General Principles of Orthopedic Injuries

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Chapter 49

General Principles of Orthopedic Injuries

Management Principles

Patients with orthopedic injuries and nontraumatic musculoskeletal disorders compose a large portion of the more than 100 million patients who come to U.S. emergency departments (EDs) annually. Although only rarely life-threatening, orthopedic injuries may threaten a limb or its function, and accurate early diagnosis and treatment can avert long-term complications. Many of these injuries can and should be treated definitively by the emergency physician. Consultation with an orthopedist should be sought for the treatment of most long bone fractures, open fractures, injuries with joint violation, and injuries with neurovascular compromise and for follow-up of certain patients initially treated in the ED.

Orthopedic injuries often occur as a result of accidents (industrial or otherwise) and frequently involve young, otherwise healthy, working individuals. Accurate initial diagnosis, treatment, and documentation assume great importance medically and economically. Many problems can be avoided if the following 10 general principles are kept in mind:

1. Most orthopedic injuries can be predicted by understanding the chief complaint, the age of the patient, the mechanism of injury, and an estimate of the amount of energy delivered.

2. A careful history and physical examination predict radiographic findings with a high degree of accuracy. A presumptive diagnosis before a radiographic study may prompt the physician to order special views necessary to correctly diagnose an injury. Many fractures were accurately described before the advent of roentgenology (Table 49-1).

