With this case report, we introduced a rare and commonly overlooked cause of lateral snapping knee, a snapping popliteus in a 14-year-old female patient. She was initially treated for a lateral discoid meniscus, a common diagnosis in this age group. Because of the non-resolving symptoms, a second-look arthroscopy was performed and showed a popliteus tendon snapping over a tubercle on the lateral femoral condyle. Resection of the tubercle resulted with a successful outcome. In evaluating the snapping knee in young children, popliteus tendon should be kept in mind. Key words: snapping popliteus, tubercle, knee, arthroscopy, popping.

Department of Orthopedics and Traumatology Izmir University of Health Sciences Tepecik Training and Research Hospital Izmir Turkey