Additional videos related to the subject of this chapter are available from the Medizinische Hochschule Hannover collection. The following videos are included with this chapter and may be viewed at expertconsult.inkling.com :
Lateral tibial plateau fracture–surgical approach.
Posterior approach for proximal tibia fractures.
Introduction: Scope and Purpose
Tibial plateau fractures involve the articular surface and adjacent metaphysis of the proximal tibia. Tibial plateau fractures accounted for 1.2% of the fractures treated in Edinburgh’s population of more than 500,000 during the year 2000, ranking 16th of the 27 reported anatomic fracture locations. This is approximately the same frequency as fractures of the calcaneus and humeral shaft. The age distribution of tibial plateau fractures follows a bimodal distribution in both males and females, with peaks occurring in young adults, with high-energy mechanisms predominating and again in the elderly adults with osteoporosis, in whom low-energy mechanisms are common. An increasing frequency is noted in survivors of high-speed motor vehicle accidents (MVAs) in regions where restraints and airbags are commonly used. With increasing aging of the number of fragility fractures affecting the proximal tibia also appears to be growing.
The tibia plateau is particularly vulnerable to both high-energy and low-energy injury mechanisms because of its exposed and unprotected position in the lower extremity. It must bear significant weight and sustain significant impact and deceleration forces with little osseous constraint and has scant surrounding soft tissue and a tethered medial and lateral integument. Furthermore, the tibial plateau has relatively forgiving ligamentous attachments that must allow for a large range of motion in a single plane. Given the diversity of injuries seen, management of these fractures has come to include a wide variety of acceptable treatment strategies.
Significant advances have been made in the diagnosis and treatment of these injuries. Over the past decade, greater knowledge and appreciation have been gained for the extent of associated soft tissue lesions in and around the knee, with resultant increased use of computed tomography (CT) scans and magnetic resonance imaging (MRI). Furthermore, indications and outcomes for various treatment strategies continue to be refined, as well as the most appropriate surgical approaches to treat various fracture patterns. The advent and routine application of staged protocols with delayed surgery as well as an emphasis on minimally invasive surgical strategies with gentle handling of soft tissues have contributed to decreased complication rates historically seen with these injuries. Additionally, increased familiarity with arthroscopically assisted management of appropriate variants has added an additional option. Finally, more bone graft substitutes options continue to become available for dealing with bone defects.
With all due respect to these emerging strategies, optimal management of tibial plateau fractures demands an appreciation of the history of the treatment of these fractures. This chapter looks at this history closely with an eye on the treatment pendulum, attempting to understand how new surgical trends might address known complications while striving to avoid repeating the errors of the past.
Mechanism of Injury and Biomechanics
The healthy knee exhibits complex motion. This includes not only flexion–extension in the sagittal plane (normally 0–140 degrees) but also axial rotation and backward “rolling” or “rollback” of femur on tibia. The terminal rotatory component is often referred to as the “screw home mechanism.” As the knee reaches terminal extension, the tibia externally rotates until it “locks” in full extension. Some patients, particularly females, have physiologic recurvatum of 5 to 10 degrees, indicating hyperextension from ligamentous laxity, which may predispose them to certain injuries.
The concept of femoral “rollback” is important in the understanding of knee kinematics. The knee joint is more complex than a simple hinged joint. Thus, its axis is not a point but a path of instant centers, located in the femoral epicondylar region. As the knee flexes, the femur translates or “rolls back” posteriorly on the tibia, while the tibia internally rotates on the femur. Therefore, depressed fracture fragments in the middle and posterior regions of the tibial plateau may be more critical with regard to fracture reduction and restoration of normal knee kinematics.
Mechanism of Injury
Injuries to the plateaus occur most commonly as a result of (1) a force directed either medially (valgus deformity, the classic “bumper fracture”) or laterally (varus deformity), (2) an axial compressive force, or (3) both an axial force and a force from the medial or lateral side. The respective femoral condyle in this mechanism of injury exerts both shearing and compressive forces on the underlying tibial plateau. The resulting fracture is therefore most commonly a split fracture or a depression fracture, or both. Pure split fractures are more common in younger patients, in whom the strong subchondral bone of the tibial condyle is able to withstand the compressive force of the overlying femoral condyle, but the shear component of the load produces a split in the condyle. With age, the dense cancellous bone of the young tibial condyle becomes osteopenic, with diminished physical properties; it is no longer able to withstand compressive forces as well. As a result, split-depression fractures become common in patients after the fifth decade of life. These fractures typically result from low-energy injuries, usually simple slip and fall accidents.
A less common but increasingly recognized mechanism of injury involves a combined hyperflexion and valgus injury. This results in an isolated posterolateral tibial plateau split-depression fracture. Approximately 7% of fractures occur in this region of the plateau, and alternative surgical approaches are typically required to address them.
As noted, fracture patterns reflect the magnitude and direction of the forces involved. Kennedy and Bailey were able to produce many of the commonly observed plateau fracture patterns by subjecting cadaver knees to valgus or varus forces combined with axial loads in the range of 1600 to 8000 lb. Valgus loads in the range of 2250 to 3750 inch-pounds produced mixed fractures with large variations in the amount and degree of joint impaction and condylar separation. These forces were thought to be comparable to those seen in the classic bumper fracture. This is a fracture of the lateral plateau, the result of a lateral blow to the leg that creates a valgus deforming force and a loading of the lateral plateau by the overlying femoral condyle. In high-energy injuries, the forces may be so great that the plateau fractures into numerous fragments. When axial loading exceeded 8000 lb, severely comminuted fractures were produced in biomechanical studies. This mechanism is seen typically after a fall from a height or after a MVA occurring with an axial load delivered to an extended knee.
The magnitude of the force determines not only the degree of fragmentation but also the degree of displacement. In addition to the fracture, there may be associated soft tissue lesions of the ligaments or menisci. Some investigators believe that an intact collateral ligament on one side of the knee is necessary for a fracture to occur on the contralateral side. The lateral collateral ligament (LCL) acts in a similar way, with varus forces causing medial plateau fractures with an associated tear of the LCL complex, the posterior cruciate, and the peroneal nerve or a lesion of the popliteal vessels. With the increased use of MRI for evaluating these fractures, recognition of associated ligamentous injuries has increased. The surgeon must also differentiate split fractures that are the result of a shearing force from rim avulsion fractures that are associated with knee dislocations and may indicate an unstable injury.
Consequences of Injury
Tibial plateau fractures pose major threats to the structure and function of the knee joint. Immobilization alone in a plaster cast, if prolonged for more than 2 to 3 weeks, may result in an unacceptable degree of stiffness that does not respond to physiotherapy. Traction with early motion preserves movement but does not ensure reduction because impacted articular fragments, which are driven into the underlying cancellous bone of the metaphysis, do not have any soft tissue attachment and are not reduced. The joint depression together with metaphyseal fragmentation may also result in an angular deformity, leading to a major degree of joint overload.
Unless the joint is adequately reduced with appropriate alignment and stability of the limb preserved and early range of motion instituted, major complications can be anticipated. Delayed mobilization results in permanent stiffness. Failure to restore bone anatomy and ligament function may result in permanent instability, which alone or when coupled with joint incongruity leads to posttraumatic arthritis. Even with the most successful form of treatment, posttraumatic arthritis can develop, depending on the degree of initial joint fragmentation and damage to the articular cartilage.
Tibial plateau fractures are often associated with serious soft tissue damage. Tears of the menisci, particularly peripheral detachments, occur frequently, as do tears of the collateral and cruciate ligaments.
Fractures of the lateral plateau are rarely associated with arterial or nerve lesions. However, fractures of the medial plateau, because they are invariably associated with much greater violence and often represent a knee dislocation that has been realigned, are frequently associated with lesions of the peroneal nerve or the popliteal vessels. The arterial lesions are rarely seen as hemorrhage. They are commonly seen either as an acute obstruction (because of a complete tear in the vessel or an acute thrombosis) or as a delayed thrombosis or a thrombosis seemingly initiated by the reparative surgery. The reason is that the injury to the artery is typically a small intimal tear, which may enlarge or initiate clotting, or both.
Tibial plateau fractures, particularly if they extend into the diaphysis, may be associated with acute compartment syndromes because of hemorrhage and edema of the involved compartments. Another important cause of compartment syndrome is reperfusion after successful treatment of arterial occlusion or interruption.
The proximal tibia is subcutaneous except posteriorly. Anteriorly, it is covered only by the skin and subcutaneous tissues that overlie the tendons and ligaments that cross the joint. The bone, together with the tendons and ligaments, are at risk for necrosis if skin coverage is lost. Severe contusions of this skin envelope occur particularly with high-energy injuries to the area. Therefore, even in the absence of open fractures, the contused soft tissue envelope may be in jeopardy because of instability of the underlying fracture; severe swelling associated with the injury; or any injudicious, traumatizing, or poorly timed surgical procedure. Fractures of the proximal tibia may become complicated by wound sloughs, infections, and osteomyelitis.
How an injury was sustained is an important clue to its severity. The surgeon should try to understand the mechanism causing the fracture. This mechanism should suggest the likelihood of significant soft tissue injury, ligament disruption, or vascular injury. For example, a lateral plateau fracture sustained by a pedestrian struck by an automobile is completely different from one caused by a misstep off a curb.
The history ideally indicates the direction of the force of injury, which is helpful in predicting soft tissue injury and guides further evaluation. For example, whereas a valgus force to the lateral knee in a football player may suggest a medial collateral ligament (MCL) injury, a witnessed hyperextension deformity may indicate disruption of cruciate ligaments and vascular injury. An axial load sustained during a MVA with the knee in extension implies a crushing mechanism that may create more articular damage or soft tissue swelling.
Some patient-related considerations are important to determine during the history-taking process. Age and bone quality are generally related, with younger patients having denser bone. A young adolescent may be skeletally immature and sustain a growth plate injury. A comminuted fracture in an elderly versus a young patient carries completely different implications when considered along with the injury mechanism. Sometimes knowing the age may tip the surgeon off to important comorbidities; for example, a 40-year-old man with osteoporotic bone and a comminuted fracture after a fall down stairs may be a malnourished alcoholic. Proximal tibial fractures, particularly the more severe ones, occur in vehicular incidents or falls from a height. The possibility of other, potentially occult, injuries must always be remembered, and the whole patient must be evaluated accordingly.
It is important to ascertain comorbidities in these patients because soft tissue considerations must guide surgical choices. As an example, smoking, diabetes, vascular disease, and congestive heart failure all negatively affect the healing capacity of surgical wounds. Last, a patient’s activity level, employment status, and recreational diversions say a lot about such issues as motivation, compliance, and physical demands after surgery.
