Chapter 1: General Principles

Biomechanics

An orthopedic fracture occurs when the stress applied to a bone exceeds the plastic strain beyond its yield point. A number of factors influence fracture patterns. These include the magnitude of force, its duration and direction, and the rate at which it acts. When a bone is subjected to repeated stresses, the bone may ultimately fracture even though the magnitude of one individual stress is much lower than the ultimate tensile strength of the bone. The strength of a bone is related directly to its density, which is reduced by any condition, such as osteoporosis, where the osseous structure is changed, thus lowering its resistance to the stress.

Terminology

Fractures can be described in a number of ways. No one system of classification is all-encompassing, and physicians dealing with fractures on a day-to-day basis must be aware of the terminology to better understand and convey information to their colleagues. It should be noted that to adequately describe a fracture, at least two perpendicular radiographic views should be obtained.

Direction of Fracture Lines

• Transverse: A transverse fracture runs perpendicular to the bone (Fig. 1–1A).

• Oblique: An oblique fracture runs across the bone at an angle of 45 to 60 degrees (Fig. 1–1B). These fractures are due to compression and flexure at the fracture site.

• Spiral: A spiral fracture may be misdiagnosed as an oblique fracture; however, on closer study, a “corkscrew” appearance of the fracture is noted (Fig. 1–1C). It is a highly unstable fracture that is prone to poor healing. Spiral fractures are due to a torsional force. In pediatrics, a spiral fracture of the femur in a nonambulatory child is suspicious for nonaccidental trauma. However, a spiral fracture of the distal tibia in an ambulatory child is common and referred to as a “toddlers fracture.”¹

• Comminuted: A comminuted fracture is any fracture where there are more than two fragments (Fig. 1–1D). Other examples of comminuted fractures are the segmental and butterfly fractures (Fig. 1–1E and 1–1F).

• Compression: A compression fracture is one where the fractured ends are compressed together. These fractures are usually very stable (Fig. 1–1G). Compression fractures, also referred to as impacted fractures, are common in the vertebral bodies and lower extremities (e.g., calcaneus, femoral neck, and tibial plateau). When compression is significant, the fracture may become “depressed”, or pushed in, and is referred to as a depression fracture (e.g., depressed calcaneus fracture).

Anatomic Location

• In a long bone, fractures are categorized as being in either the proximal, middle, or distal portions of the bone.

• If the fracture extends into the joint space, it is described as intra-articular. Fractures that do not involve the joint are extra-articular.

• Other anatomic terms used to describe the location of a fracture are the head, neck, shaft, and base (e.g., metacarpal and metatarsal fractures).

• In pediatrics, fractures are described in relation to the growth plate (physis). Fractures that occur between the joint and the growth plate are epiphyseal fractures. Fractures of the diaphysis refer to the shaft of the bone. The metaphysis is the zone of growth of a bone between the epiphysis and the diaphysis.

Displacement

Displacement is used to describe the movement of fracture fragments from their usual position. Other terms that further describe fracture movements include:

• Alignment is the relationship between the axes of the bone fragments. To measure alignment, draw an imaginary line through the normal axis of the fractured proximal segment and then another line through the axis of the fractured distal segment, measuring the angle produced by the two lines. Alignment is described in degrees of angulation of the distal fragment in relation to the proximal fragment (Fig. 1–2). Lateral angulation of the distal fragment is also known as valgus deformity, whereas medial angulation is varus deformity. Angulation in the anteroposterior (AP) plane is referred to as volar and dorsal. Volar angulation of a distal fragment would be termed “volar angulation.” Some orthopedists describe angulation based on the apex of a fracture. Therefore, “volar angulation” could also be described as “apex dorsal angulation.”

• Apposition describes the amount of contact between the fracture surfaces (Fig. 1–3). Apposition may be complete, partial, or absent (no contact).

• Translation is used to describe movement of fracture fragments from their usual position in a direction perpendicular to the long axes of the bone. Translation is described as a percentage of the bone’s width. The direction of translation is described on the basis of the movement of the distal fragment in relation to the proximal fragment. In clinical practice, however, it is more common to use the more general term “displacement” to describe translation. For example, the fracture shown in Figure 1–3A would be described as being 50% displaced in a lateral direction.

• Bayonet apposition is present when the fragments are not only 100% displaced but also overlapping (Fig. 1–3B). This is frequently seen in femoral and humeral shaft fractures.

• Distraction is the term used when the displacement is in the longitudinal axis of the bone (i.e., the bone fragments are “pulled apart”) (Fig. 1–3C).

• Rotational deformity can occur in any fracture although it is common after spiral fractures. It can be detected clinically when radiographs reveal a nondisplaced fracture yet the extremity appears abnormal, such as a finger pointing in the wrong direction. Subtle rotational deformity is detected by noting that the diameter of the bone on either side of the fracture line is different.

Soft-Tissue Injury

• Closed: A fracture in which the overlying skin remains intact.

• Open: A fracture in which the overlying skin is disrupted.

• Complicated: A fracture associated with either neurovascular, visceral, ligamentous, or muscular damage. Intra-articular fractures are also considered complicated.

• Uncomplicated (simple): A fracture that has only a minimal amount of soft-tissue injury.

Stability

• Stable fracture: A fracture that does not tend to displace after reduction. Transverse fractures are frequently stable fractures.

• Unstable fracture: A fracture that tends to displace after reduction. Comminuted, oblique, and spiral fractures are more commonly unstable.

Mechanism of Injury

• Direct forces typically cause transverse, oblique, or comminuted fractures. An example of a direct force causing a fracture is the nightstick fracture via direct blow to the ulna. A comminuted fracture following a crush injury and a fracture due to high-velocity bullet are also caused by direct impact.

• Indirect forces may also induce a fracture by transmitting energy to the bone. An example is the avulsion fracture due to ligamentous traction (Fig. 1–4A). A force, such as valgus stress at the knee, can result in a compression or depression fracture of the tibial condyle (Fig. 1–4B). A rotational or torsional force applied along the long axis of a bone results in a spiral fracture. A stress fracture, sometimes referred to as a fatigue fracture, results from repeated indirect stress applied to a bone. Some stress fractures are caused by repeated direct trauma.

Joint Injury

• Dislocation: Total disruption of the joint surface with loss of normal contact between the two bone ends (Fig. 1–5A).

• Subluxation: Disruption of a joint with partial contact remaining between the two bones that makes up the joint (Fig. 1–5B).

• Diastasis: Certain bones come together in a syndesmotic articulation in which there is little motion. An interosseous membrane that traverses the area between the two bones interconnects these joints. Two syndesmotic joints occur in humans between the radius and ulna and between the fibula and tibia. A disruption of the interosseous membrane connecting these two joints is called a diastasis (Fig. 1–5C).

Communication

The proper use of the terms provided above to communicate with the orthopedic specialist is one of the most important aspects of orthopedic care performed by the emergency physician. In addition to fracture description, indicate the mechanism of injury, contamination of the injury, and overall patient status. A simple mnemonic to describe the fracture itself is NOLARD:

• Neurovascular status

• Open versus closed

• Location

• Angulation–Alignment–Articular involvement

• Rotation

• Displacement²

Fracture Healing

Fracture healing can be divided into three phases—inflammatory, reparative, and remodeling (Fig. 1–6). Initially, after a fracture occurs, a hematoma forms at the site between the fracture ends and rapidly organizes to form a clot. Damage to the blood vessels of the bone deprives the osteocytes at the fracture site of their nutrition and they die. With this necrotic tissue, the inflammatory phase of fracture healing begins, accompanied by vasodilatation, edema formation, and the release of inflammatory mediators. In addition, polymorphonuclear leukocytes, macrophages, and osteoclasts migrate to the area to resorb the necrotic tissue.

The reparative phase begins with the migration of mesenchymal cells from the periosteum. These cells function to form the earliest bone. Osteoblasts from the endosteal surface also form a bone. Granulation tissue invades from surrounding vessels and replaces the hematoma. Most healing occurs around the capillary buds that invade the fracture site. Healing with new bone formation occurs primarily at the subperiosteal region; cartilage formation occurs in most other areas. Osteoblasts are responsible for collagen formation, which is then followed by mineral deposition of calcium hydroxyapatite crystals. A callus forms, and the first signs of clinical union are noted.

