Review Question - QID 212129

Of the above, the most likely plain radiography finding of the affected knee in patient with a discoid lateral meniscus is squaring of the lateral femoral condyle (answer choice 5), though normal findings are most commonly observed, overall.

Radiographs are normal in most children with a discoid meniscus. Less common radiographic findings that are indicative of severe discoid menisci include squaring of the lateral femoral condyle, cupping of the lateral tibial plateau, and widening of the lateral joint line. MRI of the knee has been demonstrated to be the most sensitive for identifying discoid menisci. The presence of a contiguous central meniscus on three consecutive slices is usually indicative of the diagnosis.

Kramer et al. reviewed the diagnosis and treatment of meniscal tears and discoid meniscus in children. They reported that discoid menisci represent a spectrum of morphologic abnormalities and instability of the lateral meniscus, most commonly. They highlighted that highly unstable variants often present with the classic snapping knee syndrome, while stable variants may remain asymptomatic until a tear develops. They recommended that symptomatic discoid menisci should be observed, and that symptomatic types be treated with saucerization and repair.

Good et al. reviewed the operative results of children and young adults treated arthroscopically for symptomatic discoid lateral menisci. They reported that arthroscopic saucerization was successful in 28 of 30 knees, with 2 cases (large complex tears precluding meniscal salvage) requiring complete arthroscopic meniscectomy. They concluded that arthroscopic saucerization and repair has good short-term efficacy in cases of symptomatic discoid menisci.

Incorrect Answers:
Answer 1: A shallow intercondylar notch has been associated with ACL injuries, not discoid menisci.
Answer 2: Lateral joint space widening (not narrowing) may be seen with discoid menisci.
Answer 3 and 4: Squaring of the lateral femoral condyle and cupping of the lateral tibial plateau may be seen in cases of severe discoid menisci.