Surgical Management of Discoid Lateral Meniscus With Anterior Peripheral Instability: Retaining an Adequate Residual Meniscus Volume

Abstract

Discoid lateral meniscus (DLM) presents with differing pathoanatomy and may exhibit various types of tears. The treatment strategy is based on the presence and location of instability as a result of deficient capsular attachment. Recently, meniscal stabilization after saucerization has been recommended for DLM to preserve the meniscus shape, prevent extrusion, and mitigate against the progression of osteoarthritis. In addition to stabilization, the resection volume is important to prevent osteoarthritic changes. Although there was no tear and no displacement of the lateral meniscus on magnetic resonance imaging, some DLMs were found to have tears and peripheral instability during arthroscopy. Therefore, the assessment of peripheral instability during surgery is very important to achieve a desirable clinical outcome. This Technical Note describes an arthroscopic technique for anterior peripheral stabilization of the DLM, in which we highlight the surgical procedure for repair of the anterior horn, reassess the instability around the popliteal hiatus after the anterior horn is repaired, and the stabilization of the posterior horn, if necessary.

Fig 1

(A) Coronal, (B) sagittal, and (C) sagittal with full-extension knee magnetic resonance images of anterior instability of the discoid lateral meniscus (DLM) in the left knee. The DLM was displaced posterocentrally on the coronal image (A; white arrow), and anterior parameniscal soft-tissue edema was seen on the sagittal image (B; white arrow). The DLM is displaced posteriorly, and the posterior horn appears to be thick on the sagittal images with knee full extension (C; white arrow).

Fig 2

Arthroscopic findings of the left knee viewed from the anteromedial portal in the supine position. (A) Connective tissue (white arrow) between the anterior horn of DLM and capsule is found with arthroscopic viewing from the anteromedial portal in the flexed knee position. (B) The anterior horn of DLM (black asterisk) is moved posteriorly under knee extension. The connective tissue (white arrow) still remains between the DLM and capsule (white arrow). (C) The detached periphery of the anterior horn is found after removal of the connective tissue (white arrow). (AH, anterior horn of DLM; DLM, discoid lateral meniscus; F, femoral condyle.)

Fig 3

Saucerization of the lateral meniscus in a left knee, viewed from the anterolateral portal in the figure-four position. (A) Saucerization is started from the border between the anterior horn and central area (white arrow) of the DLM with a 45° punch from the anteromedial portal parallel to the circumferential fibers of the anterior horn of the DLM viewing from anterolateral portal. (B) Saucerization with removal of the central area (white arrow) is performed with punch from the anteromedial portal. (C) Sutures with 2-0 FiberWire are then passed through the anterior horn using a Scorpion suture passer (white arrow) introduced through the anterolateral portal. (d) A NanoPass (Stryker, Kalamazoo, MI) (white arrow) is then introduced through the anterolateral portal and used to penetrates the upper side of capsule and reach femoral side of DLM and retrieve the upper side of suture. (E) A suture is tied using a sliding knot technique and secured with a knot pusher (white arrow) through the anterolateral portal. (F) After stabilization of the anterior meniscus, the residual posterior meniscus is displaced anteriorly and appears larger (white arrow). (G) After the residual meniscus of posterior horn is remeasured, the posterior horn is resected until 10 mm from the hiatus is preserved again. (H) Meniscal instability is again evaluated with a probe. (AH, anterior horn of DLM; DLM, discoid lateral meniscus; F, femoral condyle.)

Fig 4

Additional inside-out suture of the left knee viewed from the anterolateral portal in the figure-four position. (A) The dual meniscal repair needles loaded with 2-0 braided polyester sutures (white arrow) penetrate the unstable portion of the meniscus through a cannula positioned in the anteromedial portal. (B) Arthroscopic view after saucerization with inside-out repair from the anteromedial portal.

Fig 5

Postoperative magnetic resonance imaging after saucerization with the transportal transcapsular repair for anterior instability and additional inside-out suture for consecutive posterior instability in the left knee. It resembled the normal meniscus. The width of the body of the lateral meniscus was 10 mm (A; white arrow).

Fig 6

Newly developed case of posterior instability after anterior suture only for anterior instability of DLM in the left knee. (A) Anterior parameniscal soft-tissue edema (white arrow) was seen on the sagittal MRI. (B) Arthroscopic view after saucerization with transportal transcapsular repair for anterior instability from the anterolateral portal. (C) No hiatus widening (white arrow) was seen during first surgery. (D) The DLM is displaced anterocentrally (white arrow) on the coronal image after first surgery. (E) Meniscal loss of the posterior horn around the hiatus (white arrow) was seen on the sagittal images after first surgery. (F) Hiatus widening (white arrow) was seen in the revision surgery from the anterolateral gutter view. (D, discoid lateral meniscus; F, femoral condyle; MRI, magnetic resonance imaging; P, popliteal tendon.)