What triggers osteochondritis?

Decreased blood flow: The cause of osteochondritis dissecans may be a reduction in blood flow to the end part of a bone. The reduced blood supply can be from repeated small traumas (many episodes of slight injury) that damages the end of the bone. Some people may be more prone to getting osteochondritis, so there can be a genetic increased likelihood of getting it; combined with certain types of exercise or activities.

Trauma or Virus: Teitze's syndrome.