Discoid Lateral Meniscus: The Cadaveric and Arthroscopic Studies - หมอนรองข้อเข่าแบบดิสคอยด์: การศึกษาจากศพและจากการส่องกล้องข้อเข่า

Abstract

                   Discoid lateral meniscus was reported to have a higher prevalence among Asian, especially in Japanese. To date, no cadaveric study of the discoid lateral meniscus in Thai population has been reported. This study intended to find the prevalence of discoid lateral meniscus from both cadaveric and arthroscopic findings.

                   Firstly, 259 embalmed knees were dissected. The discoid lateral menisci were identified and classified into 3 types according to Watanabe classification. Secondly, 719 records of arthroscopic procedures for internal derangement of the knee performed between 1995 and 2000 were reviewed. The age, gender, presenting symptoms and arthroscopic findings of the discoid lateral meniscus cases were recorded.

                               Of 259 embalmed dissected knees, there were 11 discoid lateral menisci (4.3%). Ten of this was incomplete type. Only one knee had complete type of discoid lateral meniscus. No Wrisberg ligament type was found. Of the total 719 knees underwent arthroscopic procedures, there were 62 knees of torn lateral menisci of all kinds (8.6%). Torn discoid lateral meniscus was found in 12 knees of these 62 torn lateral menisci group (1.7% of arthroscopic cases). There were 8 incomplete and 4 complete type.

                  The prevalence of the discoid lateral meniscus in this cadaveric study was not higher than the prevalence in previous studies in Caucasians.  Although the prevalence of the discoid lateral meniscus in this cadaveric study was low, the ratio of the torn discoid lateral meniscus to the isolated tear of the normal lateral meniscus in our arthroscopic findings was as high as 1: 5. In conclusion, the discoid lateral meniscus was a common predisposing factor of a torn lateral meniscus.

Key words:  discoid lateral meniscus, meniscus injury, meniscus variation