FRACTURE-DISLOCATION OF THE TROCHLEA

The treatment of injuries about the elbow joint in young children forms an important part of the work of any traumatic unit. Fracture-separation of the capitulum is comparatively common; complete descriptions occur in the text-books, and many articles have been written on the subject. But a similar injury of the trochlea or medial condyle is unusual, and no adequate account of the condition can be found in the literature. CASE REPORTS Case 1-A girl aged eight years was referred to the Stafford General Infirmary with a history that she had had a dislocation of her right elbow reduced under general anaesthesia. No radiograph had been taken before the manipulation. A post-manipulation radiograph (Fig. 1) showed a fracture-separation of the trochlea with medial displacement and rotation-the mirror image of the more commonly displaced capitulum. The child was found to have a complete ulnar nerve palsy. One week later, open reduction of the fracture was undertaken. The large mass of the trochlea, carrying almost two-thirds of the articular surface of the lower end of the humerus, was found to be displaced and rotated medially through 90 degrees, so that the fracture surface faced medially and the articular surface laterally. Th