Browse the corpus

CHAPTER 275: Leg Injuries 1859 of soft tissue injury visually and by palpating the compartmental muscle groups. It is often the extent of soft tissue injury, rather than the fracture itself, that determines the outcome. Palpate the knee, and the tibia and fibula along their entire lengths. Palpate the popliteal, dorsal pedal, and posterior tibial pulses. An absent or decreased pulse may indicate the need for urgent fracture reduction and further vascular evaluation. DIAGNOSIS Anteroposterior and lateral radiographs of the leg that include the knee and ankle are sufficient to evaluate bony injuries. If ankle or knee inju ries are suspected, then further imaging is needed. If a tibial shaft frac ture is suspected, splint the leg with a radiolucent device to control pain and prevent further soft tissue damage before obtaining films. Check pulses, movement, and sensation before and after splinting the leg. TREATMENT Cleanse wounds and debride loose tissue and foreign material. Admin ister tetanus immunization as indicated. Splint fractures before obtain ing radiographs; this will prevent further damage to soft tissue caused by movement of bone fragments. Irrigate open wounds and administer parenteral antibiotics (such as cefazolin, 1 gram IV) for open fractures. If compartment syndrome is suspected, measure compartment pressure (see Chapter 278, “Compartment Syndromes”). Treatment of compartment syndrome is fasciotomy of the involved compartment. COMPLICATIONS Wounds that are not adequately cleansed and debrided are prone to infection. Patients with compartment syndromes may develop perma nent disability if elevated tissue pressures are not suspected or diagnosed in a timely fashion. Fractures that are not adequately aligned or immobilized heal poorly or not at all.  SPECIFIC INJURIES TIBIAL SHAFT FRACTURES The tibia is the most commonly fractured long bone. Fractures often result in open injuries because of the minimal amount of subcutaneous tissue between the tibia and the skin. The fracture pattern seen on radiographs will give a clue to the force that caused the injury. Transverse shaft fractures typically result from a direct blow to the bone. Spiral fractures are the result of rotational forces. A comminuted fracture suggests the mechanism had a very high-energy impact. A force powerful enough to shatter the dense cortex of the tibial shaft will often be trans mitted through the interosseous membrane to the fibula, fracturing that bone as well. A major determinant of treatment type and expected outcome is the amount of energy that caused the fracture. High-energy injuries can be predicted somewhat by the history (i.e., low-energy boot-top ski Tibia Interosseous membrane Intermuscular septum Anterior crural septum Posterior crural septum Fibula Anterior compartment Superficial posterior compartment Deep posterior compartment Lateral compartment FIGURE 275-1. Lower leg anatomy. TABLE 275-1 Lower Leg Anatomy Compartments Anterior Lateral Superficial Posterior Deep Posterior Muscles Dorsiflex foot and ankle Plantarflex and evert foot Flex knee and ankle Plantarflex toes, inversion of foot Nerve Deep peroneal Superficial peroneal Sural Posterior tibial Sensation First dorsal web space Dorsum of foot Lateral aspect of foot and distal calf Sole of foot Artery Anterior tibial — — Posterior tibial Leg Injuries Andrea K. Weiers Paul Haller ANATOMY  BONE The tibia provides primary support for weight bearing.