Table 49-1

Common Fracture Names and Their Origins

Aviator’s Vertical fracture of the neck of the talus with subtalar dislocation and backward displacement of the body. First described in flyers during World War I. Arises from forced dorsiflexion of the foot in flying accidents and in traffic accidents after a head-on collision.
Barton’s Intra-articular fracture-dislocation of the wrist. Considered complicated and unstable. Requires surgical reduction in most cases. Described by Barton in 1838 before the advent of radiography.
Dorsal Barton’s Oblique intra-articular fracture of the dorsal rim of the distal radius with displacement of the carpus along with the fracture fragment. Results from high-velocity impact across the articular surface of the radiocarpal joint, with the wrist in dorsiflexion at the moment of impact.
Volar Barton’s Wedge-shaped articular fragment sheared off the volar surface of the radius (volar rim fracture), displaced volarly along with the carpus. Similar mechanism as dorsal Barton’s but with wrist in volar flexion at time of injury. Also referred to as reverse Barton’s fracture. Much rarer than dorsal Barton’s fracture.
Bennett’s Oblique fracture through base of the first metacarpal with dislocation of the radial portion of the articular surface. Usually produced by direct force applied to the end of the metacarpal. Dorsal capsular structures disrupted by the dislocation. Marked tenderness along medial base of thumb.
Bosworth Fracture-dislocation of the ankle resulting in the fibula being entrapped behind the tibia. Rare injury, produced by a severe external rotation force applied to the foot. Physical examination reveals foot severely externally rotated in relation to the tibia.
Boxer’s Fracture of the neck of the fourth or fifth metacarpal. Results from striking a clenched fist into an unyielding object, usually during an altercation, or against a wall, out of frustration or anger.
Chance’s Vertebral fracture, usually lumbar, involving the posterior spinous process, pedicles, and vertebral body. Caused by simultaneous flexion and distraction forces on the spinal column, usually associated with use of lap seat belts. Anterior column fails in tension along with the middle and posterior columns. May be misdiagnosed as a compression fracture.
Chauffeur’s Solitary fracture of radial styloid. Occurs from tension forces sustained during ulnar deviation and supination of the wrist. Name derives from occurrence in chauffeurs who suffered violent, direct blows to the radius incurred while turning the crank on a car, only to have it snap back, during previous eras.
Clay shoveler’s Fracture of the tip of the spinous process of the sixth or seventh cervical vertebra. First described in Australian clay shovelers who sustained a fracture of the spinous process by traction as they lifted heavy loads of clay.
Colles’ Fracture of the distal radius with dorsal displacement and volar angulation, with or without an ulnar styloid fracture. Most common wrist fracture in adults, especially in the elderly. Results from fall on an outstretched hand. Also known as silver fork deformity, which accurately describes the gross appearance in the lateral view. First described by Colles in 1814, before the advent of radiography.
Cotton’s Trimalleolar fracture. Fracture of the lateral malleolus, fracture of the posterior malleolus, and either a fracture of the medial malleolus or a disruption of the deltoid ligament with visible widening of the mortise on ankle radiograph.
Dashboard fracture Fracture of the posterior rim of the acetabulum. Named for mechanism of injury: a seated passenger striking the knee on a dashboard, driving the head of the femur into the acetabulum.
Dupuytren’s Fracture-dislocation of the ankle. Results from a similar mechanism as the better known Maisonneuve fracture (i.e., external rotation of the ankle), resulting in either deltoid ligament rupture or medial malleolus fracture, diastasis of the inferior tibiofibular joint, and indirect fracture of the fibular shaft. Maisonneuve was the student of Dupuytren.
Essex-Lopresti Fracture of radial head with dislocation of distal radioulnar joint. Results from longitudinal (axial) compression of the forearm.
Galeazzi’s Fracture of the shaft of the radius with dislocation of the distal radioulnar joint. Ligaments of inferior radioulnar joint are ruptured and head of ulna displaced from ulnar notch of the radius. Results from fall on outstretched hand, with the wrist in extension and the forearm forcibly pronated. Inherently unstable with tendency to redisplace after reduction.
Hangman’s Fracture-dislocation of atlas and axis, specifically of pars interarticularis of C2 and disruption of C2-3 junction. Separation occurs between second and third vertebral bodies from anterior to posterior side. Results from extreme hyperextension during abrupt deceleration. Most common cause is the forehead striking the windshield of a car during a collision. A bit of a misnomer in that hanging usually produces death by strangulation rather than cord damage.
Hume’s Fracture of the proximal ulna associated with forward dislocation of the head of the radius. Essentially high Monteggia’s injury.
Jefferson’s Burst fracture of ring of C1, or atlas. Axial loading results in a shattering of the ring of the atlas. Decompressive type of injury. Associated with disruption of transverse ligament; an unstable injury.
Jones Transverse fracture of the metatarsal base, occurring at least 15 mm distal to the proximal end of the bone, distal to the insertion of the peroneus brevis. Should not be confused with the more common avulsion fracture of fifth metatarsal styloid, produced by avulsion at the insertion of the peroneus brevis. Jones described the fracture that bears his name in 1902, after sustaining the injury himself while dancing.
Le Fort Maxillary fracture. Types I, II, and III (see Chapter 42).
Le Fort-Wagstaffe Avulsion fracture of the anterior cortex of the lateral malleolus. Rare pull-off injury of the fibular attachment of the anterior tibiofibular ligament.
Lisfranc’s Fracture located around the tarsometatarsal (Lisfranc’s) joint, usually associated with dislocation of this joint. Lisfranc, a field surgeon in Napoleon’s army, described an amputation performed through the tarsometatarsal joint in a soldier who caught his foot in a stirrup when he fell off his horse. Since then, the joint has borne his name.
Maisonneuve Fracture of proximal third of fibula associated with rupture of the deltoid ligament or fracture of the medial malleolus and disruption of the syndesmosis. Results from external rotation of the ankle with transmission of forces through syndesmosis; proximally the force is relieved by fracture of the fibula. Described experimentally in 1840, before radiography.
Malgaigne’s Fracture of the ilium near the sacroiliac joint with displacement of the symphysis, or a dislocation of the sacroiliac joint with fracture of both ipsilateral pubic rami. Resultant pelvic injury is unstable. Described by Malgaigne, based on clinical findings, in 1847.
March Fatigue, or stress, fracture of the metatarsal. Arises from long marches or other repetitive use trauma (e.g., marathon running) or less commonly from single stumbling movements.
Monteggia’s Fracture of the junction of the proximal and middle thirds of the ulna associated with anterior dislocation of the radial head. Usually caused by fall on outstretched hand along with forced pronation of forearm or by a direct blow on the posterior aspect of the ulna. Reported by Monteggia in 1814.
Nightstick Fracture of either ulna or radius, or both. Name derived from a citizen’s attempt to protect himself from a police officer’s baton or “nightstick” by offering the forearm.
Piedmont Closed fracture of the radius at the middle third–distal third junction, without associated ulnar fracture. Named for a series of cases presented at the Piedmont Orthopaedic Society of Durham, North Carolina.
Pott’s Definitions vary (see comment); most commonly a bimalleolar fracture or a fracture of the distal fibula, 4-7 cm above the lateral malleolus. The exact fracture Pott described in 1769 is uncertain; clearly it referred to a fracture of the lower fibula, usually associated with other fractures or dislocations about the ankle.
Rolando’s Intra-articular fracture at base of metacarpal. Frequently Y– or T-shaped, or may be severely comminuted. Produced by an axial load with the metacarpal in partial flexion. Worse prognosis than a Bennett’s fracture and, fortunately, rarer.
Salter-Harris An epiphyseal fracture occurring in children or adolescents. Graded I-V, depending on degree of involvement and/or displacement of epiphysis and metaphysis (see text dealing with Salter-Harris fractures and also Figure 46-1).
Smith’s Extra-articular fracture of the distal radius with volar displacement of distal fragment. Reverse of the Colles’ fracture but much more uncommon. Sometimes referred to as a “garden spade” deformity. Usually results from fall with force to back of hand. First described by Smith in 1847.
Stener Avulsion of the ulnar corner of the base of the proximal phalanx of the thumb. Bony equivalent of rupture of the ulnar collateral ligament, or “gamekeeper’s thumb.”
Teardrop Wedge-shaped fracture of the anteroinferior portion of the vertebral body, displaced anteriorly. Commonly involves a ligamentous injury and may produce neurologic injury.
Thurston Holland’s fragment Triangular metaphyseal fragment that accompanies the epiphysis in Salter-Harris type II fractures. Described by Thurston Holland in 1929. The name is commonly hyphenated, although technically it should not be.
Tillaux Isolated avulsion fracture of the anterolateral aspect of the distal tibial epiphysis. Occurs in older adolescents (12-15 years) after the medial parts of the epiphyseal plates close but before the lateral part closes. External rotation force places stress on anterior talofibular ligament. Described by Tillaux in 1872.

