New Findings About OCD in the Japanese

Sometimes a piece of cartilage along with a thin layer of the bone pulls away from the joint. This condition is called osteochondritis dissecans or OCD. The knee in children and young adults is affected most often. The Japanese population seems to have a higher number of cases of lateral OCD compared to other groups. In this study researchers explore the reasons for this increase.

The authors used MRIs and arthroscopy to report on the location and type of OCD in 38 knees. Most OCD occurs on the medial or inner side of the femur (thigh bone) where it meets the lower leg bone (tibia) to form the knee joint. In the Japanese groups there were more cases of lateral OCD (outside edge of the knee).

They also examined the type of cartilage or menisci present. A link between the type of OCD and the state of the lateral meniscus was found. In these Japanese patients the meniscus was described as discoid. This means that instead of a full, crescent moon shape (normal) the meniscus was a narrower but thicker crescent shape.

It appears from the results of this study that Japanese patients have lateral OCD because of the shape of the meniscus. This is different from the general European population.