XII Международная студенческая научная конференция Студенческий научный форум - 2020

INTRODUCTION

Lower leg fractures include fractures of the tibia and fibula. Of these two bones, the tibia is the only weight bearing bone. Fractures of the tibia generally are associated with fibula fracture, because the force is transmitted along the interosseous membrane to the fibula.

The skin and subcutaneous tissue are very thin over the anterior and medial tibia and as a result of this, a significant number of fractures to the lower leg are open. Even in closed fractures, the thin, soft tissue can become compromised. In contrast, the fibula is well covered by soft tissue over most of its course with the exception of the lateral malleolus.

The tibia and fibula articulate at the proximal tibia-fibular syndesmosis.

Fractures of the tibia can involve the tibial plateau, tibial tubercle, tibial eminence, proximal tibia, tibial shaft, and tibial plafond.

Frequency:

Fractures of the tibia are the most common long bone fractures. Isolated midshaft or proximal fibula fractures are uncommon.

Mortality/Morbidity:

• Limb loss may occur because of severe soft-tissue trauma, neurovascular compromise, popliteal artery injury, compartment syndrome, or infection such as gangrene or osteomyelitis. Popliteal artery injury is a particularly serious injury that threatens the limb and is easily overlooked.

• The common peroneal nerve crosses the fibular neck. This nerve is susceptible to injury from a fibular neck fracture, the pressure of a splint, or during surgical repair. This can result in foot drop and sensation abnormalities.

• Delayed union, nonunion, and arthritis may occur. Among the long bones, the tibia is the most common site of fracture nonunion.

Age: Toddler fracture (distal spiral fracture of the tibia) is most common in children aged 9 months to 3 years.

History:

• Patient may report a history of direct (motor vehicle crash or axial loading) or indirect (twisting) trauma.

• Patient may complain of pain, swelling, and inability to ambulate with tibia fracture.

• Ambulation is possible with isolated fibula fracture.

• Tibial plateau fractures occur from axial loading with valgus or varus forces, such as in a fall from a height or collision with the bumper of a car. The lateral tibial plateau is fractured more frequently than the medial plateau.

• Tibial tubercle fractures usually occur during jumping activities such as basketball, diving, football, and gymnastics. This type of fracture is more common in adolescents than in adults.

• Tibial eminence fractures occur with trauma to the distal femur while the knee is flexed such as falling off of a bicycle. Another mechanism for this fracture is hyperextension.

• Tibial shaft fractures usually present with a history of major trauma. An exception to this is a toddler's fracture, which is a spiral fracture that occurs with minor trauma in children who are learning to walk.

• Tibial plafond fractures refer to fractures involving the weight-bearing surface of the distal tibia. This type of injury usually results from high-energy axial loading but may result from lower-energy rotation forces.

• Maisonneuve fractures are rare and considered unstable ankle injuries. This type of injury usually involves a pronation-external rotation force.

Physical:

• Tibial plateau fractures often present with a knee effusion. Tenderness will be present along the medial or lateral tibial plateau. Approximately 20% of tibial plateau fractures are associated with ligamentous injuries.

• Tibial tubercle fracture will have tenderness over the anterior tibia approximately 3 cm distal to the articular surface. In more severe tibial tubercle fractures, full extension of the knee is not possible. The patella may be high riding.

• Tibial eminence fracture may present with a knee effusion and pain and may represent an avulsion of the tibial attachment of the anterior cruciate ligament.

• Tibial shaft fractures are the most common long bone fracture and usually involve the fibula as well. Tibial fractures present with localized pain, swelling, and deformity.

• Maisonneuve fractures involve a fracture of the proximal fibula in association with a fractured medial malleolus (or injured deltoid ligament) and diastasis of the distal tibiofibular syndesmosis. Patients present with proximal fibular pain in addition to medial ankle pain. This is an unstable ankle injury.

• Tibial plafond fractures will have tenderness along the distal tibial and may have severely decreased range of motion in the ankle.

Causes:

• Direct forces such as those caused by falls and MVCs.

• Indirect or rotational forces.

CLASSIFICATION

FRACTURE OF PROXIMAL PART OF TIBIA

Extra articular/intra articular

Simple/complex

Unicondylar/bicondylar

FRACTURE OF DIAPHSEAL PART OF TIBIA

Simple/wedge/complex

Upper/middle/lower

FRACTURE OF DISTAL PART OF TIBIA

Condylar/malleolar

Simple/complex

FRACTURE CLASSIFICATION (SCHATZKER)

Type I— pure cleavage. A typical wedge-shaped uncomminuted fragment is split off and displaced laterally and downward. This fracture is common in younger patients without osteoporotic bone. If displaced, it can be fixed with two transverse cancellous screws.