Examination of a patient with a known or possible tibial plateau fracture begins, as it should for any injured patient, with the advanced trauma life support (ATLS) routines of primary and secondary survey. Immediate attention may need to be directed to resuscitation and treatment of injuries that threaten life or limb. The possibility of a popliteal arterial injury arises with any significant knee trauma. Its rapid identification and surgical treatment are indeed limb saving and are discussed in some detail later on. Knee evaluation is part of the secondary survey unless exsanguinating local hemorrhage is present.
Frequently, the orthopaedic trauma surgeon is called to see an injured patient whose radiographs demonstrate a tibial plateau fracture. Even if the radiographic diagnosis is known, particularly if the patient is unable to communicate, attention must be paid to signs of open wounds, swelling, deformity, instability, or crepitus. Distal pulses must always be examined, as should compartmental soft tissue swelling and turgor. For high-energy injuries, a thorough vascular assessment with documentation of an arterial pressure index (API) is mandatory.
Even if the API is greater than 0.9, serial clinical examination, focused on swelling, motor function, sensation, and stretch pain, is advisable because patients with tibial plateau fractures and intact arteries may develop compartment syndrome during the first few days after injury (or surgery). If the API is less than 0.9, further vascular workup with an arteriogram is immediately necessary. We strongly recommend measurement of relative arterial pressure . Too often, physicians have focused on whether a pedal pulse is palpable or identifiable with a Doppler device. But this approach is not sensitive enough to exclude reliably a limb-threatening arterial injury. Relative arterial pressure measurement compares the Doppler-aided systolic pressure of an injured lower extremity with that in an uninjured limb, which could be the opposite lower extremity, or perhaps more conveniently an uninjured upper extremity (also referred to as ankle-brachial index [ABI] ( Fig. 62-1 ). API measurement may be inaccurate in patients with risk factors for peripheral arterial disease, such as diabetes and hypertension. Vessel calcification, as seen in elderly adults, may also increase the risk of false-positive results. It has been shown that when the API falls within the normal range, no further diagnostic screening is necessary. However, it is imperative to continue to observe the patient’s lower extremity vascular status with serial physical examinations.
If possible, a neurologic examination to assess sensation and voluntary motor function is essential and must be repeated periodically during the first day or two after injury. Both light touch and muscle strength of the tibial, superficial, and deep peroneal nerves must be assessed and documented. These signs may indicate peroneal nerve damage or a compartment syndrome, for example. Firmness of the calf muscle compartments suggests this problem. Pain with passive stretch of the foot and ankle flexors and extensors is a critical finding. Progressive deterioration of sensation or motor function must always be assumed to indicate the development of compartment syndrome. When compartment syndrome develops, surgical release of the compartments should be performed along with application of external fixation to stabilize the fractures and allow for continued evaluation and treatment of the soft tissue envelope ( Fig. 62-2 ).
Recognition, assessment, and monitoring of soft tissue swelling are crucial to avoid missing a compartment syndrome and to help decide about the timing of surgery, as well as the possible need for temporary external fixation. The injured knee must be compared with the opposite (hopefully uninjured) side. Particularly with severe injuries and in patients who arrive in shock, the initial appearance of the wound may not suggest damage that will become evident over the next 2 to 3 days. Excessive skin mobility or subcutaneous fluctuance may be the only suggestions of significant degloving of the subcutaneous tissue from the deep fascia. Abrasions that appear superficial may progress to full-thickness eschars. Additional signs include ecchymosis, edema, and blistering (particularly if the fluid is bloody), and shiny skin that lacks normal wrinkles and is still swollen is at risk for wound slough if it is further injured by a surgical incision ( Fig. 62-3 ). Normal wrinkling is the best indication that swelling has resolved to the point that the surgeon can proceed with definitive care.
In low-energy injuries with minimally displaced fractures, an attempt at examining for stability with both gentle varus and valgus stress at 0 and 30 degrees is advisable. Any knee radiograph demonstrating displaced fractures should obviate such an examination. A patient with minimal deformity and a stable knee usually does not need surgical treatment for a tibial plateau fracture. A Lachman examination for anterior cruciate ligament (ACL) deficiency may also be attempted. Range of motion may be assessed in a gentle fashion. A straight leg raise assesses extensor mechanism integrity; however, these aspects of the examination are frequently limited by patient discomfort.
Proximal Fibular Fractures.
In a recent retrospective series by Bozkurt and colleagues, 14 of 55 patients who presented with tibial plateau fractures had an associated proximal fibular fracture. The effect of these fractures on the prognosis of these patients was significant, in that patients who had such associated fractures complained of lateral hamstring tightness and persistent lateral-sided knee pain, whereas those who did not have a proximal fibular fracture did not experience these symptoms. However, treatment of proximal fibular fractures associated with tibial plateau fractures remains controversial. Options include open reduction and internal fixation (ORIF) with plates, screws, sutures, or combinations thereof depending on the fracture configuration. It is a reasonable approach to fix the tibial fracture and then examine the knee for instability. If the instability then includes a significant varus laxity in the setting of a fibular head fracture or if marked posterolateral rotatory instability is found, then formal reconstruction should be considered. This is discussed later.
Tibial Tubercle Fractures.
Tibial tubercle fracture together with avulsion of the infrapatellar tendon occurs commonly in association with high-energy fracture patterns, often demonstrating a fracture through the tibial tubercle with associated posterior cortex comminution, which would prevent typical lag screw fixation of this fragment. These occur in association with Schatzker type V and VI fractures in particular, although their incidence has not been defined. This injury represents a disruption of the extensor mechanism and must be addressed at the time of definitive fixation.
These injuries may easily be missed in many cases unless the examiner is vigilant. The significance of such a fracture, if missed and left unfixed, is that the patient will rehabilitate poorly because of pain and at times displace the fragment and develop an extension lag that is unrecoverable. Additionally, the presence of such a fragment may cause skin tenting and require that external fixation be applied with the knee in full extension to prevent pressure necrosis.
Because it is an avulsion fracture in the coronal plane, a poorly performed knee lateral radiograph frequently can miss the fracture plane entirely. More commonly, however, the examiner is distracted by the more impressive displaced fragments of the medial and lateral plateaus, whose comminution blends in with a tubercle fragment. It is always wise to assess the level of the patella, as well as the integrity of the tibial tubercle, to reduce the risk of missing this component of a tibial plateau fracture. They may also be overlooked on CT when comminution may again be misleading. Sagittal plane two- and three-dimensional (3-D) reconstruction images may best demonstrate tibial tubercle fractures, so they should be reviewed carefully with this possibility in mind ( Fig. 62-4 ).
Intercondylar Eminence Fractures.
There are many intercondylar eminence fractures as a component of high-energy tibial plateau fractures, in particular Schatzker types IV, V, and VI ( Fig. 62-5 ). They are usually cruciate ligament avulsions. Thus their repair should help restore long-term knee stability. Isolated fractures of the intercondylar eminence also are seen. These typically represent pure cruciate ligament avulsions and may not involve the actual articular surfaces of the tibial plateau.
Soft Tissue Injuries.
Many authors have now recognized the high association of meniscal, collateral, and cruciate ligament injuries. Stannard and colleagues performed MRI on 103 patients with high-energy mechanisms. They found 71% of patients tore at least one major ligament group, and 53% tore multiple ligaments. Additionally, the authors found that 49% sustained a meniscal tears. Gardner and colleagues used MRI to analyze 103 consecutive acute tibial plateau fractures. The authors found that only one patient in the entire series had no evidence of soft tissue injury. This incidence was significantly higher than previous reports in the literature, which range from 7% to 97%. Shepherd and colleagues reviewed MRI of 20 consecutive tibial plateau fractures that were deemed nonoperative based on the degree of displacement and found 90% of the patients had injuries to at least one ligament or meniscus based on MRI.
Meniscal tears are common in tibial plateau fractures. Stannard and colleagues performed MRI on 103 patients with high-energy mechanisms. There were 66 patients with Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association (AO/OTA) type 41C fractures and 37 patients with AO/OTA type 41B fractures. They found that 50 patients (49%) sustained a total of 60 meniscal tears, with 25 medial menisci and 35 lateral menisci injuries found. Whereas medial meniscus tears were most commonly found in Schatzker type V fractures (38%), lateral meniscus tears were most commonly found in Schatzker type II fractures (55%).
In a previous report by Gardner and colleagues, 103 consecutive patients with tibial plateau fractures were assessed by MRI. The authors found 91% of the patients had evidence of a torn or peripherally separated meniscus. Medial meniscal tears were found in 44% of patients. It is important to recognize that 60% of the fractures in their series were Schatzker type II fractures, of which 73% had injuries to the lateral meniscus. Another important finding is that lateral capsular separation occurred in 100% of the Schatzker type I plateau fractures seen in their series. Medial tibial plateau fractures were associated with a medial meniscal tear rate of 86%.
The incidence noted by Gardner and colleagues is higher than in previous or subsequent reports. In a study by Vangsness and associates of 36 consecutive patients with tibial plateau fractures, only 47% had associated meniscal pathology. In a study by Colletti and colleagues, lateral meniscal tears were noted in 45% and medial meniscal tears in 21% of patients in a series of 29 cases with tibial plateau fractures assessed by MRI. In another study by Bennett and Browner, 30 tibial plateau fractures were evaluated with diagnostic arthroscopy, revealing an overall meniscal pathology rate of only 20%. In a previous study, Gardner and colleagues examined 62 consecutive patients with Schatzker type II (lateral tibial plateau) fractures who underwent imaging with radiographs as well as MRI preoperatively. The authors found that depression greater than 6 mm and widening greater than 5 mm on a standard radiograph was associated with a lateral meniscal injury rate of 83% compared with 50% among fractures with less displacement. The authors suggested that in Schatzker type II tibial plateau fractures with depression or widening of at least 5 mm, surgeons should suspect concomitant soft tissue injuries. (See Video 62-1.)
It is clear by the variation in incidence among these studies that either there are different interpretations for what represents a meniscus tear or the technique or quality of the MRI examinations is different. The arthroscopist may fail to detect certain very anterior lesions, where they are likely to occur in lateral plateau fractures. Treatment of meniscal pathology is controversial because the natural clinical history of all these variants is unknown. Regardless, the critical role of the menisci has been well established. In a classic article by Walker and Erkman, contact stress analysis was performed on both medial and lateral tibial plateaus under various loads. Under no load, contact between the femoral condyles and their respective medial and lateral articulations occurs primarily on the menisci. Under loads of up to 150 kg, the lateral meniscus carried most of the load, but on the medial side, the load was shared almost equally between the meniscus and the exposed cartilage of the medial tibial plateau. In this context, it seems that the importance of the lateral meniscus in particular and its role in stabilizing the knee joint cannot be overstated. If one considers the results of total meniscectomy in the development of posttraumatic arthrosis as noted by Fairbank, it seems intuitive that preserving the lateral meniscus is of prime importance. Peripheral meniscal detachments constitute the majority of meniscal injuries. Although radial tears of the meniscus should usually be débrided, peripheral detachments, often involving the outermost portion of the meniscus or its anchorage to the joint capsule, should be repaired to the coronary ligaments or even to a plate or screws as the implants and injury may dictate. A durable nonabsorbable monofilament suture is best used for this task. Suture anchors can be helpful in the cases in which reattachment is difficult because of poor integrity of the coronary ligaments. Perhaps most important, the presence of a peripheral meniscal tear in association with a tibial plateau fracture should never be considered an indication for meniscectomy.
