Discoid lateral menisci in Japanese cadaver knees

Abstract

We undertook a descriptive, observational study to determine the prevalence of the discoid lateral menisci. The relation between the lateral meniscal shapes and the incidence of meniscal tears were studied, and the gender differences in discoid lateral menisci and the similarities of the lateral meniscal shapes in bilateral knees were examined. A total of 602 knees from 306 cadavers were macroscopically analyzed. Altogether, 577 lateral menisci were classified into the following three types: normal type (NM); incomplete discoid type (ICDM); and complete discoid type (CDM). Each lateral meniscus was examined for meniscal tears. The prevalence of a discoid lateral meniscus and gender differences in its prevalence were examined, as were the presence of a meniscal tear for the three types of lateral meniscus. In all, there were 21 (3. 6%) CDM cases and 171 ICDM cases (29.6%). The prevalence of discoid lateral meniscus, including ICDM and CDM, in the female cadavers was significantly higher than that in the male cadavers, but there was no significant gender difference in the prevalence of CDM. It was found that the shape of the lateral meniscus was similar bilaterally. The incidence of meniscal tears for ICDM was significantly higher than that for NM.

Clinical Results and Prognostic Factors of Arthroscopic Surgeries for Discoid Lateral Menisci Tear: Analysis of 179 Cases with Minimum 2 Years Follow-up

“…In the study by Ikeuchi2), a discoid lateral meniscus was observed in 16.6% of all knees examined arthroscopically during a 20 year period. In the study by Kato et al3), the prevalence was 33.2% in the 577 lateral menisci obtained from 306 cadavers. Domestically, Seong et al4) found discoid lateral meniscus in 15.3% of patients who underwent arthroscopy and Bin et al5) reported that 15.2% of patients who underwent arthroscopic meniscectomy had this variant, 67% of which were torn.…”

Symptomatic discoid lateral meniscus: a clinical and arthroscopic study in a Chinese population

“…Liu et al [ 17 ] reported that 85 % of bilateral DLM manifested homotype. However, bilateral DLM was often observed with only unilateral occurrence of symptoms [ 4 ]. Our results showed that only a small proportion of the patients with unilateral SDLM manifested bilateral symptoms in 10 years.…”

Prevalence of bilateral Discoid Lateral Menisci (DLM) in patients operated for symptomatic DLM with a follow-up study on their asymptomatic contralateral knees: a Magnetic Resonance Imaging (MRI) assessment

“…In clinical practice, we occasionally observed asymptomatic DLM in contralateral knees of symptomatic DLM patients, and their bilateral DLM often were of the same type; studies have also supported this finding. Kato et al evaluated 279 Japanese cadavers to study the shape of the menisci, and found that 91 % of DLMs were of the same morphology [ 12 ]. Therefore, when a patient presents with DLM in one knee, it is important to carefully examine the other knee.…”

“…Several clinical studies have reported bilateral DLM prevalence of between 5 and 20 % in their respective populations [ 6 , 10 , 11 ]. Among studies conducted in East Asia, Kato et al used cadaveric knees to study the prevalence of lateral discoid menisci in the Japanese population [ 12 ]. They found that bilateral menisci were of homotype (the same shape) in knees of 253 of 279 (91 %) Japanese cadavers [ 12 ], and South Korean studies reported the prevalence of bilateral DLM to be between 79 % and 97 % for patients with unilateral symptomatic DLM [ 3 , 13 ].…”