Orthopedic injuries are some of the most common presenting complaints facing the Emergency Physician (EP). Forces that cause injury can be large enough to result in fractures, displaced fractures, and joint dislocations. While each injury is different, some general principles can be applied to all displaced fractures and joint dislocations. Specific instructions on the techniques to reduce common fractures and dislocations are in Chapters 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113.
ANATOMY AND PATHOPHYSIOLOGY
The most common reason for a fracture to be displaced or a joint to be dislocated in a particular direction depends on the mechanism of injury. A fall forward on an outstretched arm is the most common mechanism of injury of the upper extremity. It results in elbow dislocations occurring most frequently in a posterior direction. Distal radius fractures occur most often as Colles fractures, and supracondylar fractures are extension-type fractures in 95% of cases.1
The deforming forces of muscles and ligaments play an important role in the appearance of a fracture. The muscles surrounding a fracture contract or spasm. This leads to further deformity (e.g., shortening, angulation, and rotation) of the bone fragments distal and proximal to the fracture. The bone fragments will displace in different directions depending on the location of a fracture (Figure 99-1). Fractures that occur between the insertions of the pectoralis major and deltoid muscles will result in a proximal humerus that is adducted from contraction of the pectoralis major muscle and a distal humerus that is abducted from contraction of the deltoid muscle (Figure 99-1A). The proximal humerus will be abducted from contraction of the deltoid muscle and the distal humerus will be adducted from contraction of the biceps and triceps muscles if the fracture occurs distal to the deltoid insertion (Figure 99-1B).
The direction of fracture displacement is influenced by muscle contraction following the injury. A. Humeral shaft fracture between the insertions of the deltoid and pectoralis major muscles. Arrows represent the direction of pull on the fracture fragments. B. Humeral shaft fracture distal to the deltoid muscle insertion.
The reduction of fractures and joint dislocations in the Emergency Department (ED) is more frequently indicated than it is contraindicated. Reduction is more readily achieved soon after an injury. No fracture benefits from a prolonged period of angulation or displacement because the reduction becomes more difficult the longer the fracture has been present. No joint benefits from a prolonged dislocation as damage to articular cartilage increases with time.
Reduction should occur on an emergent basis when perfusion to the extremity is absent. A nonperfused extremity has a finite ...