You are in: eMedicine Specialties > Radiology > MUSCULOSKELETAL Tibial Plateau FracturesArticle Last Updated: Jan 24, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 11
  Author: Steven M Sorenson, MD, Consulting Staff, Department of Radiology, Coast Radiology Imaging and Intervention Steven M Sorenson is a member of the following medical societies: Radiological Society of North America Coauthor(s): Amilcare Gentili, MD, Clinical Professor of Radiology, University of California at San Diego; Consulting Staff, Department of Radiology, Thornton Hospital; Sulabha Masih, MD, Associate Professor of Diagnostic Radiology, University of California at Los Angeles; Consulting Staff, Department of Radiology, Section of Musculoskeletal Radiology, West Los Angeles Veterans Affairs Medical Center Editors: Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; William R Reinus, MD, MBA, FACR, Professor of Radiology, Temple University; Chief of Musculoskeletal and Trauma Radiology, Vice Chair, Department of Radiology, Temple University Hospital; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Felix S Chew, MD, MBA, EdM, Professor, Department of Radiology, Vice Chairman for Radiology Informatics, Section Head of Musculoskeletal Radiology, University of Washington Author and Editor Disclosure Synonyms and related keywords: bumper fracture, fender fracture, tibial fracture, broken leg, tibia fracture INTRODUCTIONSection 2 of 11
  BackgroundAlthough tibial plateau fracture was originally termed a bumper or fender fracture, only 25% of tibial plateau fractures result from impact with automobile bumpers. The most common mechanism of injury involves axial loading, such as results from a fall. Other patterns of injury result from laterally directed forces or from a twisting injury. In all cases, force is directed from the femoral condyles onto the medial and lateral portions of the tibial plateau, resulting in fracture. In younger patients, the most common pattern of fracture is splitting, while in older, more osteoporotic patients, depression fractures typically are sustained. Soft tissue injuries (eg, to cruciate and collateral ligaments) occur in approximately 10% of patients. In particular, medial plateau injuries may result in fracture of the fibular head, which may injure the peroneal nerve or may be associated with popliteal artery occlusion. Patients may present with a knee effusion, pain, and joint stiffness. Finally, although severe fractures often are repaired surgically, both operatively and nonoperatively treated fractures are at risk of developing posttraumatic osteoarthritis as a result of ligamentous injuries with resultant instability as well as articular discongruities, biomechanical alteration of normal compressive forces, and cartilage damage. PathophysiologyVarus stresses tend to be less common than valgus stresses due to the inherent valgus carrying angle of the knee and protection by the opposite extremity. Coupled with the fact that the medial plateau of the tibia is stronger than the lateral, fractures of the lateral plateau are much more common than the medial. To injure the medial plateau requires a large amount of force, and fractures of the medial plateau usually are seen in conjunction with fractures of the lateral plateau and other bones about the knee joint, as well as the supporting structures. In particular, forces that result in fractures of the lateral plateau (75-80% of fractures) are directed medially and also may result in disruption of the anterior cruciate ligament or the medial collateral ligament. Since laterally directed forces that cause medial plateau injuries (5-10% of fractures) tend to be much more violent, additional soft tissue structures tend to be injured, including the posterior cruciate ligament, popliteal artery, or lateral stabilization complex of the knee. Pure axial injuries may result in a blend of these soft tissue injuries. Only 5-10% of proximal tibia fractures involve the simultaneous fracture of the medial and lateral plateaus and may result in a combination of soft tissue injuries, depending on the nature of the complex and the severity of forces required to injure both sides of the tibial plateau. FrequencyUnited StatesThe incidence of tibial plateau fractures is unknown. Millions of fractures occur in the United States each year. Of these, approximately 1% are estimated to involve the tibial plateau. InternationalThe international incidence of this fracture is unknown. Fractures of the tibial plateau are estimated to comprise approximately 1% of all fractures. Mortality/MorbidityFractures of the tibial plateau commonly occur in conjunction with other injuries resulting from a fall or motor vehicle accident. Isolated fractures of the tibia are not fatal but may be associated with injuries to nearby structures, including the popliteal artery, ligaments, peroneal nerve, soft tissues, and menisci. The goal of therapy is to reduce the fracture and begin early mobilization. If the patient is immobilized for a lengthy period (>3 wk), the joint will not return to full range of motion. Depression of a tibial plateau that is inadequately corrected results in a varus or valgus deformity and accelerated osteoarthritis. Unappreciated ligamentous injury causes greater than normal stress on the remaining support structures of the joint, malalignment, and the development of premature osteoarthritis. As a result of bony fragmentation and depression at the tibial plateau, along with forces applied at the time of injury by the femoral condyles, the menisci are prone particularly to injury, and they often detach. Collateral and cruciate ligaments may be damaged by this mechanism as well. Occasionally, the tibial tubercle may avulse. In particular, fractures of the medial tibial plateau are associated