During the remodeling phase, the healing fracture gains strength. As the process of healing continues, the bone organizes into trabeculae. Osteoclastic activity is first seen resorbing poorly formed trabeculae. New bone is then formed corresponding to the lines of force or stress.

An important concept to optimal fracture healing is strain. Insufficient strain or load may cause removal of the callus with delayed union (healing of a fracture that takes longer than expected) or nonunion (a fracture that does not heal). Excessive strain (e.g., weight bearing too early) can endanger the fracture healing process by causing fracture of callus formation. Several mechanisms influence healing including the fracture geometry as well as the type and degree of fragment movement. These factors influence the mechanical and biological signals for fracture repair.³

Many terms are used to describe fracture healing. Union refers to the healing of a fracture. Clinical union permits the resumption of motion of a limb and occurs earlier than radiographic union. Radiographic evidence of union is present when bone bridging of the fracture is seen on at least three cortices on orthogonal projections. Exercise increases the rate of repair and this should be encouraged, particularly isometric exercise around an immobilized joint.

Malunion is the healing of a fracture with an unacceptable residual deformity such that angulation, rotation, or overriding fragments result in shortening of the limb. Shortening is better tolerated in the upper extremities (humerus) than lower extremities (femur or tibia). Generally, shortening greater than 1 inch is poorly tolerated in the lower extremity.

Delayed union is healing that takes a longer time than is usual. Delayed union is evident when periosteal new bone formation stops before union is achieved. In a long bone, delayed union is present if it has not fully united within 6 months.

Nonunion is defined as failure of the fracture to unite. The two most common reasons for fracture nonunion are an inadequate blood supply and poor fracture stabilization. Inadequate blood supply may be due to damaged nutrient vessels, stripping or injury to the periosteum and muscle, severe comminution with free fragments (butterfly and segmental fractures), or avascularity due to internal fixation devices. The amount of contact between the bone ends (apposition and distraction) and associated soft-tissue injuries adversely affect the rate of healing because the framework for bone repair is damaged.

The location of the fracture may impact the likelihood of nonunion. Cortical bone found in tubular bone diaphyses heals at a slower rate than does the cancellous bone in the epiphyses and metaphyses due to the differences in vascular supply and cellularity. Bones that have a higher incidence of nonunion include the distal tibial diaphysis, scaphoid, and proximal diaphysis of the fifth metatarsal.

Other causes of nonunion include soft-tissue interposition, bony distraction from traction or internal fixation, infection, age, fractures through pathologic bone, and medications. Patient age is a factor as children experience a higher affinity for rapid bone remodeling. The healing of intra-articular fractures is inhibited by exposure to the synovial fluid. The synovial fluid contains fibrinolysins that retard the initial stage of fracture healing causing lysis of the clot. Certain drugs, such as corticosteroids, excessive thyroid hormone, and nicotine from cigarette smoke inhibit the rate of healing. Chronic hypoxia and nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to inhibit bone healing in animal studies.

Pseudoarthrosis results from an untreated and grossly mobile nonunion. In pseudoarthrosis, a false joint with a synovial-lined capsule appears that envelopes the fracture ends.

Clinical Features

Pain and tenderness are the most common presenting complaints associated with a fracture. Symptoms are usually well localized to the fracture site, but can be more diffuse if there is significant associated soft-tissue injury. Loss of normal function may be noted, but in patients with incomplete fractures (e.g., stress fracture) the functional impairment may be minimal. When the fractured ends are in poor apposition, abnormal mobility and crepitation may be elicited. These findings should not be sought on examination as they increase the chance of further soft-tissue damage. Patients with gross deformity or crepitation should be splinted immediately before they are moved or any radiographs are performed.

Point tenderness should be noted whenever it is elicited. A stress fracture may be tentatively diagnosed or suspected on the basis of bony tenderness even though a fracture might not be seen on radiographs for 10 to 14 days. In a similar manner, when evaluating a patient with an injury to a joint, consider an osteochondral fracture as the cause of pain.

No examination of a patient with a suspected fracture is complete without a neurovascular assessment. Injury to nerves and vessels should be documented and addressed where appropriate before any attempts at reduction. Furthermore, signs of compartment syndrome should be elicited such as spontaneous, intense, or “out of proportion” pain, enlarged or tense compartments, or pain on stretching of the muscles within the compartment. Paresthesias, poikilothermia, pulselessness, or paralysis may also be present, but occurs later.⁴

A close examination of the skin is necessary to exclude an open fracture. The injury to the skin may seem innocuous, but when present near the site of a fracture and the base of the wound it cannot be identified; the injury should be considered an open fracture until proven otherwise (Fig. 1–7).

Evidence of blisters over a fracture site is not uncommon when swelling is severe. Fracture blisters may appear as early as 6 hours after a fracture. They may be clear or hemorrhagic. Hemorrhagic blisters indicate detachment between the dermal and epidermal layers and an associated worse prognosis (Fig. 1–8). Fracture blisters are most common in areas with bony prominences such as the elbow, foot, and distal tibia. Early reduction and stabilization of fractures decreases the incidence of blister formation, although they may form even when care has been optimal. Edema control with compression, elevation, and cryotherapy are also useful. The treatments for fracture blisters are controversial although most authorities leave them intact and cover them with povidone-iodine, antibiotic ointment, or silver sulfadiazine dressing. Their presence frequently delays operative repair because they double the rate of infection and wound dehiscence.

Bleeding is another potential problem following fractures, especially in long bones (eg, femurs) and the pelvis. A significant amount of blood loss can occur after a closed fracture and the amount of bleeding is often not appreciated (Table 1–1). A patient with a significant pelvic fracture can experience shock from blood loss. This is especially true in the elderly who are less able to vasoconstrict to support their blood pressure.

Radiographs

Plain radiographs are usually sufficient for fracture diagnosis. Fractures appear as a disruption of the smooth cortex of the bone with a radiolucent line delineating the fragments (Fig. 1–9). Acute fractures are usually linear with irregular borders. Compression fractures are more difficult to detect and are noted when there is a loss of the normal trabecular pattern within the bone and when the bone appears more radiodense (Fig. 1–10).

Avoid treating accessory ossicles (i.e., sesamoid bones) as avulsion fractures by looking for their smooth border. When doubt exists, a comparison view of the opposite extremity can be obtained, although it should be noted that sesamoid bones are not always symmetric. The fabella of the knee, for instance, is bilateral in only 63% of people.

Two orthogonal views (AP and lateral) are obtained at a minimum. This serves to improve the rate of fracture diagnosis and to give the clinician a full understanding of the displacement of a fracture (Figs. 1–11 and 1–12). Additional views should be requested in select situations. Oblique views, for instance, are particularly helpful when imaging the distal extremities (e.g., hand, wrist, foot) and increase the sensitivity of fracture detection.

Radiographs should include the joint above and below the fracture. This is useful to detect distant fractures that may be less symptomatic than the primary injury. For example, a medial malleolus fracture is commonly associated with a proximal fibula fracture in the Maisonneuve fracture pattern. Additionally, rotational deformities can be detected when joints are present in the radiographs of a long bone fracture. An AP view of one joint and a lateral view of the other joint suggests a significant rotational deformity (Fig. 1–13). Finally, shortening of one of the bones of the forearm or leg because of angulation or bayonet apposition suggests that another fracture is present in the other bone (e.g., tibia–fibula fracture) or there is a joint dislocation (e.g., Monteggia fracture). These concomitant injuries will be diagnosed when the entire length of the long bone(s) and their proximal and distal joints are seen on radiographs.

A fracture may occur and not be radiographically evident for up to 2 weeks postinjury (Fig. 1–14). For this reason, the emergency physician should practice with the guideline that if there is significant trauma and focal bony tenderness suspicious of a fracture, it should be treated as such. This is especially true in the pediatric patient with pain over a growth plate.

There are some regions where occult fractures occur quite commonly and are frequently missed. The scaphoid is an example, as it is notorious for occult fractures (10%–20%) that are not radiographically visible for several weeks after injury. Occult fractures of the hip occur in close to 5% of elderly patients with trauma, hip pain, and negative initial radiographs.