Type II— cleavage combined with depression .lateral wedge is split off, but in addition the articular surface is depressed down into the metaphysis. This tends to occur in older people, and, if the depression is more than 5 to 8 mm or instability is present, most should be treated by open reduction, elevation of the depressed plateau "en mass," bone grafting of the metaphysis, fixation of the fracture with cancellous screws, and buttress plating of the lateral cortex.

Type III— pure central depression. The articular surface is driven into the plateau. The lateral cortex is intact. These tend to occur in osteoporotic bone. If the depression is severe or if instability can be demonstrated on stress, the articular fragments should be elevated and bone-grafted, and the lateral cortex is supported with a buttress plate.

Type IV— fractures of medial condyle. These may be split off as a single wedge or may be comminuted and depressed. The tibial spines often are involved. These fractures tend to angulate into varus and should be treated by open reduction and fixation with a medial buttress plate and cancellous screws.

Type VI— plateau fracture with dissociation of metaphysis and diaphysis. A transverse or oblique fracture of the proximal tibia is present in addition to a fracture of one or both tibial condyles and articular surfaces. The dissociation of the diaphysis and metaphysis makes this fracture unsuitable for treatment in traction, and most should be treated with buttress plates and cancellous screws, one on either side if both condyles are fractured. More recently, pin and wire fixators have been advocated for fixation of these difficult fractures.

FRACTURE-DISLOCATION CLASSIFICATION (HOHL AND MOORE)

The fracture-dislocation patterns classified by Hohl and Moore, in addition to occurring with a higher incidence of associated ligamentous injuries, occur with more frequent meniscal injuries, which usually are not reparable, and a much higher incidence of neurovascular injury, increasing from 2% for type I to 50% for type V, with an overall average of 15%, approximately that of classic dislocation of the knee.

Type I— coronal split fracture. Originally Hohl type 5 fractures, these account for 37% of tibial plateau fracture-dislocations. The fracture involves the medial side, is apparent on the lateral view, and has a fracture line running at 45 degrees to the medial plateau in an oblique coronal-transverse plane.

Type II— entire condyle fracture. This fracture-dislocation may involve the medial or lateral plateau and is distinguished from the type IV fracture by a fracture line extending into the opposite compartment beneath the intercondylar eminence.

Type III— rim avulsion fracture. Constituting 16% of fracture-dislocations, this type involves almost exclusively the lateral plateau, with avulsion fragments of the capsular attachment, tubercle of Gerdy, or the plateau.

Type IV— rim compression fracture. This injury accounts for 12% of all fracture-dislocations. It almost is always unstable. The opposite collateral ligament complex and usually (75% of patients) the cruciate ligaments are avulsed or torn, allowing the tibia to sublux to the extent that the femoral condyle compresses a portion of the anterior, posterior, or "middle" articular rim. Stable injuries can be treated by casting until the ligaments heal.

Type V— four-part fracture. Constituting 10% of all fracture dislocations, this injury is nearly always unstable. Neurovascular injury occurs in 50% of fractures; the popliteal artery and the peroneal nerve are both injured in over one third. Both collateral ligament complexes are disrupted with the bicondylar fracture, and the stabilization provided by the cruciates is lost because the intercondylar eminence is a separate fragment.

RUPTURE AND DISLOCATION

Dislocation of superior and inferior tibia fibular joint, fracture too can occur. Leg dislocation is a lot possible at knee joint anteriorly and posteriorly.

LEG DISLOCATION

Mechanism – forced hyperflextion, lesion of all main ligaments.

Clinical - severe pain, loss of standing/walking position, and deformity.

Hospital treatment – close deduction is necessary. Stiffness of knee is seen.

Tibial Plateau Fracture

Proximal tibial articular fractures caused by high-energy mechanisms may be associated with neurological and vascular injury, compartment syndrome, deep vein thrombosis, and contusion or crush injury to the soft tissues, or open wounds. Complex fractures involving both the femoral and tibial articular surfaces had a 25% incidence of vascular injury and 25% incidence of compartment syndrome. In 19 complex fractures with severe soft tissue injury, vascular injury occurred in 31%, compartment syndrome in 31%, and peroneal nerve injury in 23%. Accurate determination of fracture pattern, as well as soft tissue injury, is necessary when developing a treatment plan.