It is possible that simply reducing a displaced plateau fragment approximates the coronary ligaments to the peripheral meniscal detachment and allows for healing without formal repair. This could explain the disconnect between the low rate of reported late complications related to meniscal tears and the high frequency with which present-day MRI detects such injuries acutely. In any case, maintenance of the menisci is critical because one study found that removal of a meniscus during the fracture surgery resulted in secondary degeneration in 74% of the cases compared with 37% when the meniscus was intact or repaired.
Collateral Ligament Injuries.
Several other studies have been performed to determine the incidence of collateral ligament injury associated with tibial plateau fractures. Methods of diagnosis in these different investigations vary from physical examination to operative findings to arthroscopy and MRI. The overall incidence ranges between 8% and 45%. Delamarter and Hohl reviewed 39 tibial plateau fractures and noted that ligamentous injury occurred in all types of tibial plateau fractures but most commonly in split-depression and pure depression injuries. In Schatzker type II tibial plateau fractures, Gardner and colleagues noted a fibular collateral ligament tear incidence of 18% and in 36% of the MCLs. In their report of 103 operatively treated tibial plateau fractures, 29% of patients had complete fibular collateral ligament tears, 47% had partial fibular collateral ligament tears, 33% had complete MCL tears, and 57% had partial MCL tears. In this series, 60% were Schatzker type II fractures. In the series by Colletti and colleagues, fibular collateral ligament injuries were discovered in 34% of patients and MCL injuries in 55%. These more recent studies demonstrate again that ligament injuries were underappreciated in previous reports. Bennett and Browner, in their study of 30 tibial plateau fractures, found an MCL lesion in only 20% of the patients and fibular collateral ligament lesions in only 3% based on diagnostic arthroscopy, physical examination, and stress radiographs ( Fig. 62-6 ).
Cruciate Ligament Injuries.
Injuries to the ACL and posterior cruciate ligament (PCL) in the setting of tibial plateau fractures have been described in numerous series. In Stannard and colleagues’ report on 103 tibial plateau fractures that underwent preoperative MRI, the authors found ACL injuries in 45 patients (44%), most commonly in Schatzker type V variants, occurring in eight of 13 (62%). They were found in all variants, however, ranging from 15% to 62%.
In Gardner and colleagues’ previous preoperative MRI study of 103 patients with tibial plateau fractures, significant ACL injuries occurred in 57%. In contrast to the study by Stannard, Gardner found Schatzker type II fractures rather than type V had the highest rates of complete ACL tears; however, footprint avulsions were noted in 71% of bicondylar Schatzker type V fractures but were common among all tibial plateau fracture types, ranging from 42% to 71%. In a more recent study by Gardner and colleagues, in Schatzker type II fracture patterns, the overall incidence of ACL injury was 47%, most of which were footprint avulsions. In Colletti’s series of 29 patients, 41% were noted to have injuries to the ACL. In Bennett and Browner’s series of 30 patients, injury to the ACL was noted in 10%.
The incidence of PCL injury is lower. Stannard and colleagues found PCL injuries in 41 patients (40%), most commonly in Schatzker type IV variants, occurring in seven of 13 (54%). Gardner and colleagues previously reported a rate of 28%. Most of these were avulsions of the PCL. Footprint avulsions of the PCL were highest in Schatzker type I fracture patterns with an incidence of 67%. In a more recent study by Gardner and colleagues reviewing Schatzker type II fracture patterns, 25% were noted to have PCL lesions, of which most were PCL footprint avulsions. In Colletti’s series of 29 patients, 28% were noted to have PCL injuries. Gardner and colleagues reviewed the literature of the reported incidence of associated soft tissue injuries in tibial plateau fractures and noted injury to the cruciate ligaments ranging from 8% to 69%. Bicruciate injuries were most common in Schatzker type IV variants in Stannard’s series, seen in six of 13 (46%).
Posterolateral Corner Injuries.
More recently, damage to the posterolateral corner supporting structures of the knee has been defined and appreciated. In particular, popliteal fibular ligament (PFL) and popliteus tendon (PT) tears have been described in association with tibial plateau fractures ( Fig. 62-7 ). Stannard and colleagues demonstrated injury to the posterolateral corner structures in 46 of 103 (45%) patients in their series. This injury was seen most commonly in Schatzker type IV and V variants, both occurring in 62% of patients. In their previous study series of 103 patients, Gardner and colleagues reported that 68% of patients had tears of the PFL, the PT, or both.
Neurovascular injury is rarely seen in most tibial plateau fractures. However, fracture-dislocations and high-energy medial condyle (Schatzker type IV) and bicondylar (Schatzker types V and VI) patterns do present an increased risk to neurovascular structures, in particular the popliteal artery and common peroneal nerve (CPN). Our current approach to vascular assessment is outlined in Figure 62-8 .
Although arteriography is rarely necessary if a patient has limb-threatening ischemia associated with a single fracture or dislocation, when more than one level of injury is present, it may be necessary for the vascular surgeon to localize the arterial obstruction. In such cases, imaging should be done rapidly with whatever technique is best suited to the needs of patient and vascular surgeon and is within the institutional capabilities: angiography in the operating room (OR), rapid arteriography by a radiologist, CT arteriography, duplex ultrasonography, and so on. Harrell and associates, in a retrospective review, noted that the incidence of popliteal artery injury with fractures about the knee was 3%, but clearly this rate is fracture specific and therefore institution specific, depending on the injury profile that presents to a given emergency department.
In a study by Bennett and Browner, only one patient in 30 had injury to the peroneal nerve, for an incidence of 3%. Myint and colleagues reported on a patient who sustained a CPN palsy caused by posterolateral displacement of a fractured lateral plateau.
Tibial plateau fractures represent a spectrum of bony and soft tissue injury. Because of the high rate of associated ligamentous injuries, most high-energy tibial plateau fractures should be considered fracture-dislocations. In other words, some tibial plateau fractures have associated significant ligamentous injuries that require reconstruction, and some knee dislocations have associated rim fractures of the tibial plateau that require fixation. The Hohl-Moore classification is often more helpful than that of Schatzker in classifying these fractures and predicting concomitant injuries and guiding treatment.
Bennett and colleagues in 2003 described anterior rim tibial plateau fractures with posterolateral corner injuries of the knee in 16 knees of 15 patients who had evidence of posterolateral corner injury on physical examination and MRI. Six knees showed evidence of tibial plateau fracture on MRI. Five of those six were anteromedial rim fractures. The authors concluded that anteromedial rim fractures of the tibial plateau occur rarely but are frequently seen in the setting of a posterolateral corner knee injury ( Fig. 62-9 ).
It is important to recognize the possibility of significant soft tissue envelope compromise and the high risk of associated popliteal artery injury, compartment syndrome, and peroneal nerve injury in severely displaced, high-energy plateau fractures. These patients typically require emergent attention, including preliminary fracture reduction and stabilization, typically with application of a knee-bridging external fixator.
Compartment syndrome is a devastating complication of tibial fractures, including the tibial plateau. Schatzker type VI fractures and medial plateau fracture-dislocations appear to be particularly at risk.
Park and colleagues retrospectively reviewed 414 patients and classified into three groups (proximal, diaphyseal, and distal) based on the anatomic location of the fractures (AO/OTA fractures 41, 42, and 43, respectively). The authors found the rate of compartment syndrome for 186 proximal tibial fractures was 1.6%.
As stated earlier, the risk has been found to be significantly greater than this in Schatzker type VI variants and medial plateau fracture-dislocations. Stark and colleagues retrospectively reviewed 67 patients with tibial plateau fractures and fracture-dislocations who were treated with initial external fixation within 48 hours of injury. There were 50 Schatzker type VI fractures and 17 fracture-dislocation variants. The authors found 18 compartment syndromes (27%) in 67 extremities. Compartment syndrome developed after Schatzker type VI fractures in nine of 50 (18%) and medial plateau fracture-dislocations in nine of 17 (53%). The authors recommended careful monitoring of Schatzker type VI fractures and especially medial plateau fracture-dislocations after placement of spanning external fixators.
Other authors have found no relationship between application of knee-spanning external fixation and compartment syndrome. Egol and colleagues prospectively evaluated intracompartmental pressures in all four compartments at four time points during the external fixator application. The authors found that application of knee-spanning external fixation for stabilization of high-energy proximal tibial fractures and dislocations in 25 patients and found only transient elevations of intracompartmental pressures.
Compartment syndrome in the setting of tibial plateau fracture can be managed effectively with both one- and two-incision fasciotomy surgical techniques. Placement of fasciotomy incisions should take into account plans for future incision placement during definitive fixation whenever possible.
Supine anterior-posterior (AP) and lateral radiographs are required for all patients with suspected or known fractures of the tibial plateau. Internal and external rotation oblique views of the knee are helpful in identifying and defining articular injuries. The internal rotation oblique displays the fibula in profile, eliminating tibiofibular overlap, because the fibula resides posterolateral to the tibia. This view demonstrates the posterolateral plateau and the anteromedial plateau. In contrast, the external rotation oblique projects the fibula more anteriorly, increasing tibiofibular overlap. This view provides better detail of the anterolateral and the posteromedial plateau surfaces ( Fig. 62-10 ).
The well-performed AP, lateral, and oblique radiographs of the knee typically provide the necessary information when assessed by experienced orthopaedic surgeons. As with many articular fractures, one should obtain contralateral AP and lateral radiographs so that normal anatomy, which varies, can be used for preoperative planning and intraoperative comparison. To restore the bony architecture to a preinjury state, the surgeon must have knowledge of the patient’s normal anatomy. Contralateral radiographs thus act as a template for fracture reduction, indicating tibial plateau height, condylar width and alignment in the coronal plane, and posterior slope of the tibial plateau in the sagittal plane ( Fig. 62-11 ).
In addition to the above views, the “tibial plateau view” can be obtained. As described by Moore and Harvey, an AP radiograph is obtained with the knee in full extension and the x-ray beam directed approximately 15 degrees caudally ( Fig. 62-12 ). This view parallels to the posterior slope of the tibial plateau and thus yields a better view of the joint surfaces. The exact angulation of the x-ray beam for a particular patient can be determined from the slope of the contralateral tibial plateau.
