[Posterior defects of the patella on CT arthrograms. Detection and differential diagnosis]

Changes of the posterior bony and cartilaginous surfaces of the patella as seen on CT arthrograms are described in the case of bipartite patellae, fractures and ossification defects. Contrary to present opinion, cartilaginous lesions are frequently seen on CT arthrograms. This is also true for discreet and partial ossification defects which are not visible on conventional x-rays and are described here for the first time. The aetiology, morphogenesis and clinical examples are discussed.