Proximal tibial articular fractures can be caused by motor vehicle accidents or bumper strike injuries; however, sports injuries, falls, and other less violent trauma frequently produce them, especially in elderly patients with osteopenia.

EVALUATION

A thorough history should be obtained, including determination of the mechanism of injury and the patient's overall medical status, age, and functional and economic demands.

Anteroposterior, lateral and oblique roentgenograms and CT are necessary to evaluate these fractures. Assessment of the degree and the size of depressed articular fragments may be possible only with conventional or computed axial tomography. Often the classification of the fracture made from standard roentgenograms is changed to another type after tomograms are evaluated. The upper tibial articular surface normally is inclined posteriorly 10 to 15 degrees, and an anteroposterior roentgenogram with the beam angled caudally 10 to 15 degrees provides better views of the tibial plateaus.

TREATMENT

Goals of treatment of proximal tibial articular fractures include restoration of articular congruity, axial alignment, joint stability, and functional motion. If operative treatment is chosen, fixation must be stable enough to allow early motion, and the operative technique should minimize wound complications. Surgical treatment usually is recommended for fractures associated with instability, ligamentous injury, and significant articular displacement; open fractures; and fractures associated with compartment syndrome. After the articular surfaces of a joint have been fractured, joint function usually is proportionate to the accuracy of reduction. For displaced fractures, most authors point out that the most significant factor influencing long-term results, and hence treatment approach, is the degree of displacement and depression. The degree of acceptable articular displacement is a matter of controversy. Brown et al. showed that an articular step-off of 3 mm caused a significant increase in articular cartilage contact pressures in an experimental model of split fractures.

Treatment methods proposed for fractures of the tibial condyles include extensile exposure with arthrotomy and reconstruction of the joint surface with plate and screw fixation, arthroscopy or limited arthrotomy and percutaneous screw fixation or external fixation with pin or wire fixators, closed manipulation and casting, especially with a cast brace, and traction with early motion. Newer plating techniques are done with less soft tissue stripping than older techniques and usually use smaller incisions. If more than one incision is used, a large soft tissue bridge is left between them. No method can be used routinely for all fractures, and each patient must be individually evaluated. Extensive surgery on a severely comminuted fracture may result in less than optimal internal fixation and a need for postoperative immobilization, often resulting in the joint being neither stable nor freely movable. The use of traction for tibial condylar fractures usually produces good early motion, but significant residual deformities and instability often lead to degenerative changes or arthritis.

FRACTURE OF LATERAL CONDYLE

This fracture usually is produced by a valgus strain on the knee, with the ligaments and muscles on the medial side resisting separation of the tibial and femoral condyles. The lateral femoral condyle is driven downward into the weight-bearing surface of the lateral tibial condyle, depressing the central portion of the articular surface into the cancellous metaphysis well below its normal level. In addition, the lateral margin of the articular surface of the tibia bursts laterally, and one or more fractures extend longitudinally down into the metaphysis of the tibia, producing a lateral fragment. This fragment usually is large and, when seen from the lateral side, often is triangular with the base of the triangle proximal. Usually the fragment is held at joint level by the intact fibula. Less often, the lateral condyle fractures the fibula at its neck and may be displaced as one large fragment with only slight central depression and comminution.

Open treatment of tibial plateau fractures is made easier by the use of the AO femoral distractor. For lateral plateau fractures, one bicortical pin is inserted just anterior to the lateral femoral epicondyle, parallel to the joint. The second pin is inserted into the lateral tibial cortex, distal to the site of proposed fixation, in the midcoronal plane, perpendicular to the tibia. As the distractor is lengthened, much of the reduction is attained by ligamentotaxis. Because the femoral pin is located near the center of rotation of the femoral condyle, the fracture is minimally disturbed by flexion and extension of the knee in attempts to locate the fracture lines and fix the plateau. If care is taken not to over distract the soft tissue, the femoral distractor is a tireless assistant.

AFTER TREATMENT: The knee is placed in a posterior plaster splint. At 3 to 4 days, if the wound is healing satisfactorily, the splint is removed, and physical therapy with quadriceps exercises and gentle active-assisted exercises are begun, or a passive motion machine can be used. Crutch walking is begun, but no weight bearing is permitted for 12 to 16 weeks. If extensive suturing of the periphery of the meniscus has been required, immobilization for approximately 3 weeks is required before motion exercises are permitted.