With appropriate interpretation of plain radiographs, many CT scans could be obviated. In many instances, well-done AP, lateral, and oblique views demonstrate perfectly well that there is minimal displacement of a fracture. If it is then clear that surgical indications are not met and that a patient is not an appropriate candidate given the displacement seen, then no CT scan is necessary. The examiner should obtain a CT scan if surgical consideration exists based on radiographic assessment of fracture displacement and pattern. With the advent of staged protocols using initial spanning external fixation, repeating the lateral and AP radiographs of the knee after application of the spanning external fixator is important to ensure that appropriate provisional length and alignment has been restored. Fracture fragment alignment is usually improved by ligamentotaxis during application of spanning external fixation.
In addition to defining osseous pathology, certain radiographic findings should also raise suspicion for injury to meniscal and ligamentous structures. Gardner and colleagues found that Schatzker type II fractures with greater than 5 mm of depression or condylar widening were often associated with significant soft tissue injuries. They recommended heightened vigilance and consideration of MRI evaluation preoperatively in these situations.
Computed Tomography Scanning
Several studies have demonstrated the utility of CT scans for assessing the degree of comminution and depression that is often underestimated with routine radiographs. In most cases, better alignment and elimination of fragment overlap in the posttraction setting aids interpretation of radiographs and CT scans. Thus, in cases in which staged management with an external fixator is planned, CT evaluation for the purposes of preoperative planning should not be performed until after the external fixator has been applied.
Standard two-dimensional (2-D) CT scans with standard coronal and sagittal reconstructions help to assess the degree of comminution, trajectory of fracture lines, and injury nuances, which can enhance the surgeon’s ability to develop a surgical tactic. Scout line functionality in many systems provides a better understanding of fracture characteristics. Routine 2-D axial views are now commonly supplemented by 3-D reconstructions, providing even the novice an excellent understanding of fracture morphology ( Fig. 62-13 ). However, it is unclear whether the addition of 3-D reconstructions to standard 2-D imaging improves reliability of classification of tibial plateau fractures. Hu and colleagues concluded that 3-D imaging was superior to 2-D imaging and significantly improved interobserver and intraobserver reliability, but Doornberg and colleagues found the addition of 3-D did not significantly improve reliability .
Computed tomography scans have led surgeons to reclassify fracture patterns and change the plan of treatment for tibial plateau fractures as shown in one study by Chan and associates. Macarini and colleagues reviewed 25 patients with a tibial plateau fracture and compared standard radiography with multiplanar and 3-D CT reconstruction. In 60% of patients, CT features led the orthopaedist to modify the treatment. The authors also noted that compared with axial CT, the 3-D reconstructions enabled a more accurate assessment of plateau depression and overall view of the fracture fragments. Although 3-D imaging may aid in determining fracture location, articular detail is lost because of volume averaging, so critical assessment of 2-D images is important for evaluation of the joint surface. Chan and colleagues reviewed 21 cases of tibial plateau fractures imaged with plain radiography and CT scans. Classification was changed in 12% of the cases with the addition of CT, and the treatment plan was changed an average of 26% of the time. The number of image slices may also be an important consideration. McEnery and colleagues performed an in vitro analysis of sensitivity and specificity of spiral CT and recommended 2-mm sections for optimal sensitivity and specificity.
Special attention must be given to the posteromedial plateau when evaluating CT. Barei and colleagues described the frequency and morphology of the posteromedial fragment on CT in 57 patients with bicondylar tibial plateau fractures. The authors found that the posteromedial fragment was present in 74% of patients and comprised a mean of 58% of the articular surface of the medial tibial plateau and 23% of the entire tibial plateau articular surface. The mean height was 42 mm. Most important perhaps, the mean sagittal fracture angle was 81 degrees. Higgins and colleagues subsequently described the morphology of the posteromedial fragment present on CT scan in 111 bicondylar fractures. They found that the fragment occurred in 59% of cases and on average accounted for 25% of the total joint surface. They found greater than 5 mm of articular displacement in 55% of cases. The posteromedial fragments exhibited vertical fracture patterns, with average sagittal angle of 73 degrees, suggestive of shear instability and vertical displacement. The presence of this fragment has significant clinical implications when deciding on reduction techniques and fixation constructs. Laterally based fixation may fail to adequately stabilize this fragment. Consideration should be given to direct reduction and fixation of this fragment through a posteromedially based approach to ensure adequate fixation.
Magnetic Resonance Imaging
The role of preoperative MRI in tibial plateau fracture management is controversial and evolving. Recent studies suggest the possible importance of MRI in assessing osseous and associated soft tissue lesions. However, neither the natural history of MRI-discovered soft tissue injuries nor the indications for surgical treatment of these injuries in the setting of a tibial plateau fracture has been established. Nonetheless, some authors recommend MRI as an adjunct imaging modality for tibial plateau fractures. It is possible, with further advances in quality and technique, that MRI could supplant CT as the imaging modality of choice if it can be found to consistently provide equivalent detail of osseous injuries.
The limitations of MRI include the difficulty of positioning claustrophobic and obese patients in an MRI scanner. Also, patients with certain implanted metal objects, such as stents or pacemakers, cannot undergo MRI. Additionally, not all spanning external fixators are suitable for MRI scanners according to one study by Kumar and associates. The degree of ferromagnetism was studied in a number of orthopaedic implants including external fixator clamps by measuring the deflection at the portals of a 0.25- and 1.0-T scanner (magnet). Although deflection was found to be significant with some ferromagnetic external fixator clamps, neither heating nor ferromagnetic force was a factor in multiple studied implants. The authors concluded that external fixator clamps exhibiting strong ferromagnetism should be avoided. Consideration should be given to applying titanium external fixator clamps for all spanning fixators to accommodate potential future studies needed by neurosurgeons as well as spine and knee surgeons. The stainless steel Schantz pins used for application of external fixators do not cause thermal problems nor do they displace. In fact, according to Kumar and associates, they are nonmagnetic. Both the orthopaedic and radiology departments must be sufficiently educated about these factors for MRI protocols to be executed without reluctance on the part of the radiology team.
Duplex Ultrasonography and Arteriography
As mentioned earlier, displaced bicondylar tibial plateau fractures and those of the medial condyle carry a significant risk of associated arterial injury. The same is true for fracture-dislocation variants. Because arterial occlusion at the knee level often results in amputation unless perfusion is restored very promptly, a high level of suspicion with rapid definitive assessment is required if limb loss is to be prevented.
It was previously thought that physical examination alone does not reliably identify the presence or absence of arterial injury. However, numerous studies have more recently been published supporting selective arteriography performed only in patients who have abnormal physical examination findings. Ten studies, including two prospective studies, have evaluated the use of selective arteriography in a total of 543 patients with knee dislocation. In each of these studies, physical examination alone was sufficient to detect all clinically significant vascular injuries . If the ABI is considered positive (<0.9), duplex ultrasonography or arteriography should be performed immediately.
Duplex ultrasonography is a fast and accurate examination. It carries no risks. Its effectiveness has been demonstrated in multiple studies ; however, the examination is operator and interpreter dependent and requires the ready availability of a skilled vascular ultrasonographer. The use of arteriography as a primary or routine screening tool for diagnosing arterial injury is cost ineffective, has a poor risk-to-benefit profile, and is therefore unwarranted. In the case of an acutely ischemic leg, if the limb is considered salvageable and the ABI is less than 0.9, formal angiography may be required. Because of the few hours available before significant tissue necrosis occurs, it is essential that a vascular surgeon be involved early in the care of patients with arterial injuries about the knee. Arteriography should never delay vascular consultation and necessary arterial repair and fracture stabilization. If additional information is required by the vascular surgeon to determine if there is a need for formal vascular repair, evaluation with standard or CT angiography can be performed in the radiology suite. However, when the need for revascularization is clear, arteriography should be performed in the OR whenever possible to prevent unnecessary delays in revascularization.
Currently, the most common systems for classifying tibial plateau fractures are the Schatzker classification and the AO/OTA classification systems. Although the Schatzker system may be easier to remember, the AO/OTA comprehensive classification is now commonly used by scientific publications and therefore warrants understanding. The AO/OTA system has also been shown to have a higher interobserver agreement. Additionally, the Hohl-Moore classification can be applied to fracture-dislocation variants that do not “fit” into the Schatzker classification. The Schatzker classification has been found to be superior to the AO/OTA system and the Hohl-Moore classification, although none of the above classification systems have been found to be ideal with regard to interobserver and intraobserver reliability. Although classification of the fracture pattern is emphasized in this chapter, soft tissue considerations are paramount. Soft tissue injury severity is suggested by the amount of comminution and displacement of bone fragments, which reflect the amount of transferred energy. Understanding and properly treating the associated soft tissue injury is at least as important for tibial plateau fractures as for any other fracture type because the soft tissue anatomy is complex, and the thin, vulnerable skin envelope around the knee is also a dependent joint prone to lymphedema. This appreciation of soft tissue injury is of ultimate value in determining surgical approach and timing. The system of Oestern and Tscherne is helpful in classifying the severity of soft tissue injury.
Schatzker’s classification was based on fracture appearance in plain radiographs. The development of CT and MRI significantly improved fracture interpretation by clearly demonstrating the extent of joint surface depression, comminution, and bony displacement.
AO/OTA Comprehensive Long Bone Classification
The AO/OTA classification was published in 1996 and is used for evaluating all long bone fractures, in contradistinction to regionally based classification systems such as the Schatzker classification for tibial plateau fractures. In the AO/OTA classification, the proximal tibia is distinguished by the number 41 (the 4 refers to the tibia, and the 1 refers to the proximal segment, equal in length to the joint line width at the knee). Within each bone segment, the AO/OTA classification divides fractures into three types, denoted as A, B, and C. For articular segments, these three types are (A) extraarticular, (B) partial articular, and (C) complete articular fractures.
Type C fractures typically reflect a higher energy injury than types A and B. Generally, these different types (A, B, and C) reflect ascending complexity in terms of injury nuances and treatment considerations. Type A fractures are extraarticular, which may occur in the metaphysis or epiphysis. Type B fractures involve only a portion of the articular surface. In these fracture patterns, part of the joint surface retains its continuity with the diaphysis. Type B fractures may involve any part of the joint surface or any percentage short of 100%. In addition to less severe injuries, they may represent high-energy injuries as well. Some type B proximal tibial injuries (corresponding with Schatzker type IV) represent fracture-dislocations. Significant displacement or medial plateau involvement indicate these serious injuries. Type C fractures are “complete articular” fractures in which the articular surface is dissociated completely from the diaphysis so that there is no continuity between any articular piece and the diaphysis.