When an occult fracture is suspected, the clinician should consider other diagnostic studies such as magnetic resonance imaging (MRI) and computed tomography (CT) scan. These imaging techniques have a much higher sensitivity for fracture detection. MRI has been shown to be close to 100% sensitive for diagnosing occult fractures of the scaphoid or hip. When further imaging is not obtained in the emergency department, splint the patient for the mere suspicion of such a fracture, even though it is not radiographically visible, and arrange orthopedic follow-up.

Treatment

Prehospital Splinting

An unstable fracture must be stabilized by some form of external splinting or traction before movement of the patient. Proper splinting in the prehospital setting reduces pain and prevents further soft-tissue injury by the fracture fragments. A neurovascular examination should be performed both prior to splinting and immediately afterward.

A traction splint for a femur fracture is one of the most important splints to be placed in the prehospital setting. After a femur fracture, the overriding bone results in loss of soft-tissue tension in the thigh and an increased potential space for hemorrhage. Up to 1 L of blood can distend the soft tissues of the thigh. A traction splint maintains tension on the soft tissues, decreases the amount of hemorrhage, and subsequently improves outcome.⁵

Perhaps the oldest known lower-extremity traction splint is the Thomas splint. This splint has been used since the late 1800s and became famous during World War I when mortality was reduced by 50% after its introduction into battle.^5,6 A modification of this splint is the Hare traction splint, in which a half-ring makes up the most proximal portion (Fig. 1–15). These splints provide traction of the fracture fragments, but cause a great deal of discomfort during transport. The splint should not be removed before radiographic evaluation.

The Sager traction splint (Minto Research and Development, Inc.) is our preference for emergency splinting of all proximal femur and femoral shaft fractures in both the pediatric and adult age groups (Fig. 1–16). The Sager splint has a single shaft that is placed on the inner aspect of the leg, but can be applied to the outer side of the leg if a pelvic fracture is present. The splint does not have a half-ring posteriorly, which has two important advantages⁵: (1) it relieves any pressure on the sciatic nerve and⁶ (2) it reduces hip flexion (which occurs up to 30 degree in the Hare splint), thereby eliminating angulation of the fracture site.

Several other traction splints are available in the prehospital, tactical, and military venues such as the Faretec CT-6 Military Leg Traction Splint (Faretec, Inc.), the Slishman Traction Splint (Rescue Essentials), and the Tactical Traction Splint (North American Rescue). Following similar principles, these splints offer lightweight options in tactical or military operations as well as in austere environments.

Other commercially available extremity splints include the SAM^® splint (SAM Medical Products, Inc.), Fox splint (Compliance Medical, Inc.), wire ladder splints, and inflatable splints. The SAM^® splint, made of malleable foam covered aluminum, is lightweight, easy to use, and conforms well to the extremity. The Fox splint consists of cardboard and foam rubber, therefore lacking malleability. Inflatable splints made of a double-walled polyvinyl jacket and ladder splints made of a moldable wire are also used, but are not our preferred choice. Inflatable splints have potential disadvantages of over inflation (limb ischemia) or under inflation (ineffective immobilization). These splints should not be applied over clothing as this can cause skin injury.

If medical attention has not yet arrived, a splint can be fashioned out of materials commonly found in most homes. An example is the pillow splint (Fig. 1–17A) formed by wrapping an ordinary pillow tightly around a lower-extremity fracture and securing it with safety pins. Alternatively, a splint can be made from towels wrapped around the limb and supported on either side by wood boards (Fig. 1–17B). The same type of splint can be used in the upper extremity with the addition of a sling to support the forearm.

Patients who present with open fractures should be splinted in a similar manner; however, the site of skin injury should be covered with a sterile dressing. One should be careful not to replace any exposed bone fragment back into the wound to avoid further contamination.

Emergency Department Immobilization

A fracture is immobilized in the emergency department to stabilize unstable fractures, relieve pain, and permit healing. The presence of a fracture, however, should not be automatically equated with the need for immobilization (e.g., clavicle fracture). The fundamental rules of splints and casts are identical. Ideally, at least one joint above and below the fracture should be immobilized. In general, the extremity should be placed in the position of function before it is immobilized, although there are exceptions to this rule depending on the injury (Table 1–2).

Splints

Splints differ from casts in that they are not circumferential and allow swelling of the extremity without a significant increase in tissue pressure. Ice packs can be applied closer to the skin in patients immobilized in a splint, thereby maximizing its effect. For these reasons, splints are more frequently used as the initial means of immobilization in the emergency department. Once swelling has decreased, casting is performed because splints permit more motion and provide less stability for a reduced fracture that needs to be maintained in a fixed position.

Splints and casts are strengthened by one of two different materials—plaster or fiberglass. The plaster rolls or slabs used in casting are stiffened by dextrose or starch and impregnated with a hemihydrate of calcium sulfate. When water is added to the calcium sulfate a reaction occurs that liberates heat, which is noted by both the patient and the physician applying the cast.

CaSO₄ + H₂O → H₂O CaSO₄ ∙ H₂O + Heat

Accelerator substances are added to the bandages that allow them to set at differing rates. Common table salt can be used to retard the setting of the plaster, if this is desired, by simply adding salt to the water. Acceleration of the setting occurs by increasing the temperature of the water. The colder the water temperature, the longer the plaster takes to set.

For plaster splints, a stockinette is placed on the extremity with a generous amount allowed at the distal and proximal ends where the splint is to be applied (Fig. 1–18). Next, a soft layer of padding (e.g., Webril) is circumferentially placed around the extremity with special care to provide extra padding to areas where bony protuberances are most prominent (i.e., malleoli, heel). The plaster is measured and cut or torn to the appropriate length. For maximal strength, 8 to 10 layers should be used. The plaster layers are then immersed in warm water, smoothed for additional strength, and applied to the extremity. A strip of cast padding can be applied over the outer surface of the plaster so that the elastic bandage does not adhere. This will aid in the removal of the splint. Finally, an elastic bandage is applied to secure the splint to the limb. It is important to wrap the elastic bandage snug, but not too tightly to avoid causing limb ischemia or a compartment syndrome.

Commercially available fiberglass splint materials, which incorporate the padding and fiberglass in one piece, are readily available. These splints are quick, clean, and easy to use for immobilizing joints following soft-tissue injuries and most stable fractures. The fiberglass is activated with a small amount of water and it dries quickly. Care should be taken to stretch the padding over the cut end of this splint material so that contact with the skin is avoided. Dried fiberglass is sharp and will cause skin irritation and pain. For unstable fractures that require reduction, we recommend plaster splinting because it molds to the limb better.

Casts

Casts are applied in a similar manner to splints. First, stockinette is placed on the extremity so that extra is available on either side of where the cast will be placed. Next, cast padding is applied from the distal to the proximal end of the limb (Fig. 1–19A and B). The cast padding interposed between the skin and the plaster provides elastic pressure and enhances the fixation of the limb by compensating for slight shrinkage of the tissues after application of the cast. Too much padding reduces the efficacy of the cast and permits excessive motion. Generally, the more padding used, the more plaster needed (Video 1–1).

After placing a plaster roll in water, squeeze the ends together to eliminate excess water while retaining the plaster in the roll. The plaster bandage should be rolled in the same direction as the padding, and each turn should overlap the preceding one by 50%. The plaster should always be laid on transversely with the roll of bandage in contact with the surface of the limb almost continuously. The roll should be lightly guided around the limb, and pressure should be applied by the thenar eminence to mold the plaster. Each turn should be smoothed with the thenar eminence of the right hand as the left hand guides the roll around the limb. As the limb tapers, the casting material is made to lie evenly by small tucks made using the index finger and thumb of the right hand before each turn is smoothed into position (Fig. 1–19C). The palms and thenar eminences of the hands smooth the bandage when it is applied. Remember that the durability and strength of the cast depends on welding together each individual layer by the smoothing movements of both hands (Fig. 1–19D). Finally, the stockinette is folded back and the last roll of plaster is applied (Fig. 1–19E).

Some common casting mistakes include the following:

1. Making the center of the cast too thick. One should concentrate on making the two ends of the cast of adequate thickness because it is easy to make the center too thick. This provides no additional support at the fracture site (Fig. 1–20).

