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. For specific instructions on the techniques to reduce common fractures and dislocations, please refer to Chapters 80 through 91.
The most common reason for a fracture to be displaced or a joint to be dislocated in a particular direction is the mechanism of injury. In the upper extremity, for example, a fall forward on an outstretched arm is the most common mechanism. Therefore, elbow dislocations occur most frequently in a posterior direction, distal radius fractures are most often Colles fractures, and supracondylar fractures are extension type fractures in 95% of cases.1
The deforming forces of muscles and ligaments also play an important role in the appearance of a fracture. Injury results in the muscles surrounding a fracture to contract or spasm. This leads to further deformity such as shortening, angulation, and rotation of the bone fragments distal and proximal to the fracture. For example, depending on the location of a humeral shaft fracture, the bone fragments will displace in different directions (Figure 79-1). 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 79-1A). Conversely, if the fracture occurs distal to the deltoid insertion, 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 (Figure 79-1B).
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 not. Reduction is more readily achieved if it occurs 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 period of time before nerve and muscle death occur. For this reason, reduction should occur as soon as possible. The earlier perfusion is restored, ...