Each of the three fracture types (A, B, and C) is divided into three groups, numbered 1, 2, and 3. Each of the groups is further divided into subgroups, indicated by the decimal notation 0.1, 0.2, and 0.3. The group and subgroup numbers were assigned in order of presumed severity, and they are specifically defined in the AO/OTA classification. Type A fractures are extraarticular. Group A1 is a special category for avulsion fractures: A1.1 denotes avulsions of the proximal fibula, A1.2 of the tibial tubercle, and A1.3, of the intercondylar eminence and cruciate ligament attachments. Group A2 fractures are simple (two-part) metaphyseal fractures. The subgroups are 0.1—oblique in frontal plane, 0.2—oblique in sagittal plane, and 0.3—transverse fractures. Group A3 fractures are multifragmentary fractures that cross the metaphysis. The subgroups of A3 are 0.1—single wedge fragment (which involves only one side of the metaphysis), 0.2—comminuted wedge fragment, and 0.3—complex metaphyseal fracture with a comminuted zone extending all the way across the fractured metaphysis.
The Schatzker classification, first described in 1979, is popular in North America. It combines fracture location and pattern and separately recognizes medial plateau fractures. Schatzker’s types are assigned in presumed increasing order of severity. The attractiveness of this classification system is related to its few types; that its verbal descriptions are familiar, simple, and easy to remember; and that it offers guidance for planning treatment. As a general rule, the Schatzker classification can be divided into low-energy variants (types I–III) and high-energy variants (types IV–VI). Alternatively, this classification can also be divided into unicondylar (types I–IV) and bicondylar (types V and VI). It is worthwhile discussing the characteristics of each of the Schatzker fracture patterns.
Schatzker Type I
Type I is most common in young patients with hard cancellous trabeculae and good bone density, in which case the joint does not crush, but a pure split is created. The fracture line typically occurs in the sagittal plane ( Fig. 62-16 ). For reference purposes, this is a partial articular fracture and is therefore considered a type 41B1.1 fracture in the AO/OTA system.
Schatzker Type II
This fracture is typically associated with either greater energy than a type I or with poor bone quality. This split-depression fracture of the lateral tibial condyle occurs most commonly in the fourth decade of life. In this fracture pattern, the cancellous bone underlying the articular surface cannot withstand the load of the lateral femoral condyle and thus sustains a depressed articular region as well as the split component ( Fig. 62-17 ). For reference purposes, this correlates with the AO/OTA classification type 41B3.1.
Schatzker Type III
Type III fractures are associated with poor bone quality and can be caused by very low-energy mechanisms. This fracture pattern is amenable to the arthroscopically assisted fixation technique described later in this chapter. Type III is a pure depression fracture of the lateral plateau commonly diagnosed in elderly adults and can be considered a fragility fracture. In older patients with osteoporosis in whom the cancellous bone underlying the articular surface is more porous than normal, the bone crushes rather than splits ( Fig. 62-18 ).
In a recent paper by Gardner and colleagues, 103 MRIs on consecutive tibial plateau fractures were performed, and the authors found no true cases of pure depression type III fractures. In every case considered to be a type III fracture by plane radiographs, a peripheral split was noted on MRI. These findings suggest simply that occult fracture lines cannot always be detected on plane radiographs. The clinical significance may therefore be that one should not assume the lateral cortical envelope is stable and will not displace, and thus treatment may need to include lateral cortical support. Schatzker’s classification, based on radiographs, does not seem to be upstaged by these MRI findings, which merely complement our understanding of the pattern. For reference purposes, this fracture correlates to the AO/OTA classification types 41B2.1 and 41B2.2.
Schatzker Type IV
These fractures of the medial condyle may not violate the medial articular surface. They typically pass more laterally, through or lateral to the intercondylar eminence, and separate the medial plateau from the remainder of the tibia. Medial plateau fractures involve higher energy mechanisms and shearing (transverse plane) displacement and are usually unstable. In fact, they represent a variant of knee dislocation. Typically, whereas the MCL and cruciate ligaments stay attached (or partially attached) to the medial condyle, the lateral plateau and shaft displace laterally away from the femur and medial plateau fragment. The fracture may be a pure sagittal split but more commonly is oblique to the frontal plane, with the apex of the fracture occurring posteromedially ( Fig. 62-19 ).
An important clinical implication of medial tibial plateau fractures is their tendency toward subluxation or dislocation. Associated arterial, peroneal nerve, and ligamentous injuries are relatively frequent. They should be seen as quite different from partial articular (type B) fractures involving the lateral plateau, which are usually less unstable and the result of lower energy injuries.
Although medial tibial plateau fractures only account for approximately 10% of all tibial plateau fractures, this is the fracture pattern that has the highest association of injuries to the neurovascular structures and cruciate ligaments. ACL and PCL injuries and bony avulsions are common in Schatzker type IV fractures. Bear in mind that radiographs are static images, which do not reveal the maximal displacement that occurred at the time of injury. Thus, even less displaced medial plateau fractures are at higher risk of neurovascular injury. These fractures also carry an increased risk of compartment syndrome and therefore warrant close observation and critical vascular assessment. Rarely, medial plateau fractures may be stable, but even these may surprise the surgeon with late displacement. For reference purposes, medial tibial plateau fractures correspond to the AO/OTA classification types 41B1.3, 41B2.3, 41B3.2, and 41B3.3.
Schatzker Type V
The type V is a total articular injury that involves wedge fractures of both medial and lateral plateaus. The intercondylar area may remain more or less intact, with the intercondylar fracture line passing through it but usually not crossing the weight-bearing articular surface. Schatzker recognized a typical “inverted-Y” pattern and classified his type V plateau fractures as 41C1.1, 0.2, or 0.3—noncomminuted total articular fractures in which both the medial and lateral condyles are detached from each other and from the underlying metaphysis. Occasionally, the combination may include a split or split-depression fracture of the lateral plateau in addition to a separate medial plateau fracture. Because the cruciate ligaments typically remain attached to the intercondylar eminence and one plateau, there is usually less femorotibial instability and through ligamentotaxis traction often achieves a reasonably congruent reduction, but without surgical stabilization, loading results in distal displacement of the condyles and often with widening of the intercondylar gap. This pattern is unlikely to be associated with a knee dislocation. CT or high-quality traction radiographs may be needed to demonstrate clearly their bicondylar, total articular pattern ( Fig. 62-20 ).
Schatzker Type VI
The Schatzker type VI tibial plateau fracture is a bicondylar fracture that involves both medial and lateral tibial plateaus but has the distinction of having more comminution and obvious complete separation of the articular surface (including the eminence) from the diaphysis ( Fig. 62-21 ). These are usually high-energy injuries commonly associated with severe articular involvement and soft tissue injury. Multifragmentation comminution of at least one plateau is common. Metaphyseal comminution may be extreme and extend into the diaphysis as well. These displaced, comminuted bicondylar proximal tibial fractures typically have severe soft tissue injury, whether they are closed or open. They carry a significant risk of wound slough if operated on early, particularly through extensile midline incisions. This pattern should serve warning for possible compartment syndrome and neurovascular injury, and thus, serial neurologic and vascular assessment should be performed. For reference purposes, these fractures correspond to the AO/OTA classification types 41C2, and 41C3.
This system is applied to fracture-dislocation variants that do not “fit” in the Schatzker system ( Fig. 62-22 ).
Type I: Coronal Split
These fractures account for 37% of tibial plateau fracture-dislocations. The fracture involves the medial side and is apparent on the lateral view. The fracture line is typically in an oblique coronal-transverse plane at a 45-degree angle to the medial plateau. The fracture may extend to the lateral side, and avulsion fractures of the fibular styloid, insertion of the cruciates, and tubercle of Gerdy are common. Capsular disruption and ligamentous injuries are common.
Type II: Entire Condyle
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 eminences. The opposite collateral ligament is involved in half of fractures, resulting in fracture or dislocation of the proximal fibula. This type constitutes 25% of all fracture-dislocations, and 12% result in neurovascular injuries. Stress testing is necessary to determine occult ligament injury.
Type III: Rim Avulsion
Constituting 16% of fracture-dislocations, this type involves almost exclusively the lateral plateau, with avulsion fragments of the capsular attachment, the Gerdy tubercle, or plateau. Disruption of the ACL or PCL is common. Although meniscal injury is rare, neurovascular injuries occur in 30% of fractures. Type III fractures are almost invariably unstable.
Type IV: Rim Compression
This injury accounts for 12% of all fracture-dislocations. Akin to type III fractures, these are almost invariably unstable as well. 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.
Type V: Four Part
Constituting 10% of all fracture-dislocations, this injury is also nearly invariably unstable. Neurovascular injury occurs in 50% of fractures. The popliteal artery and the peroneal nerve are injured in more than one third of cases. Both collateral ligament complexes are typically disrupted with the bicondylar fracture, and the stabilization provided by the cruciates is lost because the intercondylar eminences are separate fragment(s).
This classification is the only mechanistic system currently in use. It is primarily used in Europe.
Chertsey 1: Valgus
Chertsey 2: Varus
Chertsey 3: Axial
Although one study found the Chertsey classification to be significantly more reliable than the Schatzker classification with regard to interobserver reliability and intraobserver reliability, the utility of this classification system with regard to predicting other injuries and assisting with preoperative planning has not been proven.
Posterior Shear Fracture
Recently, Bhattacharyya and colleagues recognized a subset fracture pattern of the medial tibial plateau fracture that includes pure posterior fracture fragments. These posterior shear fractures, with a more or less coronal plane orientation, typically involve anterior subluxation of the anterior plateau and attached tibial shaft, but the posterior plateau fragments remain co-located with the femur posteriorly and distally ( Fig. 62-23 ). This fracture does not fit into Schatzker’s classification, may be bicondylar, or may be a knee dislocation variant. A posterior approach, with fixation applied to the posterior surface of the proximal tibia is recommended for these injuries.
In the past, major intraarticular fractures remained an unsolved problem, and disability in varying degrees after a major intraarticular fracture was considered unavoidable. Charnley recognized in 1961 that anatomic reduction and early motion were desirable in the treatment of intraarticular injuries, but the techniques of surgery and internal fixation available at the time made these objectives of treatment unattainable. Attempts at early motion after internal fixation frequently resulted in pain because of instability, with resultant loss of fixation and varying degrees of malunion or nonunion. Surgery combined with plaster immobilization resulted in even greater stiffness than plaster immobilization alone. The pathophysiology of joint stiffness was poorly understood, and stiffness after surgery was blamed on the added trauma of surgery and the periarticular location of the fixation device. Therefore, surgery was considered the last resort, and nonoperative techniques were generally favored for treatment of articular injuries. The phases of treatment were evaluation, reduction, immobilization, and rehabilitation. Rehabilitation followed fracture union, resulting invariably in joint stiffness. Apley pioneered early joint rehabilitation and developed successful methods of traction that permitted early motion of joints while providing sufficient immobilization for the fracture to unite. He applied these techniques to the treatment of tibial plateau fractures and reported what he considered to be satisfactory results compared with the results of surgery.