ARTHROSCOPICALLY ASSISTED REDUCTION AND FIXATION OF TIBIAL PLATEAU FRACTURES

Arthroscopically assisted reduction and fixation techniques are being used with increased frequency for the treatment of Schatzker types II, III tibial plateau fractures, and I. Arthroscopic techniques require minimal soft tissue dissection, afford excellent exposure of the articular surface, and can be used to diagnose and treat concomitant meniscal injury.

FRACTURE OF MEDIAL CONDYLE

If open reduction, elevation, and internal fixation of the medial tibial condyle are required, a technique similar to that previously described for the lateral tibial condyle is carried out. The fracture can be approached through a straight anterior or anteromedial incision. For split compression and total depression fractures of the medial tibial condyle, in addition to elevating the depressed fragment and packing bone beneath it, an AO plate can be used as a medial buttressing plate. This can be bent to an accurate contour to fit the tibial metaphysis and the tibial condyle, and the fracture can be fixed with cancellous screws in the proximal portion of the plate and regular cortical screws in the distal portion.

OPEN REDUCTION AND INTERNAL FIXATION

The surgical approach to complex tibial plateau fractures must be individualized on the basis of particular fracture configuration. The following is a general approach applicable to many of these fractures.

AFTERTREATMENT: After 3 or 4 days, if the wound is healing satisfactorily, the knee is brought into full extension and gentle active and active-assisted exercises are begun. At 3 weeks, as the knee motion gradually improves, the patient is placed in a femoral cast brace, but no weight bearing is allowed for 10 to 12 weeks.

TIBIAL SHAFT

Open fractures are more common in the tibia than in any other major long bone. Furthermore, the blood supply to the tibia is more precarious than that of bones enclosed by heavy muscles. High-energy tibial fractures may be associated with compartment syndrome or neural or vascular injury. The presence of hinge joints at the knee and the ankle allows no adjustment for rotary deformity after fracture, and thus special care is necessary during reduction to correct such deformity. Delayed union, nonunion, and infection are relatively common complications of tibial shaft fractures

Fractures in which closed treatment is not appropriate can be treated with plate and screw fixation, intramedullary fixation (including Ender pins, intramedullary nails, and interlocking intramedullary nails), and external fixation. Locked intramedullary nailing currently is the preferred treatment for most tibial shaft fractures requiring operative fixation. Plating is used primarily for fractures at or proximal to the metaphyseal-diaphyseal junction. External fixation is useful for fractures with periarticular extension and for severe open fractures. In severely mangled extremities, amputation should be considered.

FRACTURES OF PROXIMAL THIRD OF TIBIAL SHAFT

The enthusiasm for locked nailing of tibial shaft fractures has led some surgeons to expand the indications to include more proximal and distal fractures. Malalignment has become a common problem in proximal-third fractures treated with locked nails because of the large discrepancy in size between the tibial nail and the wide tibial metaphysis. Valgus angulation and anterior displacement of the proximal fragment are the most common deformities. Valgus deformity can be caused by a portal that starts too far medially and is directed laterally. A medial parapatellar incision and impingement from the patella may cause a portal to be directed in this manner. In a biomechanical study, Henley et al. found that medial to lateral screws in one plane can allow the nail to slide on the screws. Apex anterior angulation or anterior displacement can be caused by a portal that starts too distally or is directed too posteriorly. Some proximal-third tibial fractures can best be treated by other methods. Bono et al. developed an algorithm that is helpful in treatment decision making

FRACTURES OF DISTAL TIBIAL SHAFT

Intramedullary nailing of more distal fractures is possible, but the ability to maintain a mechanically stable reduction becomes more difficult the farther the fractures extends distally.

EXTERNAL FIXATION

External fixation is a useful and versatile tool in the treatment of tibial fractures. Three distinct types of fixators are commonly used: half-pin fixators, wire and ring fixators, and hybrid fixators that combine half-pins and tensioned wires.