3. If a fracture is suggested clinically, but radiographic films appear negative, the patient should initially be treated with immobilization as though a fracture were present.

4. Criteria for adequate radiographic studies exist; inadequate studies should not be accepted.

5. Radiographic studies should be performed before most reductions are attempted, except when a delay could be potentially harmful to the patient or in some field situations.

6. Neurovascular competence should be checked and recorded before and after all reductions and after application of immobilization.

7. Patients must be checked for the ability to safely ambulate before discharge from the ED and should not be discharged unless this can be established.

8. Patients should receive explicit aftercare instructions before leaving the ED, covering such areas as monitoring for signs of neurovascular compromise or increasing compartment pressure, cast care, weightbearing, crutch use, and an explicit plan and timing for follow-up.

9. In a patient with multiple trauma, noncritical orthopedic injuries should be diagnosed and treated only after more threatening injuries have been addressed.

10. All orthopedic injuries should be described precisely and according to established conventions. When communicating with an orthopedic consultant, this may affect decisions regarding disposition of a patient and operative versus nonoperative management.


Fracture Nomenclature

Describing orthopedic injuries with precise language according to established convention enables accurate, clear communication with other parties. Terms commonly used to describe a fracture are listed in Box 49-1. A fracture is a break in the continuity of bone or cartilage. Clinically, a history of loss of function, pain, tenderness, swelling, abnormal motion, and deformity suggests a fracture. Radiographic studies are the mainstay of diagnosis and are usually, although not always, confirmatory. At times, use of special views, radionuclide bone scans, computed tomography (CT), or magnetic resonance imaging (MRI) is necessary to confirm a clinical impression. These studies should be considered when the clinical evidence is at odds with the findings of routine radiography.

