Abstract

Double patella is a rare condition, usually unsuspected during clinical evaluation. We report the case of a 64-year-old male who consulted for knee pain. The radiograph and ultrasound suggested a double patella in the coronal plane that was con-firmed by magnetic resonance imaging (MRI). The patella is the largest sesamoid bone and could have multiple alterations of its development, which are relatively frequent. It can have variations in its ossification shape, position and hypoplasia, but congenital duplication is an uncommon finding in clinical practice, especially in the coronal plane. MRI is the best imaging option because it allows multiplanar evaluation and has a high tissue contrast, which allows better recognition of a second independent structure. We review the literature and illustrate a classification of the double patella, which must be considered among the differential diagnoses of congenital, traumatic and degenerative conditions.