Cogenital double patella: two cases of a rare anatomical variant

Abstract

Abstract Congenital double patella is an exceptionally rare anatomical anomaly, with fewer than 50 cases reported in the literature. Owing to its rarity and variable anatomical presentation, diagnosis may be challenging and requires careful imaging assessment. We report two cases of congenital double patella in male patients of different ages who presented with similar clinical symptoms but markedly different anatomical configurations. In the first case, magnetic resonance imaging (MRI) demonstrated a duplicated patella associated with abnormal tendon structures and morphological alterations of the femoral condyles. In the second case, conventional radiography revealed a second fully developed patella projecting over the expected location of the patellar tendon without evidence of previous trauma. In addition to describing the imaging findings, this report discusses the principal differential diagnoses and highlights the role of diagnostic imaging in establishing the diagnosis. These cases highlight the importance of MRI and conventional radiography in distinguishing congenital double patella from acquired conditions and emphasize the clinical relevance of recognizing this uncommon anatomical variant.