Discoid medial meniscus: two cases of tears presenting as locked knee due to athletic trauma.

Two patients with a rare, massive type of discoid medial meniscus have been described. Both presented with a locked knee due to athletic trauma in the third and fifth decade of life, respectively. Clinically, discoid meniscus has only nonspecific signs. The arthrogram has proved to be a helpful preoperative diagnostic tool. Definitive diagnosis and treatment can be made with arthroscopy.