Method of Reducing a Backward Dislocation of the Forearm.

Fig. 83. Overextension at the elbow-the first step in the manipula

tion.

SKELETON:

Fig. 84.-Overextension.

Fig. 85.-Traction on the forearm.

Fig. 86.-Flexion.

PLATE 39.

Outward Dislocation of the Forearm and Separation of the Internal Condyle.-Fig. 1.-Anatomic specimen from a dislocation of this kind on the right arm; anterior view. The lateral displacement of the bones of the forearm is very noticeable. The articular surface of the ulna articulates with the lateral portion of the trochlea and of the capitellum humeri ; the head of the radius is outside of the joint. The separated internal condyle is attached to the ulna by the internal lateral ligament.

Fig. 2.—Same dislocation in the living subject, right arm, anterior view. There is little change in the anterior and posterior contour of the arm, but on the outer side the head of the radius forms a marked prominence. The findings are readily confirmed by palpation, especially when the forearm is rotated from pronation to supination.

Fig. 3.-Bone specimen of the same dislocation and in the same position as in figure 2, seen from the outer side. Right arm. The illustration is intended to explain figure 2.

the dislocation is recent and the swelling is not very great. It can be felt close under the skin only when there has been extensive laceration of the soft parts (brachialis anticus, nerves, and vessels). In compound dislocations it may even be seen through a tear in the skin. The line of the humerus does not end at the extremity of the forearm, as under normal conditions, but intersects it so as to leave a small portion projecting behind. Olecranon and head of the radius can be directly palpated and their excursions determined by moving the forearm. The distances between the condyles and the olecranon are abnormal. The lower end of the humerus does not present abnormal mobility as in supracondylar fracture. The humerus is shortened, and the dislocation cannot be made to disappear by drawing the forearm forward.

The diagnosis may present some difficulties in the presence of complicating injuries, such as fracture of the coronoid process. Simultaneous supracondylar fracture of the humerus and fracture of the olecranon have also been observed. In fracture of the trochlea the forearm and

Luth. Anst E Reichhold. Munchen

fragment may be displaced backward with luxation of the head of the radius.

If complications are present, they may render the prognosis unfavorable; otherwise passive and active mobility should be restored after reduction.

Treatment.-The method of reduction is shown in figures 83-86. As in every hinge-joint, reduction requires more than a simple pull, no matter how strong it may be. It must be effected without using force, as if the surgeon were toying with the joint, so to speak; anesthesia is usually required. The forearm in supination is first overextended so as to dislodge the coronoid process from the supratrochlear fossa. Moderate traction then draws the forearm forward, while the other hand seizes the injured elbow and controls the position of the parts; or the thumb may be braced against the lower end of the humerus and the other fingers, especially the third and fourth, against the head of the radius and olecranon behind, and by direct pressure assist in the act of reduction. Flexion of the arm is now found to proceed without any obstacle; the dislocation disappears and the normal contact between the articular surfaces is restored.

After-treatment according to general principles; fixation of the arm for two days, the dressing being changed at short intervals and massage administered; later passive

movements.

(b) Lateral Dislocation of the Forearm (Plate 39).— Lateral dislocations at the elbow-joint are not rare; outward dislocation is more frequent than inward, and is usually combined with fracture of the internal epicondyle. This fracture is the direct result of the contusion sustained during the fall which produces the dislocation; or it may be a sprain fracture due to the pull of the lateral ligament. It always affects the condyle furthest removed from the forearm; hence in outward dislocation the internal condyle is fractured, and, inversely, in inward dislocation the external condyle.