Fracture of the Proximal Pole of the Scaphoid (Herbert B3)

Scaphoid fractures are the most common fracture of the carpus (80% of total), and of the wrist, the second most common after fractures of the distal radius. The typical patient is a young man injured after a fall on an extended wrist. Diagnosis of fracture is suggested by the patient's age, mechanism of injury, and symptoms. Radiographs are required to confirm diagnosis.

The scaphoid bone is anatomically unique. First, its blood supply from the superficial palmar branch of the radial artery and the dorsal carpal branch of the radial artery runs from distal to proximal, with the proximal pole receiving the most tenuous blood supply. Thus, the proximal pole is particularly susceptible to avascular necrosis as a complication of fracture. Second, its irregular three-dimensional shape presents special problems in diagnosis of acute fractures and their treatment. It is an intraarticular bone, with 80% of its surface covered with articular cartilage. Displaced fractures result in early degenerative arthritis, and malunions can lead to carpal collapse.

The scaphoid is most commonly fractured across its middle third, with 70% of fractures across the "waist." Ten percent are distal third fractures, and 20% are proximal third fractures. All proximal pole fractures should be considered unstable regardless of radiographic appearance. Russe classified scaphoid fractures into three categories based on the fracture axis: horizontal oblique, transverse, and vertical oblique. Horizontal oblique and transverse fractures together comprise ~95% of fractures, and respond equally well to therapy. Vertical oblique fractures comprise the remaining 5%, and they tend to have a slower progress to union and a higher rate of nonunion.

Optimum treatment depends on diagnosing a fracture acutely and the correct classification of the injury. CT scans greatly assist in classifying these injuries and in assessing displacement and angulation. CT scans are most useful for determining fracture union. The Herbert classification scheme for scaphoid fractures uses radiographic appearance to determine surgical versus nonsurgical management (Table 57—2). Nonsurgical management is reserved for Herbert type A fractures.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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