Developmental Anomaly of Patella Frequently Diagnosed as Fracture.
—Adams and Leonard1 call attention to the fact that the patella is a sesamoid bone and thus subject to congenital anomalies that may be mistaken for fractures. Congenital anomalies of the patella are more common than has generally been supposed. In a series of sixtythree cases of fractured patella during one year, more than 3 per cent were congenital anomalies erroneously diagnosed. The differential diagnosis between a congenital anomaly and fracture can easily be made from a roentgenogram. These deformities are usually bilateral. The adjacent surfaces of the bone are smooth and consist of cortical bone. The congenital anomalies are located in the outer and upper quadrant, which is a rare location for fracture. The absence of a typical clinical history and the symptoms usually associated with fracture should make the examiner suspicious that he is dealing with a