The difficulty in evaluating the preceding studies is that the authors reported the results of treatment collectively without analyzing the types of tibial plateau fractures that had satisfactory outcomes. Classification categories such as undisplaced, slightly displaced, and severely displaced, amplified by such terms as vertical or oblique fracture lines split or comminuted, were not helpful for separating fracture types with intrinsically different prognoses. Furthermore, these authors compared the results of the best nonoperative treatment with those of surgical treatment methods that would be considered unacceptable by current standards.
The development by the AO group of atraumatic techniques of open reduction and stable fixation; of new techniques and principles of internal fixation that permitted absolute stability of fixation and early motion without fear of displacement, malunion, or nonunion; and of new implants and instruments that facilitated the attainment of the new goals of ORIF brought about a revolution in fracture surgery. However, as the severity of the skeletal injury increases, so does the concomitant injury to the soft tissue envelope. As surgical treatment became increasingly popular, high-energy fracture types (Schatzker types IV, V, and VI) were often managed with large extensile approaches and internal fixation hardware. The usually lengthy operation and surgical approach through a tenuous soft tissue envelope, combined with the use of multiple implants, led to complication rates as high as 50% in some studies.
For these more complex injuries, contemporary surgical techniques have evolved to include concepts such as indirect reduction, antiglide fixation, and composite fixation, as advocated by Mast and colleagues. Newer devices such as cannulated screws, monolateral external fixators, anatomic periarticular plates, and external fixation techniques based on circular Ilizarov-type fixators with tensioned small wires have been used in concert with limited surgical approaches (guided by CT and careful preoperative planning) to achieve excellent results with fewer surgical complications.
Early attempts at internal fixation were fraught with complications. These occurred in large part because poorly timed surgical approaches abused the tenuous soft tissue envelope of a fractured knee because traumatic extensile approaches were used too soon after injury. Temporary use of knee-spanning external fixators was unusual, and minimally invasive surgical strategies had not been developed. Wound dehiscence and infection too frequently developed, giving open reduction a bad name.
The concept of staged fixation has now gained favor. When the soft tissues are significantly compromised, immediate exposure for internal stable fixation is risky. Overall limb realignment and stabilization, important for soft tissue healing, can be achieved with an external fixator that initially spans the zone of injury. For tibial plateau fractures, these typically extend from the femoral shaft to the tibial shaft. If the plateau fracture is open, the wound may provide adequate access for anatomic reduction and secure fixation of the articular surface. However, further exposure for internal fixation may increase the risk of wound slough unacceptably, especially if done during the first days after injury. If the initial fracture is not open, it may be safest to delay the entire open reduction and fixation procedure until the soft tissue envelope has recovered enough to tolerate exposure adequate for articular reduction and the chosen means of fixation. During this period of soft tissue recovery, external fixation is available to splint the fracture and its surrounding soft tissues as well as maintain a general ligamentotaxis reduction of the major metaphyseal and diaphyseal fracture fragments. When the soft tissues have recovered sufficiently to allow a secondary procedure, delayed fixation can be accomplished through a safe operative corridor of healthy soft tissues.
Emergent and Urgent Stabilization
Tibial plateau fractures are not emergencies unless they are open or associated with a knee dislocation, compartment syndrome, or vascular lesion. An external fixator that spans the knee joint provides immediate temporary stability. Urgent external fixation should be considered for any patient with a grossly unstable proximal tibia fracture or a significant closed soft tissue injury, especially whenever definitive skeletal stabilization must be deferred. If the knee region is rather stable, with hypermobility in a single plane, and less significant soft tissue damage, a splint may provide quite satisfactory temporary support, and in such cases, temporary external fixation should not be applied. External casts and splints cannot really stabilize significant injuries about the knee, particularly in large, muscular, or obese patients. Traction, by adding tensile forces to the remaining intact ligaments and other soft tissues that cross the knee, usually improves alignment and stability, but the amount of force needed requires the use of skeletal traction. Also necessary is additional excellent external support for the lower extremity, such as offered by a well-constructed balanced suspension. However, this type of immobilization cannot be maintained well when a patient must be moved or repositioned.
Temporary external fixation offers the best available immobilization for a significant tibial plateau fracture, although its stability is usually compromised by the injury itself and is thus not equivalent to definitive internal or external fixation. However, if properly applied, it stabilizes the injured area well, maintains some traction, provides stability through soft tissue tension, improves quality and usefulness of imaging studies, and avoids gross motion and redislocation. Compared with the alternatives, it provides a vastly better environment for soft tissue recovery and wound care. It facilitates patient care and patient transportation within and between institutions. Most importantly, it has been found that a staged protocol involving temporary spanning external fixation before formal definitive fixation for high-energy tibial plateau fractures is associated with low rates of deep infection and nonunion after conversion to definitive fixation. For these reasons, we strongly advocate for the routine use of temporizing external fixation in high-energy, unstable variants and those with significant soft tissue injuries.
Vascular injury is rarely seen in most tibial plateau fractures. However, fracture-dislocations, medial plateau fractures (Schatzker type IV), and high-energy bicondylar fractures (Schatzker type IV and VI) do present a risk to the vascular structures, specifically the popliteal artery and trifurcation. In these cases, application of a knee-spanning external fixator is indicated to provide stability and protect the vascular repair. Debate centers on whether the fixator should be applied first, after temporary shunt placement, or after definitive vascular repair because anecdotal concern exists regarding the risk of disruption of the vascular repair during manipulation of the extremity after arterial repair. If an arterial repair is required, a bridging external fixator should ideally be applied rapidly first to restore length and stability, thereby aiding the vascular surgeon. One of the most common and preventable mistakes is to repair the vessel with the fracture in a displaced position before external fixation, leading to inadequate “slack” being left in the vascular repair to allow restoration of length and alignment after repair. Alternatively, a femoral distractor can be used to bring the fracture out to length and provide enough stability to facilitate temporary shunting or definitive arterial repair. Because most vascular surgeons use a rather extensive posteromedial exposure, we do not recommend further metaphyseal reconstruction until the vascular access wound has healed. In many circumstances, fasciotomies should accompany the vascular repair. Calf fasciotomies should be done whenever the warm ischemia time exceeds 4 hours or other factors suggest risk of reperfusion-related compartment syndrome.
Patients who present with open injuries should be carefully evaluated for the location and severity of the open wound. An open fracture of the tibial plateau is surgically urgent representing special problems in management. It must be thoroughly débrided and stabilized to prevent infection. Adjunctive intravenous antibiotics and appropriate tetanus prophylaxis are required. The decision about how best to provide the desired stability usually presents the most difficult problem.
After initial irrigation and débridement and external fixation, the patient should be returned to surgery within 48 hours for a second assessment of the wound and débridement if needed. When a healthy wound has been established, delayed primary closure, or other procedures if required, should accomplish wound closure within 5 to 7 days.
Occasionally, if adequate débridement can be accomplished, the fracture pattern is amenable, and the open wound coincides with the planned location of fixation hardware, after thorough irrigation and débridement, fixation of the articular portion of the fracture can be carried out at the time of presentation. However, this should be done with the least possible additional dissection and soft tissue trauma. The smallest amount of hardware consistent with stable fracture fixation should be chosen. Usually, it is limited to lag screws.
Immediate internal fixation for open fractures is not typically indicated in open tibial plateau fractures. The risk-to-benefit ratio must be carefully assessed when contemplating primary internal fixation. Internal fixation for open fractures has been shown to be beneficial in patients with multiple injuries, massive or mutilating limb injuries, open fractures with vascular injuries, and open intraarticular fractures. * Rotational or free flap coverage of the joint and soft tissue defect should be undertaken as soon as a healthy wound tissue is achieved. An appropriate goal is to obtain soft tissue coverage within the first 5 to 7 days. When the soft tissue envelope has healed sufficiently and the wound appears free of infection, reconstruction of the metaphyseal–diaphyseal bone defect may be addressed. For patients who have had rotational or free vascularized flap procedures, this reconstruction should typically be delayed 4 to 6 weeks after definitive wound coverage. At that time, the flap can usually be elevated in a manner that avoids or protects its vascular pedicle, and plate fixation can be applied, with simultaneous bone grafting for bone defects in these selected fractures. However, we recommend that metaphyseal or diametaphyseal bone grafting be performed on a delayed basis after complete wound healing has been achieved.
* References .
If additional fasciotomy incisions are required or if the surgical incision would create large underlying flaps in conjunction with the open wound, a staged procedure is indicated. Thorough irrigation plus débridement of the fracture and traumatic wounds remains the single most important step in the prevention of infection. Repeated débridement may be necessary. Especially for severe injuries, reassessment of the wound in the OR is advisable within 48 hours of the initial débridement. Although administration of perioperative antibiotics is routine for each such débridement procedure, the duration of coverage remains debatable. Brief use of systemic antibiotics, perhaps supplemented with local delivery systems such as the tobramycin–polymethyl methacrylate bead pouch dressing described by Henry and colleagues, reduces the risk of superinfection. The surgeon should give consideration to planned future incisions when performing fasciotomies in the setting of tibial plateau fractures. Both one- and two-incision fasciotomy surgical techniques have been shown to be effective when properly performed.
Restoration of length, alignment, and rotation is easier if performed early. The principles and techniques of ligamentotaxis are much more easily accomplished in the acute setting. This rapid application of temporizing external fixation in polytraumatized patients also minimizes the extent of continued systemic physiologic insult caused by continued fracture instability and extensive open surgical procedures. If surgical reduction is delayed, it is mandatory that the fracture be maintained in a reduced or distracted position; this is a basic principle when treating these injuries in multiply injured patients.
Although skeletal traction can maintain proximal tibial fracture alignment, it is an unacceptable form of treatment for polytrauma patients because it enforces a recumbent position, interfering with patient care, transport, and pulmonary and gastrointestinal function. Too often, multiply injured patients develop problems that delay definitive fixation and result in a longer than anticipated period of bed rest in skeletal traction. To reduce the risk of complications related to recumbency during temporary stabilization and distraction of the tibial plateau fracture, we favor a bridging external fixator that spans the knee.
A variety of external fixators have been proposed for the treatment of tibial plateau fractures. There are two different major roles for this treatment modality. First is the use of provisional, joint-bridging external fixation for temporary stabilization of a severe knee injury. The second is the use of external fixation as a part of the definitive fixation for a proximal tibial fracture, usually in company with open reduction and interfragmentary screw fixation for displaced fractures that involve the articular surface. Definitive treatment that includes external fixation is discussed in the section Definitive External Fixation.
