Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 5 2 2020 08 10 50 2 Soroush Baghdadi Joint Reconstruction Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran; Children's Hospital of Philadelphia (CHOP), Division of Orthopedics, Philadelphia, Pennsylvania, USA Taghi Baghdadi Department of Orthopedics, Joint Reconstruction Research Center, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran 2020 03 22 2020 04 11 Background: Congenital patellar dislocation (CPD) is a rare disorder which presents with hypoplastic and irreducible patellae. It is accompanied by flexion contracture of the knee joint, genu valgum, and external tibial rotation. Case Report: A seven-year-old girl with CPD who was misdiagnosed as having cerebral palsy (CP) crouch gait and underwent distalfemoral extension osteotomy (DFEO) without paying attention to the dislocated patellae, is presented. Recurrence ensued, and the patient was referred for further evaluation. After a second surgery to address the dislocated patellae, the flexion contracture andgait pattern improved significantly. Conclusion: The case underscores the importance of a systematic, thorough physical examination, without which uncommon diagnoses will be overlooked, exposing the patient to further morbidity and complications. https://jost.tums.ac.ir/index.php/jost/article/view/166 https://jost.tums.ac.ir/index.php/jost/article/download/166/153