Congenital Dislocation of the Patella.
—Zanoli1 gives an interesting study of congenital dislocations of the patella. He has observed and studied thirteen patients, forming a total of sixteen cases. The cases may be divided into two classes, permanent dislocations and habitual dislocations. He has made a study of the literature and discusses it and also various operations that have been devised. His article is illustrated by excellent photographs and roentgenograms. As regards etiology, heredity seemed frequently to be a factor. There was also a familial factor, since he noted in the literature one instance in which three sisters had the same deformity. Sex played no part. The pathology is obscure, but his conclusion is that congenital dislocation of the patella is due to an abnormal orientation of the articular axes and more precisely to an external rotation of the tibia and an inward torsion of the distal