Nerve Deep peroneal Superficial peroneal Sural Posterior tibial Sensation First dorsal web space Dorsum of foot Lateral aspect of foot and distal calf Sole of foot Artery Anterior tibial — — Posterior tibial Leg Injuries Andrea K. Weiers Paul Haller ANATOMY  BONE The tibia provides primary support for weight bearing. The tibia has a thick cortex, and significant force is required to fracture it. Proximally, the tibia splays out to form the medial and lateral plateaus that articulate with the femoral condyles. The lateral plateau is higher and smaller than the medial and is more susceptible to fracture. The distal tibia articulates with the fibula laterally and the talus inferiorly. A dense interosseous membrane connects the tibia and fibula. The distal tibial articulation is supported by the ankle syndesmosis, a series of ligaments inferior to the interosseous membrane. The fibula has a small diameter and lies lateral and posterior to the tibia. It bears little weight but is more easily fractured than the tibia.  COMPARTMENTS The lower leg is divided into four compartments, each coursing parallel to the tibia (Figure 275-1). The compartments are enclosed by nonexpandable bones and connective tissue that limit the compartment size and prevent compartment expansion if its volume increases. Each compartment contains muscles and nerves that may sustain permanent damage with elevated tissue compartment pressure ( Table 275-1). (See also Chapter 278, “Compartment Syndromes. ”) A cross-section at the midcalf level shows the anterior compart ment enclosed by the tibia, interosseous membrane, and anterior crural septum (Table 275-1 and Figure 275-1). Muscles in the anterior com partment group dorsiflex the foot and ankle. The deep peroneal nerve courses within the anterior compartment and exits to provide sensation to the dorsal web space between the first and second toes. The lateral compartment is bordered by the anterior crural septum, the fibula, and the posterior crural septum. Its muscles plantarflex and evert the foot. The superficial peroneal nerve in this compartment pro vides sensation to the dorsum of the foot. The superficial posterior compartment contains muscles that flex the knee and the tibiotalar joints. Its sural nerve provides sensation for the lateral aspect of the foot and the distal calf. The muscles of the deep posterior compartment plantarflex the foot and toes and invert the foot. The posterior tibial nerve that exits this compartment provides sensation to the sole of the foot. CLINICAL FEATURES The history may give clues about the mechanism of injury and atrau matic soft tissue injuries. Evaluate the nerves by checking sensation in the web space, lateral heel, and sole of the foot. Plantarflex and dorsiflex the foot, and evert the foot to test motor function. Evaluate the extent CHAPTER Tintinalli_Sec22_p1767-1880.indd 1859 8/2/19 6:21 PM

ut the mechanism of injury and atrau matic soft tissue injuries. Evaluate the nerves by checking sensation in the web space, lateral heel, and sole of the foot. Plantarflex and dorsiflex the foot, and evert the foot to test motor function. Evaluate the extent CHAPTER Tintinalli_Sec22_p1767-1880.indd 1859 8/2/19 6:21 PM 1860 SECTION 22: Orthopedics injury vs. high-energy motorcycle collision). The amount of energy involved can also be revealed by the fracture pattern on the radiograph. Low-energy accidents often result in transverse or oblique fracture lines, whereas a highenergy accident may cause a comminuted fracture. On physical exam, the amount of damage to the skin and soft tissue is important. Table 275-2 reviews the pattern of injury found in open fractures of the tibia. This system is used to optimize management. A type I open fracture describes a break in the skin that is less than 1 cm in length. A type II open fracture has a laceration that is 1 to 10 cm in length without extensive soft tissue damage, flaps, or avulsions. The fracture pattern here shows simple transverse fractures or short oblique fractures with minimal comminution. Type III injuries are further subdivided into three subtypes. Type IIIA involves segmental fractures or severely comminuted fracture fragments. Type IIIB injuries demonstrate extensive soft tissue loss with periosteal stripping and bony exposure. A type IIIC injury has extensive fracture with major arterial injury requiring repair. The initial management of tibial fractures involves administration of analgesics. Promptly splint the leg with radiolucent material to avoid further soft tissue injury from the movement of the bony fragments. Assess for possible compartment syndrome. Some closed injuries may be treated simply by casting if reduction is able to achieve adequate alignment. Parameters for acceptable reduction include 50% or more of cortical contact, <10 to 15 degrees of angulation on the lateral film, <10 degrees of angulation on the anteroposterior film, and <5 degrees of rotational deformity. 2 Injuries with significant edema and spiral frac tures often require surgical fixation. An intact fibula may make obtain ing or maintaining reduction of the tibial fracture more difficult. A long leg splint from high above the knee with the knee at 5 degrees of flexion and the foot in slight plantarflexion can be applied. Tight-fitting splints or casts may increase the risk of compartment syndrome. Injuries amenable to casting often heal in 4 to 5 months. Patients who can be discharged home after splinting include those who suffered low-energy injuries, have their pain well controlled, and are not at risk of compartment syndrome. The patient with an open tibial fracture requires orthopedic consultation. Injuries with type I soft tissue damage may be cleaned in the operating room and medullary nails inserted to maintain reduction. Those with more extensive injuries may require external fixation or medullary nailing after debridement in the operating room. REDUCTION OF CLOSED TIBIAL SHAFT FRACTURES With many tibial shaft fractures, the break extends through the entire cortex of the bone, but the periosteum is intact on one side of the frac ture. Use of this sturdy periosteal tether can aid in reduction of the fracture. One method of immobilization of long bone fractures incorporates the presence of this intact periosteal hinge and the use of three points of pressure on the shaft of the bone. One focus of pressure is at the site of the fracture, with the pressure being applied from the side opposite the intact periosteum ( Figure 275-2). Two additional sites of pressure are applied, one at the proximal tibia and the other at the distal end of the tibia.

