn Medial Discoid Meniscus

Abstract

A discoid meniscus is a congenital abnormality that usually affects the lateral meniscus, leading to instability and increased risk of tearing. A discoid medial meniscus is an extremely rare pathology that is seldom described in literature. In this report, we present the technique of operative treatment of a symptomatic, torn discoid medial meniscus. The meniscus is saucerized to 6-8 mm of stable rim, and the inside-out technique is used as the modality of meniscal fixation. Although a discoid medial meniscus is an uncommon finding, all treating surgeons should be aware of the possibility during surgical intervention.

Fig 1

Left knee, preoperative T2 MRI coronal cuts (A-C) demonstrate increased meniscal body width (red arrowheads) and sagittal cuts (D-F) show increased central thickness consistent with discoid meniscus (blue arrowheads).

Fig 2

Left knee, outside view of arthroscopic incision sites marked prior to fluid insufflation to prevent distortion. The red arrowhead marks the inferomedial portal site, the blue arrowhead marks the inferolateral portal site, and the red star marks the medial incision site.

Fig 3

Left knee, arthroscopic view through the inferomedial (A) and inferolateral (B) portals visualizing a left discoid medial meniscus. Stability is tested by placing a hook probe through the tear and pulling the posterior horn anteriorly. Anterior subluxation of the posterior horn is indicative of a meniscocapsular injury.

Fig 4

Left knee, arthroscopic view through the inferolateral portal. The lateral meniscus is visualized during the diagnostic arthroscopy to assess for any additional pathologies that need to be addressed.

Fig 5

Left knee, arthroscopic view through the inferomedial portal. The discoid medial meniscus is saucerized to 6-8 mm of stable rim using an arthroscopic punch and shaver.

Fig 6

Left knee, arthroscopic view of the saucerized medial discoid meniscus through the inferolateral portal. A hook probe (blue arrowhead) is used to assess for meniscal stability after saucerization is complete.

Fig 7

Left knee, arthroscopic view through the inferolateral portal using a 70° scope. The Guillquist maneuver can be used to better visualize the posterior horn of the medial discoid meniscus through the notch to assess meniscocapsular injury.

Fig 8

Left knee, arthroscopic view through the inferolateral portal. Vertical mattress sutures are placed posteriorly to secure the meniscus to the posterior capsule and carried on through the meniscal body as needed (blue arrowheads). Absence of subluxation of the meniscus should be noted upon completion of the repair.

Fig 9

Left knee, arthroscopic view through the inferolateral portal. An anomalous insertion of the discoid medial meniscus anterior horn on the anterior cruciate ligament.