OPEN TIBIAL SHAFT FRACTURE

The results of treatment of open high-energy tibial fractures have improved significantly because of important contributions made by large trauma services. Several factors are important for a good outcome in these fractures. Aggressive and repeated debridements of all devitalized tissue, including large fragments of bone, are essential. Because vascular soft tissue and bone are essential for resisting infection and providing a bed for reconstruction, the tibia should be stabilized with as little additional devascularization as possible. Gustilo and others stressed the importance of leaving the wound open and repeating debridement every 24 to 48 hours until closure at 5 to 7 days by delayed primary closure, skin grafting, or skin flaps. Antibiotics should be used routinely with open fractures. Aminoglycosides are added to cephalosporins for type III open fractures, and penicillin is included for fractures with severe contamination. Soft tissue coverage by the fifth to seventh day should be obtained by delayed closure, skin grafting, or flap coverage. Although there is no dispute that soft tissue management is the most important factor in determining the outcome of open tibial fractures, the optimal method of fixation is debated. Sufficient stability of the fracture fragments and soft tissues usually can be obtained only by locked intramedullary nails or external fixation. Plate fixation has been associated with an unacceptably high incidence of infection.

PINS AND PLASTER FOR UNSTABLE TIBIAL SHAFT FRACTURE

Pins and plaster casting has been recommended in the past by Böhler, Moore, and Anderson and Hutchins. This "poor man's external fixation" consists of two 2.4-mm smooth Steinmann pins drilled transversely through the proximal fragment and one Steinmann pin placed transversely through the distal fragment or calcaneus. The pins are then incorporated in a plaster cast. The pins are removed at 3 to 6 weeks, and the patient is placed in a long leg walking cast. This method essentially has been replaced by conventional half-pin fixators, ring and wire fixators, and locked intramedullary nails as preferred treatment for most unstable fractures of the tibia. The reader is referred to earlier editions of this text for a more detailed description of this technique.

ISOLATED FRACTURES OF MEDIAL AND LATERAL MALLEOLI

Medial Malleolus

Nondisplaced fractures of the medial malleolus usually can be treated with cast immobilization; however, in individuals with high functional demands, internal fixation may be appropriate to hasten healing and rehabilitation. Displaced fractures of the medial malleolus should be treated surgically because persistent displacement allows the talus to tilt into varus. Avulsion fractures involving only the tip of the medial malleolus are not as unstable as those involving the axilla of the mortise and do not require internal fixation unless displacement is significant. Delayed internal fixation can be done if symptoms warrant. Fixation of the medial malleolus usually consists of two 4-mm cancellous lag screws oriented perpendicular to the fracture .Vertical fractures of the medial malleolus require horizontally directed screws.

Smaller fragments can be fixed with one lag screw and one Kirschner wire to prevent rotation Fragments that are too small or comminuted for screw fixation can be stabilized with two Kirschner wires and a tension .Fixation with a small semitubular buttress plate may be necessary to adequately stabilize vertical fractures that extend high into the metaphysis.

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Lateral Malleolus

Although fractures of the lateral malleolus without significant medial injury are common, the indications for open reduction of these fractures are still controversial. The maximal acceptable displacement of the fibula reported in the literature has ranged from 0 to 5 mm. In most patients, 2 to 3 mm of displacement is accepted, depending on the functional demands of the patient. Yablon, Heller, and Shouse demonstrated that displacement of the talus accompanies displacement of the lateral malleolus in bimalleolar ankle fractures and emphasized the importance of anatomical reduction of the lateral malleolus in these injuries. Biomechanical studies by Brown et al. and Michelson, Helgemo, and Ahn showed that isolated fractures of the lateral malleolus do not disturb joint kinematics or cause talar displacement with axial loading. Long-term clinical follow-up studies by Bauer, Jonsson, and Nilsson and by Kristensen and Hansen of closed treatment of supination–external rotation stage II fractures reported 94% to 98% good functional results, even with 3 mm of fibular displacement. Yde and Kristensen found the results of operative treatment no better than those of closed treatment in supination–external rotation stage II injuries, even though only 1 of 35 patients (3%) who had closed treatment had anatomical reduction, compared with 28 of 34 (82%) with operative treatment. If the stability of a lateral malleolar fracture is uncertain, stress roentgenograms can be obtained with the ankle in supination and external rotation to detect displacement of the talus indicative of medial injury.