2. Using too many narrow bandages, rather than fewer wider rolls, creating a lumpy appearance to the cast. Bandages of widths of 4, 6, and 8 in are most commonly used for casting.

3. Applying the plaster too loosely, especially over the proximal fleshy portion of the limb. A better fit is needed here than at the distal bony parts.

The application of a walking heel should be under the center of the foot (Fig. 1–21). The heel should be centered midway between the posterior tip of the calcaneus and the distal end of the “ball” of the foot. If one needs to reinforce the cast, as in an obese patient with a walking cast, this should be done by adding a fin to the front, not by adding excessive posterior splints to the back, as this only adds weight to the cast and does not make it stronger.

When applying a cast to the upper extremity, the hand should be left free by stopping the cast at the metacarpal heads dorsally and the proximal flexor crease of the palm volarly to permit normal finger motion (Fig. 1–22).

A window may be placed in a cast when a laceration or any skin lesion needs care while treating the fracture. To make a window, cover the wound with a bulky piece of ­sterile gauze and apply the cast over the dressing in the normal manner. Once the cast is complete then cut out the “bulge” created by the gauze dressing (Fig. 1–23). The cast defect should always be covered with a bulky dressing and held firmly in place with an elastic bandage to avoid herniation of the soft tissue and subsequent swelling and skin ulceration.

As mentioned earlier, casts are not used as frequently in the emergency department as splints. Applying a circumferential cast in the acute setting can be problematic due to swelling and may result in a compartment syndrome. If a cast is placed in the emergency department and additional swelling is anticipated, the cast is cut on both sides and wrapped with an elastic bandage to hold it together. This process is known as “bivalving” the cast.

Fiberglass cast material is also used as it is lightweight, strong, and radiolucent.⁷ Fiberglass casts can become wet without being softened or damaged. Fiberglass casts have limited applications to fresh fractures because fiberglass cannot be molded to the limb as well as the plaster. Another disadvantage is that the polyurethane resin within the fiberglass adheres to unprotected skin. Therefore, fiberglass casts are best used as a second or subsequent cast.

Checking Casts

Any patient with a circumferential cast should receive written instructions describing the symptoms of compartment syndrome from a tight cast. Increasing pain, swelling, coolness, or change in skin color of the distal portions of the extremity are signs that a cast is too tight and the patient should be instructed to return immediately. As a general rule, we recommend that any circumferential cast be checked the following day for signs of circulatory compromise. The patient must be instructed to elevate the limb to avoid problems.

If a patient complains of discomfort at any point after cast application, it is best to remove the cast to check for compartment syndrome, pressure sores, or peripheral nerve injury. Alternatively, the cast can be split on both sides (i.e., bivalved) to decrease pressure. If the patient’s complaints persist, the cast should be removed.

Figure 1–24 demonstrates the proper technique for removing or splitting a cast. The oscillating cast saw used to split plaster is generally safe, but can cut skin if not used carefully. One must remember to split not only the plaster casting but also the inner padding to significantly reduce the pressure. This was well demonstrated in a study that showed that no significant reduction in pressure occurred when only the plaster was opened. Splitting the plaster and the padding did result in a significant reduction in the soft-tissue pressure.⁸

Closed Fracture Reduction

Fracture reduction is performed either open via surgery or closed. Closed reduction is carried out in the emergency department or operating room depending on the circumstances. Successful closed reduction is more likely if it is carried out as close to the time of injury as possible. Delaying reduction by several days will make the reduction more difficult.

Closed reduction should occur on an emergent basis when perfusion to the extremity is absent, especially in the setting of limited availability of orthopedic consultation. Because vascular injury can occur after any displaced fracture or dislocation, the clinician should note the presence of an expanding hematoma, absent distal pulses, or delayed capillary refill. A nonperfused extremity has a finite period of time before nerve and muscle death occurs. For this reason, reduction should occur as soon as possible. The earlier the perfusion is regained, the better the chance of avoiding tissue necrosis.

Reduction in the emergency department is contraindicated in several instances:

1. The extremity is perfused and the patient will require immediate operative treatment. An open fracture in a perfused extremity, for example, should be reduced in the operating room where an appropriate surgical washout can occur.

2. Remodeling is anticipated or the fracture will heal adequately without reduction. Remodeling, especially in children, may correct deformities gradually with healing and make the need for a painful reduction or the risk of procedural sedation unnecessary. In the adult skeleton, humeral shaft fractures and fifth metacarpal neck fractures are examples of bones in which some degree of residual angulation will not impact function, making reduction unnecessary.

3. Procedural sedation is inadequate or high risk. If adequate analgesia cannot be provided due to the patient’s medical condition or the inability to appropriately monitor the patient, emergency department reduction should not be performed.

4. Vascular injury may be worsened by closed reduction. When vascular injury is suspected in a patient with a posterior sternoclavicular joint dislocation, for example, reduction is best performed in the operating room with a cardiothoracic surgeon available because the distal clavicle may be tamponading a lacerated subclavian vessel. In a similar manner, supracondylar fractures require immediate reduction only when the extremity is pulseless and perfusion is absent.

The preparation of a patient for fracture reduction is dependent on the type of injury and the clinical setting. Explain the procedure to the patient and obtain consent. In performing the reduction, the patient should be supine whenever possible. The involved extremity should be fully exposed and any constricting pieces of clothing or jewelry both proximal and distal to the injury should be removed. If fluoroscopy is used, it should be moved into position. Frequently, splint material is set up prior to the start of the procedure so that it may be immediately applied to the extremity following reduction. This is especially helpful in the setting of an unstable fracture.

The basic principles to reduce fractures are similar and can be divided into four steps:

1. Distraction

2. Disengagement

3. Reapposition

4. Release

Distraction involves creating a longitudinal force to pull the bony fragments apart. This step is performed gradually and may require time to be effective in overcoming muscle spasm. Distraction is also important when the fractured ends of the bone are overriding. Distraction can be applied manually with the help of an assistant or by using weights.

Disengagement of the bony ends of the fracture allows for further disimpaction of the bone than distraction alone. Disengagement can be achieved by rotating the distal fragment or by “recreating the fracture deformity.” It relieves tension on the soft tissues to allow interlocking fracture fragments to reposition.

Reapposition is achieved by reversing the forces that caused the injury to bring the bone fragments back into alignment. A displaced fracture usually leaves the periosteum intact on one side. Without this intact periosteal bridge, reduction would be difficult to maintain (Fig. 1–25). An intact ­periosteal bridge will assist in the reduction and the maintenance of the reduction. Although this step seems simple conceptually, it may not be so easy in clinical practice. One important pitfall to avoid is ignoring a rotational deformity that might create functional problems if the bone went on to heal in this manner.

Release refers to the removal of the initial distracting force with the intent that alignment will be maintained. At this point, forces such as muscle contraction and gravity act on the fracture fragments putting them at risk for becoming malaligned again. A properly applied splint or cast can protect from loss of fracture alignment. The patient should undergo repeat plain radiography or fluoroscopy in most cases to document the success of the reduction.

Following reduction, the neurovascular status of the extremity should be reassessed to ensure that pulses are present, the extremity is well perfused, and that nerve function has not been compromised.

The astute clinician should also be aware of the limitations of the closed reduction technique. If soft tissue is interposed, for example, the fracture may be irreducible and no amount of distraction or alternative technique will obviate the situation. Additionally, fractures that are more than a week old are more difficult to reduce.

When performed properly, complications of fracture reduction are uncommon. However, even when techniques are properly adhered to, a complication may occur. These complications include converting a closed fracture to an open fracture, soft-tissue trauma during reduction that produces fracture instability or compartment syndrome, or neurovascular injury due to bony laceration or compression.

Definitive Treatment

The selection of definitive fracture treatment is a combined decision between the emergency physician and the referral physician. Some fractures can be treated safely with immobilization alone despite some angulation (e.g., humeral shaft, fifth metacarpal neck fracture). Others require closed reduction when displaced or angulated (e.g., Colles fracture). And still others require consultation for operative intervention (e.g., open fracture, femur fracture).