of three points of pressure on the shaft of the bone. One focus of pressure is at the site of the fracture, with the pressure being applied from the side opposite the intact periosteum ( Figure 275-2). Two additional sites of pressure are applied, one at the proximal tibia and the other at the distal end of the tibia. These two forces are applied from the opposite direction of the pressure at the fracture site. This three-point immobilization technique does not always succeed in maintaining the reduction. If the fracture site is near the proximal or distal ends of the tibial shaft, it may be difficult to mold a splint or cast that can effectively transmit the forces needed. Obesity may make molding difficult. If there is a significant amount of swelling already present, or if edema is anticipated in the next several days, then a cast should not be placed as it may result in elevated pres sures in the soft tissue and subsequent compartment syndrome. In these settings, splints should be used with elastic bandages that are able to accommodate the increased swelling. A cast can later be placed in the office of the orthopedist. There are several fractures that may require operative treatment. Open fractures that have concomitant soft tissue damage and swelling can be difficult to adequately control in a cast. In addition, continued care of the soft tissue injury may require multiple cast or splint changes. A second indication for surgical intervention is an inability to obtain or maintain adequate reduction with a closed technique. Many ortho pedists use the following parameters as a guide for adequate reduc tion: (1) >50% abutment of the fractured complex; (2) angulation of <5 degrees on the anteroposterior film; and (3) <5 degrees of rotation of the distal tibia in comparison to the proximal fragment. The presence of an intact fibula may be an indication for operative fixation. When the fibula is intact, it often leads to bowing of the tibia into a varus or valgus position. PILON FRACTURES Pilon is a French word for pestle, a tool used to grind substance in a mortar. In the lower leg, an axial force on the foot can drive the talus into the articular surface of the tibia, grinding or crushing the distal tibia. This injury is also called a tibial plafond fracture (Figure 275-3). FIGURE 275-2. Periosteal hinge. TABLE 275-2 Gustilo Classification of Open Tibia Shaft Fractures Gustilo Grade I II IIIA IIIB IIIC Energy Low Moderate High High High Wound size <1 cm >1 cm Often large zone of injury Often large zone of injury Often large zone of injury Soft tissue damage None None Extensive Extensive Extensive Contamination Clean Moderate Extensive Extensive Extensive Fracture pattern Simple fracture pattern with minimal comminution Moderate comminution Severe comminution or segmental fractures Severe comminution or segmental fractures Severe comminution or segmental fractures Periosteal stripping No No Yes Yes Yes Skin coverage Local coverage Local coverage Local coverage Requires replacement of exposed bone with a free flap for coverage Local coverage Neurovascular injury Normal Normal Normal Normal Exposed fracture with arterial damage that requires repair Tintinalli_Sec22_p1767-1880.indd 1860 8/2/19 6:21 PM

No No Yes Yes Yes Skin coverage Local coverage Local coverage Local coverage Requires replacement of exposed bone with a free flap for coverage Local coverage Neurovascular injury Normal Normal Normal Normal Exposed fracture with arterial damage that requires repair Tintinalli_Sec22_p1767-1880.indd 1860 8/2/19 6:21 PM CHAPTER 275: Leg Injuries 1861 The amount of energy involved in the accident often predicts the type of injury and is important in planning treatment. A high-energy mechanism (motor vehicle crash) often results in significant soft tissue damage with extensive fragmentation of the bone. By contrast, low-energy injuries (skiing) have minimal surrounding soft tissue damage and less comminution of the bone. Radiographs may show at least one fracture plane that extends proximally from the articular surface of the ankle. There are often several fracture planes present. Obtain a CT scan while the leg is in a splint or cast. The scan will help determine the direction of the fracture planes, reveal the amount of articular surface displacement that exists, and aid in the development of a treatment plan. Pilon fractures may be accompanied by compartment syndrome or by vertebral body fractures, particularly a fracture of the first lumbar vertebrae (L1). The goal of treatment is reduction of the fracture fragment and opti mal alignment of the articular surfaces. The extent of soft tissue damage may determine when surgical repair occurs. In the setting of significant soft tissue damage, an external fixation device may temporarily be used to allow this tissue time to heal before definitive surgery. PROXIMAL FIBULA FRACTURE (MAISONNEUVE FRACTURE) Maisonneuve fracture results from an external rotation force applied to the foot. This creates a plane of injury that starts at the medial ankle as either a deltoid ligament rupture or a medial malleolus injury. The injury is then directed upward and laterally, tearing the interosseous membrane that tethers the distal tibia to the fibula. The third component of