BIMALLEOLAR FRACTURE

Bimalleolar ankle fractures disrupt both the medial and lateral stabilizing structures of the ankle joint. Displacement reduces the tibiotalar contact area and alters joint kinematics. Closed reduction often can be accomplished but not maintained in anatomical position as swelling subsides. Nonunion has been reported in approximately 10% of bimalleolar fractures treated by closed methods, although these are not always symptomatic. Up to 20% of bimalleolar fractures involve intraarticular injuries to the talus and tibia; these injuries go untreated when closed methods are used. In a randomized, prospective study of 71 patients with bimalleolar or bimalleolar-equivalent ankle fractures, better results were obtained with operative than with nonoperative treatment

For most displaced bimalleolar fractures, we also recommend open reduction and internal fixation of both malleoli. Most Weber types B and C lateral malleolar fractures are stabilized with plate and screw fixation. In some patients, lateral hardware in the ankle is symptomatic.

SYNDESMOTIC INJURY

Syndesmotic injuries are most commonly caused by pronation–external rotation, pronation-abduction and, infrequently, supination–external rotation mechanisms (Danis-Weber types C and B injuries). These forces cause the talus to abduct or rotate externally in the mortise, leading to disruption of the syndesmotic ligaments.

Anatomical restoration of the distal tibiofibular syndesmosis is essential. If the fibular fracture is above the level of the distal tibiofibular joint, this joint is assumed to be disrupted and therefore must be anatomically reduced. In the past, internal fixation of all syndesmotic injuries was considered mandatory, but in a cadaver study Fixation of Lateral Malleolus

AFTERTREATMENT:The ankle is immobilized in a posterior plaster splint with the ankle in neutral position and elevated. If the bone quality is good and the fixation is secure, the splint can be removed in 2 to 4 days and replaced with a removable splint or fracture boot. Range-of-motion exercises are then begun. Weight bearing is restricted for 6 weeks, after which partial weight bearing can be started if the fracture is healing well. Full weight bearing is allowed after 12 weeks.

DELTOID LIGAMENT TEAR AND LATERAL MALLEOLAR FRACTURE

A deltoid ligament tear accompanied by a fracture of the lateral malleolus is caused by the same mechanism that produces bimalleolar fractures, that is, supination with external rotation of the foot. However, instead of the medial malleolus being fractured, the deltoid ligament is torn, allowing the talus to displace laterally. Usually the anterior capsule of the ankle joint also is torn. The deltoid ligament, especially its deep branch, is important to the stability of the ankle because it prevents lateral displacement and external rotation of the talus. A deltoid ligament tear should be suspected if a fracture of the lateral malleolus is accompanied by tenderness, swelling, and hematoma on the medial side of the ankle. A routine anteroposterior roentgenogram may show no lateral displacement of the talus, but a roentgenogram made when the ankle is stressed into supination and external rotation shows displacement and tilting of the talus in the ankle mortise and a wide medial clear space (more than 4 to 5 mm). This roentgenogram should be obtained with the ankle in neutral position. With the ankle in plantar flexion, the narrowest portion of the talus is within the mortise, which may appear to be wide even without injury. This latter roentgenogram usually can be made without a general anesthetic if an appropriate drug is given, such as morphine or diazepam (Valium). We have had little experience with the use of ankle arthrography to determine the extent of ligamentous injuries about the ankle.

Closed treatment of these injuries is difficult because the talus tends to shift in the mortise. A 1-mm lateral shift of the talus can reduce the effective weight-bearing area of the talotibial articulation by 20% to 40%, and a 5-mm shift can reduce it by 80%. If closed treatment is chosen, the patient must be followed closely for displacement. Optimal treatment of this injury provided the condition of the skin and the patient's age and general condition permit consist of open reduction and internal fixation of the fibula, with or without repair of the deltoid ligament. If only the deltoid ligament tear is repaired, the talus is likely to become displaced laterally after surgery despite the use of a cast. If only the fibular fracture is repaired, the deltoid ligament may be caught between the medial malleolus and the talus, preventing accurate reduction, or the ligament may be relaxed after healing.

AFTERTREATMENT: Aftertreatment is the same as that described on Deltoid Ligament Tear and Lateral Malleolar Fracture. After the fracture has united, a 5-mm medial heel wedge is placed in the shoe and can be used for 4 to 6 months.

TRIMALLEOLAR (COTTON) FRACTURE

Trimalleolar (Cotton) fractures require open reduction more often than any other type of ankle fracture. The results of treatment of trimalleolar fractures usually are not as good as those obtained for bimalleolar fractures. Trimalleolar fractures usually are caused by an abduction or external rotation injury. In addition to fractures of the medial malleolus and fibula, the posterior lip of the articular surface of the tibia is fractured and displaced, allowing posterior and lateral displacement and external rotation with supination of the foot. The medial malleolus may remain intact, with a tear of the deltoid ligament occurring instead of a malleolar fracture.