Two 5- or 6-mm threaded half-pins with a mechanically stable connecting rod are placed into the femur, with a similar pair in the tibia. Stainless steel pins are stiffer. Hydroxyapatite coating is unnecessary if the fixator will only be used for days to a few weeks. If plans include conversion to definitive external fixation, hydroxyapatite pins are useful. Each pair of pins should be spread apart to improve stability but if possible kept out of the fracture site and the path of future surgical incisions. The simplest stable connection that can be made with available frame components is used to bridge the knee. The use of radiolucent connecting rods and placement of metal clamps away from the knee and fracture zone improves imaging ( Fig. 62-24 ). Traction and realignment are achieved manually, and the frame clamps are tightened. Usually, no attempt is made to reduce articular fracture fragments or to fix them, although occasionally this might be considered as part of preliminary reduction when the fixator is used for stabilizing an open proximal tibial plateau fracture. After applying sterile dressings with antibiotic medication if desired, alignment and stability are confirmed. We usually apply a lightly compressive dressing, typically including a well-padded prefabricated posterior splint to offload the heel. Maintaining the foot in a plantigrade position is important to avoid equinus contractures. Alternatively, a “kickstand” can be constructed as part of the external fixator to offload soft tissue injuries or the heel.
Because of an anecdotal fear of infection, it has classically been taught that all temporary external fixation pins should be placed out of the zone planned for definitive internal fixation. Laible and colleagues sought to determine whether overlap between temporary external fixator pins and definitive plate fixation correlated with infection in high-energy tibial plateau fractures. They performed a retrospective review of 79 patients with unilateral high-energy tibial plateau fractures treated initially with knee-spanning external fixation followed by delayed internal fixation. The authors found no significant difference in rate of infection in patients whose pin sites overlapped with the definitive internal fixation compared with those whose pin sites did not overlap. The authors stated that fears of contamination and infection from overlapping pin sites do not appear to be clinically grounded. We continue to advocate for placement of pins out of the zone of planned future internal fixation whenever possible because there is little to lose with this approach. However, when required to provide adequate reduction and stability to fracture fragments and more important stability to soft tissues, we agree that pin placement should be performed wherever it is required, regardless of plans for future surgery.
Indications for Operative Management
The goals of treatment for any intraarticular fracture are to preserve joint mobility, joint stability, articular surface congruence, and axial alignment. Additional goals are to provide freedom from pain and to prevent posttraumatic osteoarthritis.
Most investigators would agree that four primary factors ultimately contribute to the prognosis of proximal plateau injuries: (1) the degree of articular depression, (2) the extent and separation of the condylar fracture lines, (3) the degree of diaphyseal–metaphyseal comminution and dissociation, and (4) the integrity of the soft tissue envelope. When considering operative treatment, all four of these factors must be evaluated to determine the best course of treatment.
Absolute indications for surgery are (1) an open tibial plateau fracture and (2) a tibial plateau fracture combined with an acute compartment syndrome or an acute arterial injury.
Relative indications for surgical fixation include (1) displaced bicondylar fractures, (2) displaced medial condylar fractures, (3) lateral plateau fractures that result in joint instability, and (4) plateau fractures in the context of a multiply injured patient. The primary contraindications to immediate formal ORIF are a compromised soft tissue envelope with either an open or a closed fracture, compartment syndrome, and vascular injury.
Joint depression and articular defects resulting from impacted articular fragments remain as permanent joint defects. These defects, when examined at the time of late articular reconstructions, have never been found to be filled with fibrocartilage, which would have restored stability. Therefore, any joint that is unstable as a result of joint depression or displacement remains unstable unless the depression or displacement is corrected surgically. Articular reduction is best done in the acute setting. Late intraarticular osteotomy is a complex procedure with many potential complications, especially when performed in the presence of significant joint stiffness.
A distinction should be made between the degree of osseous depression of the articular joint surface (i.e., true joint depression) and the translational or axial displacement of an entire fractured condyle, as may be seen with a severely displaced lateral condyle. This displacement may occur without any joint impaction or compression. Joint instability can result from articular depression, condylar displacement, or rupture of collateral and cruciate ligaments. There is no universal agreement on the amount of articular depression that can be accepted; ranges from 4 to 10 mm have been described as tolerable. *
* References .Long-term studies (>20 years’ follow-up) indicate a lack of correlation between residual osseous depression of the joint surface and the development of arthrosis. However, joint deformity or depression that is significant enough to produce joint instability or dynamic alteration of the mechanical axis is predictive of a poor result. † It is well accepted that a depressed portion of intraarticular surface cannot be reduced by traction alone; these surfaces must be surgically elevated and supported with bone graft.
† References .Pauwels demonstrated that if the degree of stress (force per unit area) that results from weight bearing exceeds the ability of articular cartilage to regenerate or repair itself, articular cartilage degeneration ensues, leading to posttraumatic osteoarthritis. Displacement of articular fragments results in a decrease of the available surface area of contact and therefore in increased stress even in the presence of a normal load and normal direction of load application. There are, however, no accurate data on the amount (area) of articular displacement and depression that leads to degenerative joint disease.
Mechanical studies have indicated that statistically significant elevation of contact pressures occurs in a joint when the articular step-off or incongruence is greater than 3 mm. An incongruence of less than 1.5 mm appears to result in no significant increase in contact pressures. Therefore, the joint may have some ability to compensate for a limited degree of joint depression. However, if there is an associated axial malalignment during weight bearing, the rise in stress is more significant.
Mitchell and Shepard, in their studies of the effects of articular malreduction and unstable fixation on the outcome of articular fractures, showed that accurate reduction and stable fixation of intraarticular fragments are necessary for articular cartilage regeneration and that malreduction and instability result in rapid articular cartilage degeneration. These findings not only support the need for an anatomic reduction of the joint but also emphasize the need for stable fixation to enhance articular cartilage regeneration. Stable fixation also facilitates early motion by relieving pain, which is often the result of instability and motion at the fracture site.
Axial Malalignment and Instability.
A factor in the long-term prognosis for these injuries is the ability to maintain the normal relations of the femoral condyles on the plateau surfaces. It is crucial not to develop a contact pressure overload on either of the condyles. Rasmussen showed a high correlation between posttraumatic osteoarthrosis and residual condylar widening or discontinuity between the tibial plateau surfaces and the femoral condyles. Lansinger and colleagues later reviewed the same cohort of patients and found good to excellent results in 90% of the patients with stable knees at 20 years’ follow-up. The investigators concluded that knee stability rather than residual displacement was the main indication for surgery and a good long-term result. Thus, with certain high-energy fracture patterns, anatomic joint reconstruction may be impossible to achieve, but this does not necessarily preclude a reasonable functional outcome, provided the metaphyseal and diaphyseal components that are still under the surgeon’s control are maintained in such a way as to maintain the overall mechanical axis. This concept is the basis for a less invasive approach when treating some selected high-energy fracture patterns in which the joint surface is severely traumatized or when the patient cannot undergo a significant surgical procedure.
Large fracture gaps may also contribute to knee instability resulting from a malreduced and longitudinally displaced condyle. Malalignment of the condyles in relation to the tibial shaft with subsequent shift of the mechanical axis is another prominent factor in the outcome for these patients. The radiographic appearance of osteoarthrosis and degenerative joint disease does not always correlate with the clinical picture ; however, Kettelkamp and colleagues suggested that the maintenance of the correct mechanical axis at the knee is a major factor in determining functional outcome and in the prevention of osteoarthrosis. Two factors, a decrease in joint surface area and a rise in stress resulting from the deformity and the increase in axial loading, may lead to posttraumatic osteoarthrosis. The likelihood of osteoarthrosis is greatly increased if these two factors are coupled with instability, which can result from either joint depression and incongruity or an associated ligament rupture.
Regardless of treatment method chosen, one must ensure that there are adequate joint congruity, stability, and axial alignment. In certain complex fractures, such as the Schatzker type VI injury, the zone of comminution at the diaphyseal–metaphyseal junction may hinder the surgeon’s ability to reconstruct the appropriate mechanical axis. Internal fixation must span this area, and additional bone grafts may be required. Such fractures typically have significant associated soft tissue injury, and internal fixation may not be safe to apply initially, as discussed previously.
Newer techniques for reconstructive procedures (i.e., fresh allograft plateau transplantation, resurfacing hemiarthroplasty, and total-knee replacement) all depend on correct maintenance of the mechanical axis. Because of this, the initial fracture treatment should restore and maintain alignment so as not to compromise secondary reconstruction.
From these observations, we offer the following principles of treatment of tibial plateau fractures:
Maximal joint congruity can be restored only by open reduction.
Any tibial plateau fracture that results in joint instability requires ORIF.
Stable fixation of articular fragments and anatomic reduction are necessary for optimum joint preservation and early range of motion.
If an open reduction is indicated but is inadvisable because of patient-related or injury factors or because the complexity of the injury exceeds the ability of the treating team, the fracture may be treated with skeletal traction and early motion. Alternatively, if formal fixation is contraindicated, early fixation of the articular portion of the injury is recommended if possible. After injury factors have been resolved, delayed metaphyseal reconstruction is possible.
These relative indications are general. When treating a particular patient, the surgeon must be governed not only by joint congruity, joint stability, and axial alignment but also by what we call the “personality” of the fracture, which is a synthesis of patient-related factors, injury factors, ability of the treating team, and suitability of the hospital environment, as discussed in the next section.
Personality of the Injury.
If the fracture is displaced and unstable, joint congruity, axial alignment, and stability are most likely restorable only by ORIF. Whether such a course is to be pursued must be worked out carefully, however. The decision is best made by defining the personality of the injury.
First, the patient-related factors must be considered; these include age, previous medical history, occupation and leisure activities, and expectations of treatment results. For example, the goals of treatment are quite different for an osteoporotic octogenarian than for a healthy young athlete.
Second are the injury factors. Here the surgeon must define carefully the injury to the soft tissue envelope, taking into consideration the location of the fracture and the condition of the skin in and around the proposed surgical exposure if surgery is contemplated. The open or closed nature of the fracture, the associated soft tissue and bone injuries, and the possibility of a concomitant neurologic or vascular deficit or an acute compartment syndrome must be determined. Next, the characteristics of the fracture itself must be defined with great care in order to classify it. Information regarding the depth of articular impaction, degree of condylar displacement, and amount of fracture line extension from the metaphysis into the diaphyseal region must be obtained from the plain radiographs, traction radiographs, and traction CT scans. The degree of osteoporosis must be determined because the quality of bone is of paramount importance in judging the operability of the fracture. With this insight, the surgeon is able to formulate a preoperative surgical plan that helps define the surgical tactic and outlines the expected difficulties of treatment. Ultimately, the same information manifests in the patient’s prognosis.
