Michael P. Kefer
PATHOPHYSIOLOGY
Bone fracture results in severing of the microscopic vessels crossing the fracture line, which cuts off the blood supply to the involved fracture edges. Callus formation ensues and becomes progressively more mineralized.
Necrotic edges of the fracture are gradually resorbed by osteoclasts. This explains why some occult fractures are not immediately detected on radiographs, but then appear several days later after this resorption process is well established.
Remodeling deposits new bone along the lines of stress. This process often lasts years.
CLINICAL FEATURES
Knowing the mechanism of injury and listening carefully to the patient’s symptoms is important in diagnosing fracture or dislocation.
Pain may be referred to an area distant from the injury (eg, hip injury presenting as knee pain).
The physical examination includes (1) inspection for deformity, edema, or discoloration; (2) assessment of active and passive range of motion of joints proximal and distal to the injury; (3) palpation for tenderness or deformity; and (4) assessment of neurovascular status distal to the injury.
Careful palpation can prevent missing a crucial diagnosis due to referred pain.
Radiologic evaluation is based on the history and physical examination, not simply on where the patient reports pain.
Radiographs of all long bone fractures should include the joints proximal and distal to the fracture to evaluate for coexistent injury.
A negative radiograph does not exclude a fracture. This commonly occurs with scaphoid, radial head, or metatarsal shaft fractures.
Diagnosis in the ED is often clinical and is not confirmed until 7 to 10 days after the injury, when enough bone resorption has occurred at the fracture site to detect a lucency on the radiograph.
An accurate description of the fracture to the orthopedic consultant is crucial and should include the following details:
Closed versus open: whether overlying skin is intact (closed) or not (open).
Location: midshaft, junction of proximal and middle or middle and distal thirds, or distance from the bone end, or intra-articular. Anatomic bony reference points should be used when applicable. For example, a humerus fracture just above the condyles is described as supracondylar, as opposed to distal humerus.
Orientation of fracture line (Fig. 171-1).
Displacement: amount and direction of distal fragment is offset from proximal fragment.
Separation: amount two fragments have been pulled apart; unlike displacement, alignment is maintained.
Shortening: reduction in bone length due to impaction or overriding fragments.
Angulation: degree and direction of the angle formed by the distal fragment.
Rotational deformity: degree distal fragment is twisted on the axis of normal bone; usually detected by physical examination and not seen on the radiograph.
Associated disruption of proper joint alignment is described as fracture-dislocation (joint surfaces have no contact) or fracture-subluxation (joint surfaces still in partial contact).
Fractures involving the growth plate of long bones in pediatric patients are described by the Salter–Harris classification (Figs. 171-2 and 171-3, and Table 171-1). Note type I and V may be radiographically undetectable.
Complications from neurovascular deficit may be immediate or delayed. Compartment syndrome that presents with the five classic signs of pain, pallor, paresthesias, pulselessness, and paralysis is well advanced.
Long-term complications of fracture include malunion, nonunion, avascular necrosis, arthritis, and osteomyelitis.
FIG. 171-1. Fracture line orientation. A. Transverse. B. Oblique. C. Spiral. D. Comminuted. E. Segmental. F. Torus. G. Greenstick.
FIG. 171-2. Epiphyseal anatomy in the growing child.
FIG. 171-3. Epiphyseal plate fractures based on the classification of Salter and Harris.
TABLE 171-1 Description of Salter–Harris Fractures
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Control swelling with cold packs and elevation. Remove objects such as rings or watches that may constrict the injury before swelling progresses.
Provide pain control.
Prompt reduction of fracture deformity with steady, longitudinal traction is indicated to (1) alleviate pain; (2) relieve tension on associated neurovascular structures; (3) minimize the risk of converting a closed fracture to an open fracture when a sharp, bony fragment tents overlying skin; and (4) restore circulation to a pulseless distal extremity (the most time critical).
Open fractures require immediate prophylactic antibiotics, irrigation, and debridement, to prevent osteomyelitis.
Immobilize the fracture or relocated joint. Fiberglass or plaster splinting material is commonly used.
The chemical reaction causing the splint material to set is exothermic and begins upon contact with water. The amount of heat liberated is directly proportional to water temperature. To avoid burns, use water slightly warmer than room temperature.
Splints should be long enough to immobilize the joint above and below the fracture.
Crutches should be prescribed for the patient with a lower extremity injury that requires prevention of weight bearing. The pressure of the crutch pads is borne by the sides of the thorax, not the axilla, to avoid injury to the brachial plexus.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 264, “Initial Evaluation and Management of Orthopedic Injuries,” by Jeffrey S. Menkes.