General Descriptors

Description of a fracture should begin by stating whether the fracture is closed or open (less desirable terms are simple or compound). In a closed fracture the skin and soft tissue overlying the fracture site are intact. The fracture is open if it is exposed to the outside environment in any manner. This exposure may be as obscure as a puncture wound or as gross as splintered bone protruding through the skin. It is sometimes difficult to determine whether a small wound in proximity to a fracture actually communicates with that fracture. Some physicians advocate probing such a wound with a blunt sterile swab to establish a relationship; no study has established the safety, benefit, or accuracy of this maneuver. If doubt exists, an open fracture should be assumed to be present.

The next item that should be noted in the description of a fracture is the exact anatomic location, including the name of the bone, left or right, and standard reference points along the bone, for example, the humeral neck or posterior tibial tubercle. Long bones can be divided into thirds—proximal, middle, or distal—and these thirds or the junction of any two of them (e.g., the junction of the middle and distal third of the tibia) are used to describe fractures. The most descriptive language possible should be used. It is better to say “closed fracture of the right ulnar styloid” than “closed fracture of the right distal ulna” because the former conveys more precise anatomic information.

An additional modifier describes the direction of the fracture line in relation to the long axis of the bone in question. A transverse fracture occurs at a right angle to the long axis of the bone (Fig. 49-1A), whereas an oblique fracture runs oblique to the long axis of the bone (Fig. 49-1B). A spiral fracture results from a rotational force and encircles the shaft of a long bone in a spiral fashion (Fig. 49-1C). A fracture with more than two fragments is termed comminuted (Fig. 49-1D).

The position and alignment of the fracture fragments (i.e., their relationship to one another) should be described. Fragments are described relative to their normal position, and any deviation from normal is termed displacement. By convention, the position of the distal fragment is described relative to the proximal one. Displacement may be described as a quantitative measurement (i.e., in millimeters) or as a percentage of the bone width. Figure 49-2 shows a dorsal displacement of the fractured radius, and Figure 49-3 shows lateral, or valgus, displacement of the distal tibia and fibula.

The terms valgus and varus are sometimes confusing. Valgus denotes a deformity in which the described part is angled away from the midline of the body. Conversely, varus denotes a deformity in which the angulation of the part is toward the midline. Alignment refers to the relationship of the longitudinal axis of one fragment to another; deviation from the normal alignment is termed angulation. The direction of angulation is determined by the direction of the apex of an angle formed by the two fracture fragments (Fig. 49-4). This angle is opposite to the direction of displacement of the distal fragment. The relative position or angulation of the distal fragment of a fracture may also be described with terms such as radial or ulnar, dorsal or volar, anterior or posterior, and lateral or medial. One should also be aware of rotational deformity, present when the distal fragment of a fracture is rotated to some degree along the axis of the bone itself. Especially in the digits of the hand, radial or ulnar deviation of a flexed finger can occur, and radiographs often underestimate the degree of clinical deformity and rotation present.

Descriptive Modifiers

A fracture is termed complete if it interrupts both cortices of the bone and incomplete if it involves only one. It should be noted whether a fracture extends into and involves an articular surface. Frequently the percentage of articular surface involved can only be estimated; in some cases the percentage that is actually involved dictates the need to perform a surgical reduction. In general, it is important that the articular surface be restored to anatomic integrity to prevent consequent traumatic arthropathy.

Avulsion fracture refers to a bone fragment that is pulled away from its normal position by either the forceful contraction of a muscle (Fig. 49-5A) or the resistance of a tendon or ligament to a force in the opposite direction (Fig. 49-5B). Impaction refers to the forceful collapse of one fragment of bone into or onto another. In the proximal humerus, this collapse typically occurs in a telescoping manner, particularly in elderly patients, whose bones are soft and brittle. In the tibial plateau, impaction occurs frequently in the form of a depression (Fig. 49-6A and B), and in the vertebral bodies, impaction frequently occurs in the form of compression (Fig. 49-6C).