The management of individual fractures is discussed further in the remainder of the book. The emergency physician must be aware of the indications for operative intervention in managing fractures. Some general indications for operative management include the following:

• Displaced intra-articular fractures

• Associated arterial injury

• Experience shows that open treatment yields better results

• Closed methods fail to achieve or maintain acceptable alignment

• Fracture is through a metastatic lesion

• Early mobilization is desirable

Skeletal Traction

Traction can be applied to the skin (skin traction) or bone (skeletal traction) to align fractures. Skin traction has been used since popularized by Buck in the U.S. Civil War (Fig. 1–26). It has been used as a temporary means to stabilize fractures of the hip; however, it is rarely used today. The use of adhesive tape and weights greater than 6 to 8 lb should be avoided as they may cause an avulsion of the superficial skin layers.

Skeletal traction, applied by an orthopedic consultant, is the preferred form of traction (Fig. 1–27). A pin (e.g., Steinmann pin) is passed through a bony prominence distal to the fracture site and weights are used to pull the fracture fragments into better alignment. This method is especially useful for comminuted fractures that cannot be held by plaster fixation. Skeletal traction may be used as the sole treatment method when surgery is contraindicated, but it is more commonly used today as a temporary measure before a more definitive operative repair (i.e., intramedullary rod).

Skeletal traction is used most frequently in fractures of the femur and also in some tibia fractures, although it can be employed in the upper extremity to align humerus fractures. Common sites for pin placement in the lower extremity include the distal femur, proximal tibia, lower tibia, and calcaneus (Video 1–2). Complications include pin tract infections and overdistraction of the fracture.

Orthopedic Devices

A variety of devices are used to surgically stabilize an unstable fracture (Fig. 1–28). It is important for the emergency physician to have some familiarity with these devices and recognize their potential complications. The most common complications include implant failure (i.e., breakage), loss of fixation, and infections.

Plate and screws place the fracture ends in acceptable alignment to allow healing. If the fracture does not heal spontaneously, the plate will eventually break or the screws will come out. Healing occurs without the callus formation seen with casting. Screws may also be used independent of a plate. Examples include stabilization of a slipped capital femoral epiphysis and a displaced scaphoid fracture. The most common complication of this type of internal fixation is wound infection.

Intramedullary rods (nails) are either rigid or flexible. Rigid intramedullary rods are used to treat long bone fractures. Because the fracture is not held in as much rigid alignment as a plate and screws, callus formation at the fracture site is more pronounced. Fracture healing is usually excellent because the periosteum and fracture hematoma are not disturbed when the rod is placed. Once the rod is placed, interlocking screws are frequently added to provide rotational stability. Flexible intramedullary rods are most common in the pediatric population because they can be inserted through the metaphyseal portion of the bone and avoid injury to the growth plate. Rods are mechanically stronger than a plate and screws, but can break if the fracture does not unite. Infection is less common than with plate and screws. Flexible and unlocked rigid intramedullary rods can migrate out of the bone and into the soft tissues.

Percutaneous pins are used for fractures of the small bones of the hand and foot. As the name implies, the pin is inserted directly through the skin and then can be cut so that only a small portion of the pin is exposed. These stainless steel pins are also frequently referred to as Kirschner wires or K wires after Martin Kirschner who introduced them in 1909. Complications of these devices include pin tract infections, migration, or breakage.

Tension band wires are used to realign fractures that undergo distracting forces because of muscles. Examples include olecranon, greater tuberosity proximal humerus, and patella fractures. In this technique, the fracture fragments are aligned by percutaneous pins that also function as an anchor for a loop of flexible wire that serves to hold the fragments together. Complications of these devices include breakage, bursitis, and wire perforation through the skin.

External fixation has a frame that is supported by pins placed through the proximal and distal fracture fragments. These devices are used preferentially in the setting of open fractures as they allow for monitoring of soft tissues and the reduction of infection. They are also used to temporarily stabilize pelvis fractures and occasionally for the treatment of distal radius fractures. Pin tract infections and loosening of the device are the most common complications.

Prosthetic joints are available for almost every joint in the body. They are considered a total (complete) arthroplasty if both sides of the joint are replaced and a hemiarthroplasty (partial) if only one side of the joint is prosthetic. In the hip, total joint arthroplasty is used more commonly for arthritis, whereas hemiarthroplasty may be all that is required for a displaced femoral neck fracture. The most common type of total hip replacement uses a metal femoral prosthesis that articulates with a plastic acetabular cup. The plastic cup is secured to the acetabulum via a metal backing. The term “constrained” is used when the two portions of the prosthetic joint are locked together instead of being stabilized by the patient’s intrinsic ligaments and tendons. Constrained devices are more likely to loosen. Another complication is dislocation, which can occur with both constrained and nonconstrained prosthetic joints. Reduction of a dislocated constrained device is rarely successful in the emergency department and may cause damage to the device if attempted. The other catastrophic complication of a prosthetic joint is infection. Consultation is advised in all cases of a suspected prosthetic joint infection.

Open Fractures

An open fracture occurs when a break in the skin and soft tissue directly communicates with a fracture and its hematoma. Although the diagnosis is straightforward in most cases, it can be difficult when there is a distance between the fracture fragments and the open wound.

A history should be obtained regarding the mechanism and location of injury. A high-energy farm injury, for example, would suggest a worse prognosis with higher rates of contamination than a low-energy fall on a sidewalk. The clinician must perform a neurovascular examination and immediately reduce the fracture only when associated with absent perfusion to the distal extremity.

Examination of the tissue within and around the wound should be performed, noting any contaminants. There should be no attempt to explore the wound digitally in the emergency department as little information will be provided and an increased risk of infection will result. If a question arises when a small wound is noted on the skin that overlies a fracture, one can safely check the wound with a sterile blunt probe to see whether the bone is touched.

Radiographs may aid in the diagnosis if air is seen within the soft tissues in patients who have suffered a recent injury. If it were still unclear whether the fracture is open, the prudent management would dictate to simply treat it as if it were open and debride the wound in the operating room.

Gustilo and Anderson have classified open fractures by the severity of associated soft-tissue damage and degree of wound contamination. This classification system is used widely and will allow the emergency physician to effectively communicate with an orthopedic consultant (Fig. 1–29).

• Grade I describes an open wound due to a low-energy injury. The wound is <1 cm in length and shows no evidence of contamination.⁹ The fractures in grade I wounds are usually simple, transverse, or short oblique with minimal comminution. A fracture fragment piercing the skin from the inside usually causes these wounds.

• Grade II wounds involve a moderate amount of soft-tissue injury. Some comminution of the fracture and a moderate degree of contamination may be present.¹⁰ Grade II open fractures are characterized by a wound that is >1 cm in length. No soft tissue is stripped from the bone.

• Grade IIIA is a large wound (usually >10 cm). The degree of contamination is high and the amount of soft-tissue injury is severe; however, there is adequate soft-tissue coverage of the bone. Comminution of the associated fracture is usually present.

• Grade IIIB is a large wound (usually >10 cm) with periosteal stripping and exposed bone. In this subclass, the degree of soft-tissue injury is such that reconstructive surgery is often necessary to cover the wound. Massive contamination and a severely comminuted fracture are noted in this subclass.¹⁰

• Grade IIIC is similar to the IIIB injury but is associated with the additional finding of significant arterial injury that requires repair for salvage of the extremity.¹¹

Treatment in the prehospital setting consists of covering the wound with a sterile dressing and splinting the extremity. In the emergency department, foreign bodies or obvious debris should be removed sterilely either manually or with forceps. Tetanus prophylaxis is administered when indicated. Tdap (tetanus, diphtheria, and pertussis) should be administered to adults greater than age 19 once in their lifetime and to pregnant patients during each pregnancy regardless of Tdap interval.¹² The wound can be swabbed for a culture at the request of the orthopedic surgeon; however, there is evidence that predebridement cultures are of little value.¹³

Broad-spectrum antibiotics against both gram-positive and gram-negative organisms are recommended for use in open fractures. Antibiotics should be started as soon as possible after the injury. Delay of more than 3 hours has been shown to increase the rate of infection.¹⁴ The most common organism producing infection is Staphylococcus aureus. The open fracture wound most susceptible to secondary infection is the close-range shotgun wound.