The same principles and indications for open reduction as previously outlined for bimalleolar fractures apply to trimalleolar fractures. Indications for open reduction of the posterior malleolus or posterior tibial fragment depend chiefly on its size and displacement.

In fractures with posterior malleolar fragments that constituted 25% or more of the joint, Harper and Hardin found no clinical differences between those that were reduced and fixed and those that were not fixed. They noted that reduction of the posterior malleolar fragment generally was satisfactory when the lateral malleolar fracture was reduced and fixed. Furthermore, this reduction was well maintained, and late posterior subluxation of the talus did not occur with either method.

FRACTURE OF ANTERIOR TIBIAL MARGIN AT ANKLE JOINT

The treatment of fractures of the anterior margin of the tibia is about the same as that for the posterior margin, although in reverse. However, the fractures differ in one respect: because fractures of the anterior margin usually are caused by a fall from a height that results in the foot and ankle being forcefully dorsiflexed, crushing of the articular surface of the tibia is likely to be more severe in these fractures. Thus, perfect restoration of the articular surface of the tibia may not be possible. When necessary, associated fractures of the medial and lateral malleoli are treated as described previously. These fractures lie in the spectrum of severity between simple malleolar fractures and pilon fractures. Surgery should be performed within the first 24 hours or delayed until the soft tissue

TIBIAL PILON FRACTURE

The terms tibial plafond fracture, pilon fracture, and distal tibial explosion fracture all have been used to describe intraarticular fractures of the distal tibia. These terms encompass a spectrum of skeletal injury ranging from fractures caused by low-energy rotational forces to those caused by high-energy axial compression forces arising from motor vehicle accidents or falls from a height. High-energy fractures frequently are associated with open wounds or severe, closed, soft tissue trauma. The fracture may have significant metaphyseal or articular comminution or diaphyseal extension. Classification of these fractures is important in determining their prognosis and choosing the optimal treatment. The fibula is fractured in 85% of these patients, and the degree of talar injury varies.

Rotational fracture of the ankle can be viewed as a continuum, progressing from single malleolar fractures to bimalleolar fractures to fractures involving the distal tibial articular surface. Lauge-Hansen described a pronation-dorsiflexion injury that produces an oblique medial malleolar fracture, a large anterior lip fracture, a supraarticular fibular fracture, and a posterior tibial fracture. Giachino and Hammond described a fracture caused by a combination of external rotation, dorsiflexion, and abduction that consisted of an oblique fracture of the medial malleolus and an anterolateral tibial plafond fracture. These fractures generally have little comminution, no significant metaphyseal involvement, and minimal soft tissue injury. They can be treated similarly to other ankle fractures with internal fixation of the fibula and lag screw fixation of the distal tibial articular surface through limited surgical approaches.

OPEN REDUCTION AND PLATE FIXATION

For displaced fractures, operative treatment has been found to be superior to nonoperative treatment. Rüedi and Allgöwer popularized the technique of open reduction and internal fixation with plates and screws for tibial pilon fractures in the 1960s. This technique follows the AO principles of anatomical reduction, rigid stabilization, and early motion. First, the fibula is reduced and stabilized with a plate. Then the articular surface of the tibia is reduced and provisionally fixed with Kirschner wires through an anteromedial incision. Metaphyseal defects are filled with bone graft, and the fracture is stabilized with a medial buttress plate

OSTEOCHONDRAL KNEE FRACTURE

The Army Air Force conducted a survey of approximately 186 patients with loose bodies in the knee. In 21 of these, the loose bodies were the result of osteochondral fractures of either the femur or the patella. Similar fractures have been reported by Rosenberg, Ahstrom, and Kennedy, Grainger, and McGraw. Rosenberg found osteochondral fractures of the lateral femoral condyle to be more common in adolescent boys and suggested that they often were caused by dislocation of the patella, which shears off a fragment of the condyle in much the same way as osteochondral fractures of the patella are produced (Milgram). Kennedy, Grainger, and McGraw suggested that osteochondral fractures of the femoral condyles also can be caused by a direct blow or twisting movement on a weight-bearing flexed knee.