A fracture that occurs through abnormal bone is termed pathologic. A pathologic fracture is suggested whenever a fracture occurs from seemingly trivial trauma. Diseases that cause structural weakness predisposing to injury include primary or metastatic malignancies, cysts, enchondromata, and giant-cell tumors. In addition, osteomalacia, osteogenesis imperfecta, scurvy, rickets, and Paget’s disease all weaken bones, making them susceptible to fracture. The term pathologic also is applied to fractures through osteoporotic bone when the demineralization is a result of disease, as in polio. Fractures through osteoporotic bone of the elderly usually are not described as pathologic. When fractures occur in normal bones and a history of “trivial trauma” is elicited, violence or battering should be suspected. Repeated low-intensity forces may lead to resorption of normal bone, resulting in a stress fracture. Other names for this condition are fatigue fracture and march fracture (see Table 49-1). Most stress fractures occur in the lower extremities and commonly affect individuals involved in activities such as running, basketball, aerobics, and dancing. Extrinsic factors such as training regimens, type of equipment used, and nutrition habits, as well as intrinsic factors such as anatomic variation, muscle endurance, and hormonal factors have all been associated with stress fractures. These injuries may not be recognizable on initial plain films; therefore management should be based on clinical diagnosis.1 The tibia, fibula, metatarsals, navicular, cuneiform, calcaneus, femoral neck, or femoral shaft may be involved.2,3

Fracture Healing

Specific fractures are discussed in subsequent chapters. In general, the goal is to realign bony fragments so that healing or union can take place and normal function is restored. The process from fracture to union begins with a hematoma, caused by rupture of vessels crossing the fracture line. The hematoma bridges the fragments and is followed by an inflammatory phase when granulation tissue forms on the fracture surfaces. Resorption of the hematoma provides the first continuity between the fragments; however, this procallus provides no structural rigidity for bearing stress. With remodeling, callus subsequently is formed on the periosteal and endosteal surfaces of the bone, acting as a biologic splint. This area first becomes mineralized by deposition of calcium phosphate and then undergoes osseous metaplasia. Callus is resorbed as the original fracture surfaces develop firm bony union. In some bones, such as the skull and the neck of the femur, where periosteum is deficient, there may be virtually no callus formation.

Radiographic studies conducted 10 to 14 days after injury show the bone surrounding the fracture line becoming less dense because of localized bone resorption and hyperemia associated with the formation of granulation tissue. As a result, the fracture becomes considerably easier to visualize radiographically about 10 days after injury. After 2 to 3 weeks, soft tissue swelling has regressed, and callus first becomes visible, initially in a mottled pattern and then taking on a dense appearance. The callus undergoes organization, with peripheral margins becoming smooth as physically unstressed portions are resorbed.

In a healthy adult the whole process from injury to consolidation takes about 2 months for the humerus and about 4 months for a large bone such as the femur. Oblique fractures tend to heal more quickly than transverse fractures. Healing is quicker in children and slower in the elderly. The rate of fracture healing is affected by many factors, including the type of bone (cancellous bone heals faster than cortical bone); degree of fracture and opposition; and systemic states, such as hyperthyroidism or illness requiring ongoing cortiscosteroid treatment. Exercise speeds healing, whereas chronic hypoxia has been known to slow repair.

The presence of abundant callus seen on radiograph that is beginning to organize is usually associated with clinical union. If any suggestion of movement at the fracture site is noted on clinical examination, union is regarded as inadequate. Several terms are used to denote abnormal union. Delayed union is union that takes longer than usual for a particular fracture location. Malunion occurs when a residual deformity exists. Nonunion is the failure of a fracture to unite. When nonunion results in a false joint, it is termed a pseudarthrosis.

If the ends of the bone have remained constant on serial films and an adequate surrounding sheath of organizing callus can be seen, it is permissible for the patient to return to limited active use, even if the original fracture remains visible. The final process of consolidation develops later.

Fractures in Children

Certain features of children’s bones distinguish pediatric fractures from adult fractures. Bones of children are necessarily soft and resilient and sustain numerous incomplete fractures. Greenstick fractures are incomplete angulated fractures of long bones. The resultant bowing of the bone causes an appearance resembling a moist, immature branch that breaks in a similar fashion when bent (Fig. 49-7A). A torus fracture is another form of incomplete fracture, characterized by a wrinkling or buckling of the cortex. In Greek architecture a torus is a bump at the base of a column, and these fractures, occurring at the end of long bones, take on such an appearance. These fractures may be extremely subtle on radiographs (Fig. 49-7B).