Patients with open fractures should have debridement performed in the operating room. If the patient is to be taken to the operating room for formal irrigation and debridement within 1 to 2 hours of injury, the sterile dressing and splint should be reapplied after obvious debris is removed. If there is a delay in taking the patient to the operating room beyond 2 hours, then the wound should be irrigated with 1 to 2 L of normal saline before the sterile dressing is reapplied. Note that keeping an open wound moist will increase the surface humidity, which is an important factor in healing. In addition, occlusive dressings will facilitate local healing by raising the wound temperature.

Gunshot Wounds

Gunshot wounds are commonplace in our society with as many as 500,000 occurring annually in the United States and 31,672 deaths reported in 2010.¹⁵ Many patients with these injuries present to the emergency department with associated fractures. Weapons are divided into two types—low velocity (<2000 ft/sec) and high velocity (>2000 ft/sec). Wounds inflicted by low-velocity weapons (e.g., handguns and shotguns) are still the most commonly seen; however, wounds from higher-velocity weapons (e.g., M-16, AK-47) are becoming more common. Data show that high-velocity weapons account for 16% of homicides in New York City.¹⁶

Shotguns are low-velocity guns that are different from handguns because they propel hundreds of lead pellets (Fig. 1–30). Because the shotgun has a high efficacy of energy transfer at close range, it causes significant soft-tissue damage and bone injury leading to the highest risk of infection and compartment syndrome. Close-range shotgun blasts can be determined by measuring the diameter of the pellet spread on the patient. A wound with a diameter of <7 cm suggests a close-range shotgun injury.¹⁶

When evaluating a patient with a gunshot wound to the extremity, the clinician must first address the ABCs of trauma care with a thorough primary survey. With regard to the injured extremity, the initial priority is the neurovascular status of the extremity. In patients with signs of vascular injury, angiography and/or intraoperative exploration are warranted.^9,11

Most low-velocity gunshot wounds without evidence of vascular injury can be treated safely with local wound care, tetanus prophylaxis, and outpatient management. Antibiotics are controversial, but most authors recommend routine prophylaxis with a short 3-day course of oral antibiotics (ciprofloxacin, cephalexin, or dicloxacillin).^17–19 Associated fractures are treated according to accepted protocols for similar fractures in patients who were not shot. These injuries are treated as if they were “closed” fractures. Irrigation of the wound is followed by the application of a sterile dressing. The wound is left open and the fracture immobilized appropriately. Patients presenting more than 8 hours after injury may benefit from operative debridement because local wound care is less efficacious.¹⁶

High-velocity injuries, close-range gunshot injuries, and grossly contaminated wounds require operative irrigation and debridement. These wounds are treated as open fractures. Intravenous antibiotics are indicated and should be started prior to surgery.

Gunshot wounds that penetrate a joint generally require arthrotomy or arthroscopy for adequate debridement. The presence of retained bullet fragments within the joint is an absolute indication for operative intervention. These wounds are associated with a high likelihood of injury to the soft tissues of the joint. Low-velocity injuries that penetrated the knee joint had a 42% incidence of meniscal injury and 15% incidence of chondral injury.²⁰ These patients should receive at least 24 to 48 hours of intravenous antibiotics.

An important, yet often omitted, responsibility is careful documentation of the gunshot wound. A simple approach is to record the location of the wound, size or diameter, shape, and characteristics of the wound. Due to the difficulty in accurately determining whether the wound is an entrance or an exit wound do not attempt to describe the wound in these terms.

Another type of injury occurs after the accidental discharge of a nail gun (Fig. 1–31). The majority of injuries occur to the hand. High-velocity nail guns are capable of firing projectiles up to 10 cm into fully stressed concrete, and when discharged accidentally, have caused fatal ­injuries. If important vascular structures are not in proximity and the nail did not enter a joint space, it is safe to remove the nail in the emergency department.

Before removal, however, a radiograph should be obtained. The nails are held together within the gun by copper wires. This is significant because the copper may remain on the nail and create a barb that would make retrograde removal difficult. If such a barb is noted and the nail has pierced through the extremity, the head of the nail should be cut off and the nail pulled the remainder of the way through.²¹

Following removal, the wound is thoroughly irrigated and debrided and the patient is given tetanus prophylaxis as needed (with pertussis if indicated). Most authors recommend a dose of intravenous antibiotics followed by a short course of oral antibiotics.²¹

Stress Fractures

A stress (fatigue) fracture is a common injury seen by health care professionals, particularly those who treat athletes. Under normal conditions of strain, bone hypertrophies. A stress fracture results when repetitive loading of the bone overwhelms the reparative ability of the skeletal system. People in poor physical condition who begin a strenuous fitness program are at a greater risk for developing a stress fracture. Alternatively, a conditioned athlete can develop a stress fracture after a recent increase in activity level. The diagnosis requires a thorough clinical examination with a high index of suspicion.

A number of possible factors may predispose a person to stress fractures. The type of surface (i.e., hard surface) may cause a stress fracture, as could a change in the intensity, speed, or distance at which a patient is doing exercise. ­Inappropriate shoes can result in stress fractures. Other factors include mechanical problems such as a leg length discrepancy, increased knee valgus, foot disorders, and decreased tibial bone width.

The most common sites for stress fractures are listed in Figure 1–32.²² Stress fractures can occur in the upper extremities, but are much less common. Stress fractures are more common in women. Other conditions that should be considered in the differential of stress fractures include periostitis, infection, muscle strain, bursitis, exertional compartment syndrome, and nerve entrapment.²³

The patient presents with a complaint of pain and discomfort, describing an initial aching after exercise that progresses to pain localized to the site of the fracture. In general, the pain starts 4 weeks after the increase in physical activity. Pain progresses in severity during the activity until the exercise is discontinued. The time to diagnosis is variable and may be several weeks to months in some cases.^22,24

The physical examination will vary depending on the location of the stress fracture. A stress fracture of the proximal femur will reveal minimal clinical findings. Pain is usually present in the anterior groin. Hip motion, especially the extremes of internal and external rotation, exacerbates the pain.²³ In addition, pain is produced when the patient is asked to hop on the affected extremity (hop test).²⁴

The initial plain films reveal a fracture in only 10% of cases.²² A bone scan is more sensitive in detecting new stress fractures. It should be noted, however, that a positive bone scan is a nonspecific finding and can occur in other conditions. Other options to confirm the diagnosis when the initial plain films are negative include repeating the plain radiographs, MRI, or CT.

The treatment for stress fractures is conservative unless the location is considered high risk for a completed fracture that may be complicated by nonunion or avascular necrosis. The most common high-risk stress fracture is of the femoral neck. These patients should be treated as if they have an acute fracture and should not bear weight.²³ Operative intervention is often required. Other high-risk stress fractures are the anterior cortex of the tibia, talus, medial malleolus, tarsal navicular, and the fifth metatarsal.

If the stress fracture is not high risk, conservative treatment involves a decrease in activity to the point that the pain is no longer present. It is rarely necessary to eliminate activities of daily living, but if pain is persistent, the patient is kept nonweight bearing. Some authors recommend immediate cross-training, such as bicycling, rollerblading, and pool running.²⁵ Cessation of the precipitating activity for a minimum period of 4 weeks is required. After this period, the patient can gradually resume previous activities. NSAIDs are avoided due to their negative effects on bone healing.²⁶

Pathologic Fractures

A pathologic fracture occurs in bone that is abnormally weakened by a preexisting condition.²⁷ Osteoporosis is the most common cause of a pathologic fracture, followed by metastatic lesions (Fig. 1–33). Table 1–3 lists other causes of pathologic fractures. The most common sites for bony metastasis are the spine, ribs, pelvis, femur, and humerus. Metastatic pathologic fractures rarely occur distal to the knee and elbow. Enchondromas are benign tumors that commonly occur in the metacarpals and phalanges and may lead to fractures.

Any fracture that occurs from trivial trauma must be considered a pathologic fracture. Patients may note generalized bone pain or even painless swelling over the site of the pathologic fracture. Benign lesions are usually asymptomatic prior to the fracture. Bony pain prior to the fracture suggests that the lesion is more likely malignant.

The threshold to obtain plain films should be lower in patients with any of the systemic conditions listed in Table 1–3. On the radiograph, look for generalized osteopenia, periosteal reaction, thinning of the cortices, and changes in the trabecular pattern around the fracture site. The more severe the periosteal lesion, the more likely it is associated with a malignancy. Ultimately, the fracture should be splinted and, depending on the suspicion for malignancy, the patient should be admitted for further diagnostic testing.