Third, the surgeon must evaluate the treatment team and the treatment environment. For many complex tibial plateau fractures, the surgical treatment is difficult and complex. Such injuries are best managed by persons with experience in complex intraarticular injuries. This area may be the most difficult to assess because it forces the surgeon to evaluate objectively his or her own skills and those of the surgical assistants as well as the adequacy of the treatment environment. For complex injuries, complete sets of large and small plates and screws, including anatomic periarticular plates, large articular reduction forceps, femoral distractors, and in some circumstances various external fixation devices, should be available. In addition, the treatment team should include skilled nursing and physiotherapy staff with experience in the treatment of these patients.
Nonoperative treatment is indicated for many tibial plateau fractures. Some fractures that occur after a low-energy injury are incomplete or nondisplaced. Other injuries that may be treated successfully in a nonoperative fashion include a displaced lateral plateau fracture without articular instability and some unstable lateral plateau fractures in osteoporotic patients. Another relative indication for nonoperative treatment is the presence of significant cardiovascular, pulmonary, neurologic, or metabolic compromise (e.g., severe diabetes with occlusive vascular disease or significant venous stasis ulceration).
Nonoperative treatment of these injuries does require early motion and subsequent prevention of displacement. Schatzker and McBroom found that patients with tibial plateau fractures treated nonoperatively in a plaster cast for 1 month or longer experienced marked stiffness of the knee. In most instances, fracture displacement is prevented by restricting weight bearing, and stiffness is prevented by instituting early controlled motion in a hinged knee fracture brace. Depending on fracture stability, the knee may be locked in full extension for 1 to 2 weeks, after which the hinges are adjusted to begin a gradual increase in range of motion. Frequent clinical and radiographic follow-up is required early in the course of treatment to guard against unrecognized loss of metaphyseal reduction. The goal is to achieve at least 90 degrees of flexion by 4 weeks after injury. Unlimited motion may be encouraged from the outset for stable fractures. Weight bearing is delayed until there is radiographic appearance of early fracture line consolidation. Usually, by 6 to 8 weeks the patient has progressed to 50% partial weight bearing, and by 12 weeks, the patient is allowed to ambulate with full weight bearing.
A fracture is considered stable if it does not exhibit, on varus or valgus stressing, any more than 10 degrees of instability at any point in the arc of motion, from full extension to 90 degrees of flexion. The degree of instability that is acceptable within this range must also be viewed in terms of the personality of the injury. In evaluating a partial articular fracture for stability, it must be remembered that a peripheral wedge fragment, if it involves the posterior part of the plateau, does not contribute to instability in the frontal plane, and the joint may appear to be perfectly stable on varus and valgus stressing. However, the fragment does create instability in the sagittal plane and is an absolute indication for surgical reduction and stabilization. Because small degrees of malalignment and instability may have adverse long-term effects on the knee joint, no more than 10 degrees of instability in the frontal plane should be accepted. If more than 10 degrees of instability is noted on stressing, the fracture is deemed unstable ( Fig. 62-25 ).
If the fracture is unstable but is not suited for ORIF because of excessive comminution, advanced osteoporosis, or other patient-related factors or if it is decided that the fracture should be treated openly but the treatment must be delayed, the patient may be treated with skeletal traction and early motion. As long as joint mobility is preserved, secondary reconstructive joint salvage procedures such as intraarticular osteotomies are possible. These procedures are usually much less successful in the presence of joint stiffness.
When skeletal traction is used for comminuted or unstable fractures, a distal supramalleolar tibial pin should be inserted. Ten to 15 lb of traction usually reduces the condylar fragments by ligamentotaxis. As stated previously, however, impacted articular fragments are not reduced with manipulation or traction alone because there are no soft tissue attachments with which to pull them upward. If skeletal traction has been used, a Thomas splint and Pierson knee attachment can often be used to initiate early active knee flexion. A radiograph should be obtained with the leg out of traction at 4 to 6 weeks after the injury to see whether there is any subsequent displacement. If the fracture shows early signs of union or reveals no further displacement, the traction pin can be removed, and a fracture brace or hinged knee brace should be placed at this time. With this method of treatment, the patient should remain strictly without weight bearing for at least 12 weeks, after which progressive weight bearing is allowed as healing is determined radiographically.
Many investigators have identified the most common fracture pattern in the elderly population as the split depression (Schatzker type II). In general, these and other low-energy fracture patterns maintain their overall reduction * when treated with a short period of traction followed by fracture brace application. The fracture patterns that have been shown to lose their reduction when treated in a conservative fashion include type 4 (medial condyle) fractures and those (type 6) with diaphyseal dissociation. The results of nonoperative treatment of displaced tibial plateau fractures in the elderly population are usually mediocre.
* References .
Definitive surgical repair of displaced tibial plateau fractures has evolved significantly over the past two decades. The goals are to repair the knee by restoring its anatomy to as nearly normal status as possible while avoiding the potential complications of injury and treatment. Atraumatic reduction, absolutely stable articular fragment fixation, metaphyseal repair (although possibly with indirect reduction and relative stability), early motion, and progressive rehabilitation as fracture fixation and healing permit are the essential goals. Our understanding of normal anatomy has improved and can be applied intraoperatively to assess and guide the surgeon’s progress with repair. High-quality image intensification fluoroscopy with precise positioning is necessary for this. Complications of surgery, particularly related to wound slough, can be made less frequent by delaying definitive repair or using compromise approaches that avoid badly injured tissue while perhaps accepting a less than perfect reduction. Not only is reassembly of the joint surface important, but restoration of the lower extremity mechanical axis is key to treatment of this injury. The latter can be accomplished without extensive surgical approaches.
Arthroscopy has been applied successfully to certain tibial plateau fractures. It permits assessment and treatment of intraarticular soft tissue and joint surface injuries. Fluoroscopy is usually required as well, and open, but perhaps less extensive, incisions might be needed to provide stable fixation after an arthroscopically assisted reduction.
External fixation can be an effective alternative to internal fixation for some tibial plateau fractures. However, it must be used with understanding and care. By itself, external fixation does not reduce comminuted or depressed articular fragments, which need direct visualization and reduction. Only limited interfragmentary compression is possible without supplementary internal fixation. Stability may be inadequate unless a properly designed and applied external fixator is used. Pin tract infections, which may involve the fracture site or knee (or both), are possible, particularly when the fixator is placed close to the joint and into comminuted areas for optimal fracture stability. Patients sometimes have difficulty tolerating external fixators. However, these devices do not require significant soft tissue exposure and can provide excellent fixation to achieve fracture healing with satisfactory alignment, particularly with regard to limb axis. In combination with well-executed internal fixation, external fixation may be part of a combination treatment that reduces the frequency of wound healing problems while achieving the desired goals of fracture repair. However, unless a patient has severe soft tissue injury or local resources and expertise have developed strongly in the direction of external fixation instead of modern internal fixation, the latter is typically selected for most tibial plateau fractures. External fixation, as just mentioned, may be invaluable for temporary use while a patient’s soft tissues recover before internal fixation or while he or she is transferred to an appropriate center for definitive care.
The challenge for the surgeon is to assess the patient and the patient’s injuries, considering the possible treatment modalities, and to develop and execute an appropriate care plan that takes into account the patient’s circumstances, injury, and available resources.
Tibial plateau fractures are complex injuries that involve both bone and soft tissue. Relevant anatomy must therefore be thoroughly understood from both a skeletal and a soft tissue standpoint. A discussion of the most relevant cartilage, ligamentous, and bony anatomy in this section is followed by clinical applications of surgical anatomy in the sections thereafter.
The tibial plateau refers to the proximal end of the tibia, including the metaphyseal and epiphyseal regions as well as the articular surfaces made up of hyaline cartilage. Following the AO/OTA classification, the tibial plateau includes the metaphysis to a distal distance equal to the width of the proximal tibia at the joint line. The proximal tibia is divided into medial and lateral plateaus as well as the tibial eminence. This tibial eminence is further divided into prominent medial and lateral tibial spines, adjacent to which attach the ACL and PCL as well as medial and lateral menisci ( Fig. 62-26 ).
The fibular head lies along the posterolateral border of the lateral tibial plateau and articulates with the tibia at the proximal tibiofibular joint, which begins just distal to the knee joint line. The fibular head serves as the attachment for several important knee posterolateral corner stabilizers, including the fibular collateral ligament, PFL, and biceps femoris tendon. The Gerdy tubercle is found on the anterolateral aspect of the proximal tibia and serves as the distal insertion site for the iliotibial band. The tibial tubercle serves as the main attachment site for the patellar tendon, which has a broad flat insertion of approximately 3 cm in width.
One of the most important anatomic distinctions related to the proximal end of the tibia is the size and shape of the medial and lateral condyle. The medial condyle with its articular surface has a slightly concave shape and is larger in both length and width than the lateral condyle, which has an articular surface slightly convex in shape. Understanding the size and shape differences between the two condyles aids interpretation of radiographic landmarks and knee pathology.
Another important anatomic distinction is the difference in height of the lateral and medial condyles. The lateral tibial plateau lies approximately 2 to 3 mm superior (proximal) to the medial plateau. There is a slight varus alignment of the proximal tibia (medial proximal tibial angle, 87 degrees [range, 85–90 degrees]). Understanding the difference between medial and lateral plateau heights is critical for reestablishing normal alignment and height to the fractured or malaligned proximal tibia.
The lateral epicondyle of the femur lines up with the lateral rim of the tibial plateau, and the medial epicondyle with the medial rim of the tibial plateau. Although restoration of the normal intercondylar width may be difficult during repair of some tibial plateau fractures, it is important for recreating normal contact pressures between the distal end of the femur and proximal end of the tibia.
It is also important to recognize that the proximal end of the tibia has a posterior slope of approximately 9 degrees (posterior proximal tibial angle, 81 degrees [range, 77–84 degrees]). Variability in posterior slope as well as other anatomic variables of the tibial plateau anatomy can be inferred from opposite knee radiographs when attempting to assess pathology or postreduction accuracy. These radiographs of the opposite, normal proximal tibia are thus valuable for proper preoperative planning. In the case of bilateral injuries, the surgeon must occasionally revert to use of the normal values mentioned earlier while attempting to achieve similar alignment and a neutral mechanical axis for both lower extremities.
Soft Tissue Anatomy
Cartilage and Menisci.
Both medial and lateral plateaus are covered by hyaline articular cartilage. The lateral plateau cartilage is slighter thicker (4 mm) than the medial plateau cartilage (3 mm). The anatomy of the medial and lateral menisci differ quite significantly as well ( Fig. 62-27 ).