Another feature of growing long bones that is a frequent source of trouble and confusion is the presence of epiphyses, cartilaginous centers at or near the ends of bone that give rise to growth of the bone. Figure 49-8 is a schematic review of the anatomy of a growing bone. Because cartilage is radiolucent, the cartilaginous portion of an epiphysis is not visualized on radiographs. A tendency exists to consider only the ossified nucleus and to ignore the cartilaginous structure that bridges to the metaphysis. Cartilage is present even before an ossified nucleus is seen. Because the epiphyseal growth plate is represented by a radiolucent line, confusion may exist as to whether a fracture line is present. These complexities in interpreting radiographs in children sometimes, but not always, require comparison radiographic views of the uninjured side. Injuries to the epiphyses may result from either compressive or shearing forces. These injuries are relatively common during childhood as opposed to sprains or shaft fractures and should be considered in children with a “sprained ankle” because of the relative weakness of the cartilaginous growth zone, which separates before stronger ligaments and bones are torn or broken. Epiphyseal injuries should be described according to the Salter-Harris classification (Table 49-2).

Type I injuries involve only a slip of the zone of provisional calcification. Comparison radiographs are usually necessary to detect small slips. Swelling and tenderness over an epiphysis (e.g., of the lateral ankle) and a negative radiograph suggest an epiphyseal injury rather than a sprain, because the epiphysis is weaker than the overlying ligaments.

Type II injuries are similar to type I injuries, with a fracture extending into the metaphysis. The triangular metaphyseal fragment sometimes is referred to as the Thurston Holland sign (see Table 49-1). Type II injuries account for approximately three fourths of all epiphyseal fractures. Because the germinal layer is not involved, growth disturbance usually does not occur with type I and II injuries. These injuries are amenable to closed reduction and immobilization without internal fixation.

Type III injuries are composed of a slip of the growth plate plus a fracture through the epiphysis, involving the articular surface. Because this fracture involves the germinal layer, growth may be disrupted. Anatomic reduction does not eliminate the possibility of growth disturbance. Type IV fractures are similar to type III fractures, with the additional involvement of a metaphyseal fracture. Open reduction and internal fixation are usually required to obtain anatomic alignment of the physis and articular surface. Growth disturbance occurs in a high proportion of patients.

Type V fractures are crush injuries of the epiphyseal plate, usually produced by a compressive force.3 This type of injury usually occurs in joints that move in one plane, most commonly the knee and ankle. Because this injury occurs in a radiolucent area, the injury may be difficult to diagnose on radiograph, but it is suggested by mechanism of injury and pain over the epiphysis. The diagnosis can be established by MRI if hemorrhage or a hematoma is identified within the growth plate immediately after injury.35 Also reported is loss of MRI signal from the cartilage.6 Rarely are type V injuries diagnosed acutely, and growth arrest manifested by shortening or angulation is the rule with this injury.

Physeal injuries occur twice as often in boys as in girls and are most common in boys aged 12 to 15 years and in girls aged 9 to 12 years.7 Distal physes are injured more often than proximal physes, and the most common anatomic locations include the distal radius, phalanges, and distal tibia. Distal radius fractures account for two thirds of fractures in pediatric patients in the ED.8 The incidence of these fractures has increased by 40% over the past three decades, possibly because of a change in recreational activities, such as increased skiing and skating among boys and increased basketball, soccer, and skating among girls.9 Most distal radius type I and II fractures can be treated through closed reduction, though this may be more technically difficult with completely displaced both-bone fractures. Similar practice has been applied to distal tibia type I and II fractures, though the incidence of premature physeal closure was shown to be 3.5 times higher if the residual fracture displacement was greater than 3 mm in postreduction radiographs.10 Growth arrest as a complication of physeal fracture is most likely to be seen at the distal femur, distal and proximal tibia, and distal radius.7

Diagnostic Modalities for Fracture Diagnosis

Plain Radiography

Conventional radiography is the mainstay in diagnosing fractures. In addition to confirming or excluding fractures, it can identify other pathologic conditions. With penetrating trauma, foreign bodies, air, and gas also may be detected. With minor trauma and when good follow-up monitoring is ensured, it is acceptable to delay radiography. Delay cannot be permitted, however, when the suggested injury is one that might be made worse by delayed diagnosis, such as a nondisplaced hip fracture.