Ligamentous Injury

Ligamentous injuries are divided into first-, second-, and third-degree sprains. A first-degree sprain is a tear of only a few fibers and is characterized by minimal swelling, no functional disability, and normal joint motion.

A second-degree sprain is a partial tear of the ligament. Second-degree sprains present with swelling, tenderness, and functional disability; however, there is generally no abnormal motion of the joint noted. Subsequent healing occurs in second-degree sprains, provided the joint is immobilized initially and protected from further mechanical stresses for approximately 6 weeks.

Third-degree sprains are characterized by complete disruption of the ligament and abnormal motion of the joint. Significant swelling occurs shortly after injury, and functional disability is readily apparent. Stress tests perpendicular to the normal plane of joint motion distinguishes second- from third-degree injuries. In patients with third-degree sprains, gross instability without pain is often demonstrated. In contrast, severe pain is caused when a partially damaged ligament is stretched, and the degree of opening of the joint is limited.

In third-degree sprains, direct apposition of the two severed ends of a ligament will result in a better outcome with minimal scar tissue than if the ligament ends have not been sutured. Apposition of the ligament ends hastens collagenization and restores normal ligament tissue. Ligaments divided and not immobilized heal with a gap. Sutured ligaments tested under tension compared to those not sutured showed the sutured ligaments to be stronger. The nonsutured ligaments failed at the scar. For these reasons, the authors would advocate repair of most third-degree (complete) disruptions of major supporting ligaments around weight-bearing joints within the first week after injury.

Bursitis and Tendonitis

Bursae are flattened sacs lined with a synovial membrane and filled with a thin layer of synovial fluid. They function to limit friction created by the movements of tendon and muscle over bony prominences. There are approximately 160 bursae throughout the body. Excessive frictional forces, trauma, or systemic diseases such as rheumatoid arthritis or gout may cause inflammation within a bursa and result in bursitis. The most common form of bursitis is subacromial (subdeltoid) bursitis. Other commonly encountered forms of bursitis include trochanteric, olecranon, calcaneal, anserine, and prepatellar bursitis. Treatment for bursitis consists of avoidance of the aggravating activity, rest of the involved extremity, an NSAID, and local steroid injection.

Tendonitis is an inflammatory process of the tendon involving its insertion into the bone. Tendonitis can result from chronic overuse or a single episode of strenuous activity. Chronic tendonitis results in atrophy of the tendon fibers. Clinically, tendonitis presents with pain during active range of motion and point tenderness near its bony insertion. Forced contraction of the muscle with pressure over the insertion of the tendon exacerbates the pain. Calcific tendonitis is associated with chronic inflammation and calcium deposition within the tendon that can be detected on plain radiographs. Common forms of tendonitis include patellar, quadriceps, rotator cuff, Achilles, lateral epicondylitis (tennis elbow), and de Quervain tenosynovitis. Like bursitis, treatment consists of rest, NSAIDs, and local steroid injection.

Local steroid injection for bursitis and tendonitis requires the physician to be familiar with the anatomy of the affected extremity. If used properly, corticosteroids serve to decrease inflammation, decrease pain, and promote healing. Contraindications to local steroid injection include an overlying cellulitis, suspicion of septic arthritis, coagulopathy, and more than three injections in 1 year.

Corticosteroid preparations available for injection are listed in Table 1–4. Triamcinolone hexacetonide (Aristospan) and triamcinolone acetonide (Kenalog) are preferred as they are potent preparations with long duration of action. The local effects of these agents may last for months. The amount of steroid to be injected depends on the indication. For large spaces such as the subacromial, olecranon, and trochanteric bursae, a dose of 20 to 30 mg of methylprednisolone acetate or its equivalent is appropriate. Tendon sheaths, such as for de Quervain tenosynovitis, require a smaller dose of 5 to 15 mg of methylprednisolone acetate or its equivalent.

The addition of a local anesthetic to the steroid preparation provides two useful purposes. The patient is afforded immediate pain relief and the physician is comfortable that the location of the injection is anatomically correct. Lidocaine, bupivacaine, and mepivacaine are the most commonly used anesthetic agents.

Tendon Rupture

Tendons may be injured by either an avulsion or a laceration. Lacerations occur more commonly than tendon avulsion. Tendon avulsion occurs at the site of bony insertion or the muscle–tendon junction. The four most common avulsed tendons include the Achilles, quadriceps, biceps, and rotator cuff tendons (Fig. 1–34). The peroneal and patellar tendon also commonly rupture. Rupture of the extensor tendons of the hands occurs in patients with rheumatoid arthritis. Medications such as steroids and fluoroquinolones have also been associated with a higher incidence of tendon rupture.^28–30 Achilles tendonitis and rupture are significantly associated with fluoroquinolone use. Age greater than 60, female gender, and body mass index less than 30 kg/m² all increase risk associated with this class of antibiotics.³¹

Tendon avulsions at bony attachments involve a fracture fragment or tendon that can be surgically reattached. Partial tendon ruptures usually heal well if further injury is prevented. Because gaps between the muscle–tendon junctions decrease the strength of the tendon after healing, complete tendon ruptures are repaired surgically. Rupture at the muscle–tendon junction is more difficult to repair surgically than rupture at the site of bony attachment due to the unpredictable nature of suturing tendon to muscle.

The flexor tendons of the hand are the most common tendons to be lacerated. These lacerations pose a unique challenge because the tendons pass through synovial-lined sheaths and fibrous pulleys. Adhesions to these structures, even when the tendon is surgically repaired, limit tendon function and restrict motion. If sutures are too taut, they can constrict the microcirculation of the tendon and impair healing. The commonly used Bunnell crisscross suture technique is particularly invasive.³² Controlled mobilization after tendon repair reduces adhesions and promotes healing, but excessive loading can result in reinjury.

Nerve Injury

Three types of nerve injuries can occur. A simple contusion of a nerve is called a neurapraxia and is treated by observation alone; a return to normal function is noted over the ensuing weeks or months. An axonotmesis is a more significant disruption that is followed by degeneration. The healing time is prolonged. Complete division of a nerve is called a neurotmesis, which typically requires surgical repair.

Muscle Disorders

Muscles are injured by direct and indirect trauma. A forceful blow can cause a localized contusion, hematoma, or laceration of the overlying fascia resulting in herniation. Indirect mechanisms of muscle injury are due to overstretching, and result in tearing of the muscle fibers with ensuing hemorrhage and a partial loss of function—muscle strain. Complications of severe muscle injury are seen early in rhabdomyolysis and late in traumatic myositis ossificans. Muscle injury may also result from a systemic inflammatory response in the form of myositis.

Muscle Contusion

The wounding capacity of an object striking a muscle is directly proportional to its mass and the square of its velocity. Direct blunt trauma to a muscle results in partial disruption of the muscle fibers and capillary rupture. Ecchymosis is seen externally while internally an inflammatory response and edema formation are noted.

Contusions are classified as mild, moderate, and severe. A mild contusion retains normal range of motion and when it occurs in the lower extremity, it does not affect the gait. Localized tenderness is present, but there is no apparent swelling. Moderate contusions are characterized by reduction in range of motion, obvious swelling, and gait disturbance. Severe muscle contusions result in significant reduction in range of motion. Severe tenderness, edema, and an obvious limp are present. If bleeding is severe, a muscular hematoma forms.

Treatment involves restricting range of motion to minimize the risk of hemorrhage. Ice, elevation, and compression are also employed acutely. Restoration of motion occurs gradually as return to activity too early may result in reinjury and a significantly prolonged disability.

Muscle Herniation

Muscle herniates through a defect in the overlying fascia. A soft “tumor” may be palpated through the defect, which is not tethered to the overlying skin. The patient may complain of a swelling or bulge of the muscle when contracted and weakness may be noted. An audible snap associated with severe pain during a strong contraction may be noted. The mass is reduced by compression when the muscle is at rest. The muscles most commonly involved with this condition are the biceps, rectus femoris, and gastrocnemius. The treatment is contingent on the symptoms. If there are significant symptoms, the patient should be referred for repair of the defect.

