A case report of discoid medial meniscus injury with discoid lateral meniscus.

An 11-Year-old boy, previously asymptomatic, sustained a twisting injury to the left knee while playing baseball in December 1983.After ten months, he still had pain and was unable to extend the knee fully.He was admitted to our hospital on October 8, 1984. Physical examination reveaiea the knee to be locked in 10 degrees of flexion and medial joint-line tenderness and a click of the McMurray maneuver.Arthrogram revealed a tear of a medial meniscus and a lateral discoid meniscus.Arthroscopy and Arthrotomy were done on November 5, 1984.Arthroscopy revealed a medial discoid meniscus and a lateral discoid meniscus, but there were no tears on the lateral meniscus.Arthrotomy comfirmed that there was a horizontal tear of a medial discoid meniscus.The medial meniscetomy was performed and the patient had a complete recovery after 3 months.