Biplanar radiographs of an injured extremity should be obtained to fully delineate the bony injury. Conventional radiographic evaluation of long bones include at least two orthogonal views, and an oblique view is also usually obtained. In certain locations, such as the phalanges, oblique views are necessary. If doubt still exists, the clinician should ask for more views in various degrees of obliquity to the other films. A fracture line is most visible when it is parallel to the x-ray beam and is invisible when it is exactly 90 degrees to the beam. The clinician should never accept a study that examines the bone in only one plane. When a long bone is found to be fractured, it is imperative that the bone be viewed radiographically in its entire length.

Each film is examined to ensure that proper technique has been used and that no important area is omitted from the film. Overexposed films may fail to reveal an abnormality. Although some fine detail is lost on portable films, these are acceptable in unstable patients, in whom the risk of moving the patient does not outweigh the benefit of the more detailed study. Even with good technique, some fractures are not visible initially and do not appear until the margins of the fracture absorb. Absorption widens the radiolucent line, and a defect appears in 7 to 10 days. At that time, new bone produced beneath the periosteum at the margins of the fracture accentuates the fracture. Accordingly, if a fracture is suggested but not visible at the initial visit, the injury should be treated as a fracture and reexamined clinically and radiographically in 7 to 10 days, and the patient should be informed of the rationale for this regimen.

Stress views of joints are used in some instances to evaluate the degree of ligamentous injury. Some authors argue against the use of stress views, citing a risk of further injuring an already traumatized structure, additional radiation exposure to the patient and the technologist, and the possibility that pain may not allow sufficient stress to be applied. For these reasons, stress views should be used judiciously in circumstances when other methods of evaluating ligamentous injuries are not available. Comparison views are useful in selected situations but should not routinely be performed in all pediatric examinations.11 If a fracture is definitely present on the affected side, the comparison view exposes the child to radiation and adds expense with no benefit. Similarly, an experienced physician generally is able to read a normal film with reasonable certainty. It is reasonable to use comparison views in instances when radiographs are inconclusive and when the confusion arises specifically out of the need to distinguish between a possible fracture and normal developmental anatomy. Obtaining a wide field of the affected extremity is more useful than routine comparison views for a young child because the child often does not localize the pain well; this is especially true with regard to complaints of knee pain in cases of hip injury or wrist complaints in forearm and elbow injury. Comparison views sometimes are helpful in adults when a question of accessory ossicles or nonfused bones (e.g., bipartite patella) exists because these anomalies are usually bilateral. The bleeding that inevitably accompanies fractures may produce soft tissue swelling, which may impinge on or obliterate overlying muscle planes. Fat pads, such as in the elbow, may be displaced. Another useful sign is the fat-fluid level, which may accompany fractures extending into the knee joint. The fat-fluid level is visible, however, only if the cross-table technique is used.

The bones themselves should be examined systematically. Normal adult bones possess a smooth unbroken contour. A distinct angle is highly suggestive of a fracture. In an adult the typical fracture is represented by a lucent line that interrupts the smooth contour and usually extends to the opposite side. Nutrient arteries may be confused with fractures but have different radiographic characteristics: They are fine, are sharply marginated, extend obliquely through the cortex, and are less radiolucent than fractures. Pseudofractures can be created by soft tissue folds, bandages or other overlying material, or a radiographic artifact called the Mach effect. If lucencies extend beyond the bones, the line is highly unlikely to represent a fracture. Anomalous bones and calcified soft tissue likewise may be mistaken for fractures. Avulsions and small fracture fragments have an irregular surface that lacks well-corticated margins and a defect in the adjacent bone is present, whereas anomalous ossification centers (accessory ossicles) and sesamoids are characterized by smooth cortical margins. Reference texts are useful in identifying and confirming these anomalies because they tend to occur in predictable locations.12 Compression fractures are represented by increased density rather than a lucency. Finally, the most commonly missed fracture is the second fracture. One should be diligent in searching for additional fractures after discovering the first fracture on a study. In particular, certain paired fractures, such as the distal tibia and proximal fibula, should be sought out.