Muscle Strain

Muscle strain occurs secondary to excessive use (chronic strain) or excessive stress (acute strain). Although a strain can occur at any point within the muscle, the most common location is the distal muscle–tendon junction. Muscles that cross two joints and consist of more fast-twitch fibers (e.g., gastrocnemius, quadriceps, and hamstring) are more susceptible to strains. Strains are divided into first (mild), second (moderate), and third (severe) degree based on the amount of pain, spasm, and disability.

First-Degree Strain

The patient complains of mild localized pain, cramping, or tightness with movement or muscle tension. Pain is frequently not present until after the activity is over. Mild spasm and localized tenderness may be present. Routine function of the muscle is usually preserved with mild limitation. For instance, in the lower extremity, the patient is able to ambulate.

The patient is advised to place ice packs over the injured muscle and to rest for a few days. Mobilization may safely be started as tolerated. The use of an NSAID is indicated in the acute setting.

Second-Degree Strain

More forceful muscle contraction or stretch results in a greater disruption of muscle fibers. Swelling and ecchymosis are frequently present in addition to tenderness and muscle spasm (Fig. 1–35). Pain is immediate in onset in relation to the activity. When the injury is in the lower extremity, it significantly limits ambulation.

In patients with second-degree strains, the injured muscle must be immobilized, the limb elevated, and ice packs applied for the first 24 to 48 hours. After this, the muscle should be “placed at rest” using crutches for ambulation (lower extremity) or a sling (upper extremity) until the swelling and tenderness subsides. Passive stretching should be discouraged when there is significant hemorrhage and swelling as this may result in increased fibrosis, resulting in calcium deposition and a delay in healing. Ambulation (lower extremity) or use of the injured muscle (upper extremity) should not be initiated until the pain has resolved.

After a brief period of immobilization usually lasting no longer than a week, progressive active exercises can be started to the limit of pain.³³ This stage of treatment should be accompanied by heat application. One of the more common complications is recurrence due to early return to normal activity, particularly in the athlete. Calcium deposition in the muscle, leading to prolonged disability, is another common complication, and is also a result of premature return to activity.

Third-Degree Strain

There is complete disruption of the muscle, and the overlying fascia may be ruptured. The patient experiences severe pain and muscle spasm accompanied by swelling and ecchymosis. A large hematoma, localized tenderness, and loss of muscle function are noted, as well as bulging or bunching up of the muscle, particularly if the injury involves the musculotendinous junction.

Third-degree strains should be immobilized in a splint, ice packs applied, and the limb elevated. The patient should be referred for consultation as surgical repair may be indicated depending on age, the location of the tear, and which muscle is involved.

Rhabdomyolysis

This condition occurs when a large enough muscular injury results in the disruption of the integrity of the cell membrane with release of the cellular contents, including myoglobin. Rhabdomyolysis may be a result of crush injury, prolonged immobility, hyperthermia, muscle ischemia, drugs and toxins, infection, and exertion. Muscle pain is present in only 50% of cases. Treatment is supportive and consists of fluid hydration and alkalinization of the urine to prevent myoglobin deposition within the kidney and subsequent renal failure.

Traumatic Myositis Ossificans

Myositis ossificans is a localized muscular ossification that is due to muscle injury in 75% of cases. The formation of bone in muscle can follow a single blow or a series of repeated minor traumas to the muscle. The remainder of cases are seen in paraplegics, burn victims, or may be congenital or idiopathic. The incidence of traumatic myositis ossificans is reported with frequencies of 9% to 17% following muscle contusions.³⁴ The most common muscles affected are the quadriceps and brachialis anticus.³⁵

A hematoma is a necessary prerequisite for the process to occur and this condition is rarely seen after muscle strains. During resorption and organization, the hematoma is invaded by granulation tissue. Collagen proliferates, and osteoblasts, from nearby injured periosteum or from meta-plastic connective tissue, begin to form osteoid trabeculae. It appears that for bone induction to occur in soft tissue, three conditions must be present: (1) an inducing agent, (2) osteogenic precursor cells, and (3) an environment that is permissive to osteogenesis.³⁶

The condition most commonly occurs in patients in their second and third decade of life. The site having the highest predilection for myositis ossificans is the brachialis anticus muscle, anterior to the elbow joint. Injury usually occurs after a posterior dislocation of the elbow. When a mass of bone forms, active and passive motion is restricted. Later, pain and swelling are reduced and a hard, tumor-like mass is palpable over the anterior aspect of the elbow. Active extension of the joint is limited by “inelasticity” of the muscle. Flexion is also prevented by obstruction from the mass. In some cases, there may be a complete ossifying bridge formed at the joint.

Radiographs show the calcified mass beginning by the third to fourth week postinjury, and definite radiographic evidence should be present by 2 months (Fig. 1–36). These lesions must be differentiated from the expanding heterotopic bone formation of an osteosarcoma.³⁵

The mass of bone may be connected to the shaft of a long bone by a pedicle or may be completely separated. Spontaneous repair may occur with complete disappearance of the osseous mass. The process usually ceases spontaneously in 3 to 6 months.

The osseous growth should not be disturbed in its early stage. Prolonged rest is indicated with the extremity immobilized by a splint or lightweight cast. When the elbow is involved, the proper position of immobilization is with the forearm in a neutral position and the elbow flexed to 90 degree. No surgery is indicated for 6 to 12 months because spontaneous resorption can occur with complete disappearance of the mass. Early surgical intervention may result in recurrence of the calcification.

Myositis

Myositis is an inflammation of a muscle that may be due to an infectious agent, such as bacteria, or an autoimmune disorder. For a further discussion of necrotizing soft-tissue infections, the reader is referred to Chapter 4.

Infectious Myositis

Infectious agents that cause myositis include bacteria, mycobacteria, fungi, viruses, and parasitic agents. Bacteria invade muscle by contiguous extension more frequently than hematogenous spread. Acute suppurative myositis with abscess formation in the muscle, pyomyositis, is an unusual, but important condition to consider because it is easily missed. Pyomyositis often presents following muscle trauma (20%–50% of cases) and due to the intramuscular nature of the abscess, many of the superficial findings associated with a soft-tissue infection are absent. Fevers, chills, or an unexplained leukocytosis should help differentiate this condition from other causes of muscle pain. CT scanning may be very useful for detection. Systemic manifestations of sepsis may also occur, but this is usually a later finding.

Pyomyositis is more common in tropical climates and occurs with greater frequency in immunocompromised patients (diabetes, alcoholics, HIV).^37–39 It is usually secondary to spread of infection from an adjacent focus such as an osteomyelitis or a puncture wound. The majority of cases occur in a single muscle or muscle group (quadriceps, gluteus). The most common causative agents are Staphylococcus (75%–95%) and Streptococcus organisms. The treatment includes immediate drainage of the abscess either percutaneously or in the operating room. Intravenous antibiotics should be administered early. Hot moist compresses with elevation of the limb and splinting of the involved extremity are useful adjuncts.

Autoimmune Inflammatory Myositis

Three types of autoimmune inflammatory myositis have been identified—polymyositis, dermatomyositis, and inclusion-body myositis.⁴⁰ Patients present with a varying degree of muscle weakness that develops slowly over weeks to months. Weakness is most severe in the proximal muscles and patients complain of difficulty getting out of a chair, getting in or out of a car, climbing stairs, and combing their hair. Distal muscles and fine motor movements are more commonly affected in inclusion-body myositis. Myalgias are not a common complaint and are present in less than 30% of patients.⁴⁰ In patients with dermatomyositis, a rash precedes the onset of muscle weakness. The rash can be either a purplish color around the eyes or an erythematous, raised rash on the face, neck, chest, back, or joints and may be a marker of skin malignancies.^40,41

Diagnostic features include an increase in creatine kinase levels that is seen in greater than 95% of cases. In active disease, the creatine kinase level can be elevated to 50 times normal. Antibody testing may be helpful, with anti-Jo-1 conferring the greatest specificity. Muscle biopsy is the most important confirmatory test. Treatment includes administration of corticosteroids and immunosuppressive agents. Intravenous immunoglobulin is effective in improving muscle strength and resolving the underlying immunopathology.^40,42