According to Milgram, the mechanism of injury to the patella is as follows. The patella is momentarily subluxated over the lateral condyle with enough force to score the articular surfaces of both the patella and the femur. The medial border of the patella is then caught against the prominent edge of the femoral condyle. As the quadriceps muscle snaps the patella back into place, the edge of the femoral condyle shears an osteochondral fragment from the inferior and medial edge of the patella. Frandsen and Kristensen described a similar mechanism with forced internal rotation of the femur against the tibia, resulting in dislocation of the patella and fracture of the lateral femoral condyle.

Osteochondral fractures of the knee occur most commonly in adolescents and young adults, often with a history of patellar dislocation or a twisting injury to the knee associated with a painful snap. A hemarthrosis is present in acute injuries, and medial tenderness indicative of a medial retinacular tear is common. . A high index of suspicion must be maintained for these injuries in adolescents or young adults seeking treatment for an acute hemarthrosis of the knee. High-quality anteroposterior, lateral, skyline, tunnel, and oblique roentgenograms should be obtained if an osteochondral fracture is suspected. .

A variety of fixation methods have been advocated for osteochondral fractures of the knee, including metal pins, allograft cortical bone pins, Herbert screws, Acutrac conical screws, absorbable sutures, and absorbable rods. The fixation device must not protrude through the articular surface into the joint, or else severe damage may result. Metal pins usually require removal after fracture healing because of their tendency to migrate. Investigation of resorbable fixation devices has produced clinical and experimental evidence that resorbable polydioxanone rods provide satisfactory fixation of osteochondral fractures.

Aftertreatment for surgically fixed osteochondral fractures consists of 3 to 6 weeks of immobilization and 6 to 12 weeks of protected weight bearing, depending on the adequacy of fixation and the location of the fracture.

If the diagnosis and surgery are delayed, the edges of the fragment and the defect become rounded, and exact fitting is not possible. The fragment should be excised, the cancellous bed where the fragment originated should be smoothed, and any detached or frayed edges of cartilage should be excised sharply and vertically rather than beveled or shaved down. If the area involved is small and does not involve a weight-bearing surface, little if any disability usually results from removal of the fragment.

COMPLICATIONS:

• Neurovascular compromise

• Compartment syndrome

• Peroneal nerve injury

• Infection

• Gangrene

• Osteomyelitis

• Delayed union, nonunion, or malunion

• Amputation or skin loss

• Posttraumatic arthritis

• Fat embolism

PROGNOSIS:

• Tibia and fibula fractures

• Prognosis is generally good yet is dependent on degree of soft-tissue injury and bony comminution.

• Prognosis is good for isolated fibula fractures.

REFERENCES

• Accousti WK, Willis RB: Tibial eminence fractures. Orthop Clin North Am 2003 Jul; 34(3): 365-75[Medline].

• Germann CA, Perron AD, Sweeney TW: Orthopedic pitfalls in the ED: tibial plafond fractures. Am J Emerg Med 2005 May; 23(3): 357-62[Medline].

• Haller PR, Harris CR: The tibia and fibula. In: Emergent Management of Skeletal Injuries, 1st ed. St Louis: Mosby-Year Book; 1995: 499-517.

• Khalily C, Behnke S, Seligson D: Treatment of closed tibia shaft fractures: a survey from the 1997 Orthopaedic Trauma Association and Osteosynthesis International--Gerhard Kuntscher Kreis meeting. J Orthop Trauma 2000 Nov; 14(8): 577-81[Medline].

• Krieg JC: Proximal tibial fractures: current treatment, results, and problems. Injury 2003 Aug; 34 Suppl 1: A2-10[Medline].

• McKoy BE, Stanitski CL: Acute tibial tubercle avulsion fractures. Orthop Clin North Am 2003 Jul; 34(3): 397-403[Medline].

• Mustonen AO, Koskinen SK, Kiuru MJ: Acute knee trauma: analysis of multidetector computed tomography findings and comparison with conventional radiography. Acta Radiol 2005 Dec; 46(8): 866-74[Medline].

• Roberts DM, Stallard TC: Emergency department evaluation and treatment of knee and leg injuries. Emerg Med Clin North Am 2000 Feb; 18(1): 67-84, v-vi[Medline].

• Russell TA: Fractures of the Tibia and Fibula. In: Fractures in Adults, 4th ed. Philadelphia: Lippincott-Raven; 1996: 2127-2201.

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