We report two rare cases of complete discoid medial meniscus in the knee. Case 1 : a 28-year-old man presented with a ten-year history of left knee pain without any history of injury. On physical examination, he had no swelling or loss of motion. Case 2 : a 29-year-old woman complained of localized pain in her right knee since childhood, without any history of injury. A few days earlier, she had noticed progressively increasing pain in the affected knee, and upon presentation the knee was locked and swollen. In both cases, radiographic views showed no specific abnormalities.T2-weighted magnetic resonance imaging (MRI) of both knees revealed bilateral medial discoid meniscus with a high-intensity area in the form of horizontal tears. Arthroscopic surgery was performed on both knees, and this confirmed the tears seen on MRI. At 10 years and 6 months after surgery in both cases, neither of the patients has symptoms or loss of motion. In these cases, it was assumed that partial meniscectomy was an appropriate surgical method for treatment of complete discoid medial meniscus.
