Fractures of the distal radius and ulna and dislocation of the proximal carpals.

Abstract

The wrist is commonly injured in falls on the outstretched hand, the character of the injury depending to a considerable extent upon the brittleness of the bones and the relative strength of the muscles and tendons upon which the forces of stress are exerted. In general, such falls tend to produce fractures of the radius and ulna in children and also in weak or elderly individuals. The same stresses in strong adults are prone to result in carpal dislocation or fracture of the scaphoid. The inherent toughness and elasticity of juvenile bones favor greenstick fracture. The brittle cortex and trabecular fragility of senile bones predispose to comminution, impaction, and T-fractures. There are endless varieties of fractures of the wrist, most of which are too well known to radiologists to justify extensive discussion here. A few are exemplified in Figure 1. We prefer descriptive adjectives to proper names in the identification of fractures. Examination The importance of adequate clinical and radiological study cannot be overemphasized. Multiple views, special views, and fine-detail technics are imperative. The use of a good magnifying lens is recommended. Films of the contralateral wrist are frequently helpful, particularly in children when the secondary centers of ossification may present problems. The radiologist should examine clinically all patients referred for radiological study. Frequently, a few well chosen questions will resolve diagnostic difficulties. We prefer to question and examine the patient after having seen the “wet films.” This is also an advantageous time for ordering special views, improving technics, and securing films of the contralateral wrist if indicated. Limitations Unrecognized Fractures: In spite of all the above precautionary measures, one may fail to demonstrate an abnormality which is clinically suspected. In such cases it is wise to treat the wrist as though it were fractured and to re-examine it in a week or ten days. This applies not only to scaphoid injuries (which are outside my province) but also to injuries of the bones and epiphyses of the forearm. Figure 2 illustrates such a “missed” fracture which was clearly demonstrated fourteen days later. Misdiagnosis of Fracture: Occasionally, sesamoid-like accessory ossicles are found in the wrist, and one is faced with the problem of differentiation between accessory bone and fracture. More than twenty carpal accessories have been described (6, 7). Although they may be mistaken for chip or avulsion fractures, careful attention to contour and reference to a chart such as is shown in Figure 3 should be helpful. The bilateral accessory pisiform bones of the nine-year-old child shown in Figure 4 has might simulate fractures of the ulnar styloids. Double ulnar styloid centers have been described (1) but are not readily confused with fractures. Double ossification centers occur infrequently in the wrist.