Association between Symptomatic Discoid lateral meniscus & t
Discoid meniscus is a congenital lateral meniscus anomaly, and is more common in East Asia. It aims to evaluate the association between discoid side meniscus types and tear patterns and the causes of age-specific clinical symptoms. The study was conducted on a retrospective basis.

Of 1650 arthroscopic operations over a period of 20 years, 138 have been performed for DLM and analyzed. The DLM type was classified according to the classification of Watanabe and tear patterns were classified as horizontal, complicated, longitudinal, radial, complete and untidy by the modified Bin classification. The patients were additionally categorised as sports activities, small traumas in daily life and no traumatic episode in accordance with the causes of the onset of a clinical symptoms.

--The DLM was complete in 78 kees and incomplete in 60; no Wrisberg type DLM was observed.

--Simple horizontal and complicated horizontal tears were significantly more frequent in complete DLM, whereas radial tears and no tears were significantly more frequent in incomplete DLM.

--When classified by age group, 74 knees with DLMs were found in teenagers.

--Sports activities caused symptom onset significantly more often in teenagers, no traumatic episode caused symptom onset in patients aged less than 10 years, and minor trauma in daily living caused symptom onset in patients aged 40–59 years and more than 60 years.

--No relationship was found between the age distribution and tear patterns; however, the absence of tears tended to be more common in teenage patients, and complicated horizontal tears were more common in patients over 20 years of age.

In conclusion, in teenagers the most symptomatic DLM happened. A link between the DLM types and tear patterns was found, which could be of use in preoperative planning. Age groups were characterized in the causes of the onset of clinical symptoms in patients with DLM, which might help clinically suspect the presence of DLM.