Special Imaging Techniques

Radionuclide Bone Scanning.: In the past, radionuclide bone scanning was used to detect skeletal abnormalities not radiographically evident in children and adults.13 Occult lesions, especially stress fractures, acute osteomyelitis, and tumors, can be detected on these scans, although there are problems with specificity and sensitivity. This modality has been largely supplanted by CT and MRI and now is seldom used.

Computed Tomography.: Computed (digital) radiography is now in widespread use. Although conventional radiography remains the initial imaging study of choice for skeletal trauma, CT offers a more detailed and diagnostically sensitive evaluation of bones and joints. With improved resolution and speed, multidetector-row CT captures large volumetric data sets from which two- and three-dimensional images can be created.14,15 Workstation postprocessing has become an integral part of the examination. Two-dimensional multiplanar reconstruction in any chosen plane, and three-dimensional surface rendering techniques provide images with unprecedented quality, even in the presence of metallic implants or fixation devices.16

CT is used to confirm possible fractures or to better define displacement, alignment, or fragmentation of fractures. It is also useful in trauma to rule out cervical spine fracture when plain films are equivocal and in noncompressive vertebral fractures to assess the number of fragments and their spatial relationship to the spinal canal. CT is used frequently to define the integrity of articular surfaces in the acetabulum, knee, wrist, or ankle and in Salter-Harris type IV fractures.4 In the multiple trauma patient requiring thoracic, abdominal, and pelvic CT imaging to rule out visceral injury, the soft tissue protocols may be adapted to acquire diagnostic bone images, as well.17 During imaging of the chest, abdomen, or pelvis, data sets are created from which the thoracolumbar spine and bony pelvis can be derived.

Complications of Fractures

Infection (Osteomyelitis)

Any fracture communicating with the surface of the skin is termed an open fracture. Open fractures are treated as true orthopedic emergencies because of the risk of infection; the dreadful nature of the complication of osteomyelitis dictates that no time should be wasted in initiating therapy (Box 49-2). Wounds should be irrigated of gross debris and covered with a sterile dressing, and parenteral antibiotics should be instituted as early as possible.20

Currently, suggested therapy includes a first-generation cephalosporin, such as cefazolin, for all open fractures, with the addition of an aminoglycoside for grade II or III fractures.21,22 Early versus delayed treatment of open fractures and its subsequent effect on rates of infection has been a source of debate. Historic guidelines recommending débridement of open fracture wounds within 6 hours of injury were based on animal experiments conducted in the 1890s.23 Current human studies suggest no clear advantage to performing surgical débridement within 6 hours of injury. The timing of débridement—less than 6 hours versus more than 6 hours after injury—had no effect on clinical or functional outcome in a prospective multicenter study of severe lower-extremity fractures.24 Other retrospective studies and literature reviews advocate early débridement and irrigation of the wound within the first 24 hours of injury to prevent infection.

Certain open fractures of the finger present a notable exception to the previous recommendation. Such injuries, especially an open distal tuft fracture, are common when the phalanx of a finger is subject to crush injury (e.g., by a door) and there exists a skin defect overlying a fractured bone. In a prospective randomized, placebo-controlled study of 193 patients with open fracture of the finger, flucloxacillin or placebo was administered to randomized patients with open phalangeal fractures, and both groups were treated with aggressive surgical irrigation and débridement. No significant difference was found in the infection rate between the groups, and no patient developed osteomyelitis. The data suggest that vigorous irrigation and débridement are adequate primary treatment for open phalangeal fractures in fingers with intact digital arteries.25 Such injuries might be repaired by the emergency physician without consultation.