this injury is a fracture of the proximal fibula. The word proximal is relative; the fibula may be fractured at its head or as far down as 6 cm above the ankle joint (a Weber C ankle fracture). The surgical treatment for this injury is to reduce and stabilize the fractured medial malleolus and to secure the fibula to the distal tibia, allowing the ruptured interosseous membrane to heal. MIDSHAFT FIBULA FRACTURES The shaft of the fibula is most often fractured by a force that has also fractured the tibia; in these cases, treatment is directed by the tibial injury. A direct blow to the fibula can result in an isolated injury to this bone. The patient typically presents with pain or tenderness over the fracture site. With the tibia intact, the patient is often able to bear weight and should be treated with a short leg cast and crutches. Patients with less intense pain may be immobilized with a knee immobilizer (proximal fibula) or elastic wrap (distal fibula) and directed to bear weight as tolerated. STRESS FRACTURE Stress fracture occurs when there is increased muscle activity on bones that are not able to tolerate the additional forces. Extrinsic causes may include a recent increase in activity, running over hard surfaces, or excessive wear on the athlete’s shoes. Adolescent female athletes with eating disorders and military recruits are at high risk for stress fractures. As our population ages, the elderly are taking up activities that may result in stress fractures. The prototypical patient is the Caucasian woman with demineralized bone. Stress fractures are twice as common in women compared with men. About half of stress fractures in athletes occur in the tibia. Less common sites are the tarsals and fibula. Stress fractures may be bilateral.

s that may result in stress fractures. The prototypical patient is the Caucasian woman with demineralized bone. Stress fractures are twice as common in women compared with men. About half of stress fractures in athletes occur in the tibia. Less common sites are the tarsals and fibula. Stress fractures may be bilateral. In adolescents, the site is often the proximal third of the tibia. Runners typically sustain fractures at the junction of the middle and distal third of the tibia. The distal fibula is another common site. The history typically involves a change in the patient’s training pat tern. In an early stage of stress fracture, the patient notices activityinduced pain that is relieved by rest. This can progress to constant pain. On examination, there is pain on palpation over the fracture site, and there may be edema. The pain may be intensified by load bearing on the affected bone. The radiographs of the site are often normal on initial presentation. They may reveal the fracture, which can have the appearance of scle rosed areas oriented linearly. Radiographs obtained 10 to 15 days later may show periosteal elevation or demineralization at the fracture line. Plain films that are initially normal do not exclude the diagnosis. More sensitive tests for stress fracture are the bone scan and MRI. Although these studies are typically ordered at follow-up and not in the ED set ting, they can demonstrate the severity of the change and can be used to predict time to recovery. Treatment of a suspected stress fracture includes discontinuation of the activity. A cast can be applied if significant pain continues. It is not unusual to have pain lasting up to a year despite treatment. ACHILLES TENDON RUPTURE The Achilles tendon is the largest and strongest tendon in the human body. The gastrocnemius and soleus muscles of the calf have tendinous complexes that coalesce to the Achilles tendon that extends about 15 cm to where it inserts on the calcaneus. Its vascular supply is the weakest in the area 2 to 6 cm above the calcaneus, and this is the area that is most frequently ruptured. A typical patient is a 30- to 50-year-old man who participates in strenuous activities on an occasional basis (“weekend warrior”). Risk factors for rupture include older age, prior fluoroquinolone use, and prior steroid injection. The injury often occurs when eccentric force is suddenly applied to a dorsiflexed foot. The patient suffers sudden severe pain and is unable to run, stand on toes, or climb stairs. The most notable finding on examination is a palpable gap in the Achilles tendon 2 to 6 cm proximal to the calcaneus. The calf may be swollen. The patient will be unable to stand on toes. The Thompson test (see Figure 276-8 in Chapter 276, “ Ankle Injuries”) will help dem onstrate the tendon rupture. The patient lies prone with the knee bent at 90 degrees. The examiner squeezes the calf: an intact Achilles tendon will transmit this force to the foot, resulting in its plantarflexion. If the Achilles tendon is ruptured, the foot will not plantarflex when the calf FIGURE 275-3. Plafond fracture. Tibial plafond fracture (pilon fracture) due to an axial compression force. [Reproduced with permission from Simon RR, Sherman SC, Koenigsknecht SJ: Emergency Orthopedics: The Extremities , 5th ed. © The McGraw-Hill Companies. All rights reserved. Part III: Lower Extremities, Chapter 17 Ankle, Fractures, Axial Compression, Imaging, Figure 17-24.] Tintinalli_Sec22_p1767-1880.indd 1861 8/2/19 6:21 PM