Bipartite Patella: Magnetic Resonance Imaging

Objective: Bipartite patella is accepted as a normal anatomic variant of patella,\udand is identified incidentally on knee radiographs taken for other reasons. The aim\udof this study was to characterize the magnetic resonance imaging (MRI) features\udof bipartite patella without bone marrow edema.\udMaterials and Methods: In total, 1.000 patients were evaluated retrospectively.\udImaging was performed on 1.5T MRI unit using extremity coil. A standardized\udknee protocol was used. The obtained images were thereafter analyzed by two\udexperienced radiologists in consensus.\udResults: Of the 18 patients, six were female and twelve were male. The mean age\udof the group was 42.1±23.5 years. The bipartite fragments were located in the\udsuperolateral aspect of the patella. In 16 knees, only one fragment was recognized.\udThe average transverse diameter of the patellar fragment was 11.6±8.1 mm. In the\udaxial plane, the average distance between the fragment and the main patella was\ud1.67±1.1 mm. Continuity of the patellar cartilage on the fragment was observed in\udall patients. The mean fragment cartilage thickness was 1.9±1 mm and the patellar\udcartilage thickness was 3.8±2.3 mm. Cartilage signal was present in ten knees, fluid\udsignal was present in six knees, and fibrous signal was present in four knees in the\udsynchondrosis region.\udConclusion: A defining feature of bipartite patella without accompanying edema\udin the bone marrow is a thinner-thannormal\udcartilage covering the fragments, and an overall cartilage signal over the\udarea of the synchondrosis. \u