with greater force, more osseous damage, and more injuries to associated knee structures. Dislocation-relocation injuries are more common with medial plateau injuries than with lateral plateau injuries. With this pattern, the peroneal nerve may be sheared, and the intima of the popliteal artery may be disrupted. The latter may thrombose, or a dissection may develop. However, it is uncommon for this intimal injury to result in life-threatening hemorrhage. Skin injury to the proximal leg is common with tibial plateau fractures. As a result of the superficial location of the cortex of the anterior tibia, loss of skin coverage may result in osteomyelitis or necrosis. The skin may become infected. Finally, complex injuries to the knee often involve the tibial diaphysis. With extensive injuries, extensive edema and, possibly, hemorrhage are seen within the fascial compartments of the leg. This may result in an acute compartment syndrome, with resultant compounding of the original injury. RaceTibial plateau fractures have no racial predilection. SexThe frequency of tibial plateau fractures is higher in older women than in older men, because of the greater incidence of osteoporosis in women. In younger patients, tibial plateau fractures typically affect men due to their greater involvement in high-energy contact sports such as wrestling and boxing. AgeFractures of the tibial plateau in older persons are more common than in the general population. Almost 8% of fractures occurring in older persons are estimated to involve the tibial plateau. This is a result of osteoporosis, with resultant depression-type fractures of the tibia becoming more common. AnatomyThe osseous structures of the knee include the tibia, fibula, patella, and femur. The principal bones involved in tibial plateau fractures are the femur and tibia. The tibia is composed of the medial and lateral tibial plateaus, as well as the intercondylar eminence. Each plateau articulates with its respective femoral condyle via the menisci, which are cartilaginous structures that are applied closely to each osseous surface. The anterior and posterior cruciate ligaments attach to the anterior and posterior aspects of the intercondylar tibia. The medial plateau generally is believed to be sturdier than the lateral plateau, supporting the clinical observation that medial plateau fractures typically result from the application of more severe forces than required to produce a fracture of the lateral plateau. Clinical DetailsPatients may present with a knee effusion, pain, and joint stiffness. Although severe fractures often are repaired surgically, both operatively and nonoperatively treated fractures are at risk for posttraumatic osteoarthritis as a result of ligamentous injuries with resultant instability (and possibly varus or valgus deformity). The risk of posttraumatic osteoarthritis is greatest in younger patients. Surgical intervention depends on numerous factors including the overall condition of the patient and associated local or regional injuries. From an orthopedic standpoint, the degree of articular depression and degree of diastasis of the fractured parts are the most crucial elements to be considered when making a decision regarding surgical intervention. As a general rule, 4-5 mm of articular depression and 3-4 mm of diastasis are considered indicators for surgical management. Preferred ExaminationThe preferred examination consists of radiographs in multiple obliquities of the knee. Typically, these include anteroposterior (AP), cross-table lateral, patellar (sunrise), and, possibly, oblique views. Cross-table lateral and AP may be the only views possible in the trauma suite. In this setting, the cross-table lateral radiograph may be the most important to detect occult fractures. The presence of these subtle fractures may be inferred by the presence of a lipohemarthrosis on the cross-table lateral radiograph, indicating disruption of an articular surface, most often the tibia. Images 3-6 demonstrate the radiographic, CT, and MRI appearance of lipohemarthrosis. CT is used by most orthopedists to further characterize fractures of the tibial plateau and assess the depression of the tibia and the degree of diastasis (splitting) of the fractured parts to plan for surgical intervention. Generally, slice thickness should be minimized (1 mm is ideal) and high milliamperage-second (mAs) technique used. MRI may be used as well for this determination but often is not readily available. MRI is excellent for depicting ligamentous and meniscal injuries. Arteriography (and possibly MR angiography) may be used if popliteal artery injury is suspected. Limitations of TechniquesNondepressed tibial plateau fractures occasionally are difficult to appreciate with standard radiographs. Cross-table lateral radiographs may demonstrate a lipohemarthrosis within the joint, with layering of bone marrow fat upon blood (see Image 3). If lipohemarthrosis is present, an intra-articular fracture is present and must be located. In this situation, axial CT is an excellent tool for defining fracture anatomy using reconstructed images in the sagittal and coronal planes. RADIOGRAPHSection 3 of 11
FindingsMany methods have been developed to classify tibial plateau fractures. The following Schatzker system is the best known (see Images 1-2):
Degree of ConfidenceMost fractures of the tibial plateau are diagnosed readily by conventional radiography. CT often is used to confirm the anatomic relationship of fracture fragments with more complex fractures, especially at the articular surface of the tibia where precise 3-dimensional anatomy is critical to the success of surgical repair. Less comminuted and depressed fractures may not require imaging by CT. False Positives/NegativesA false-negative radiograph may be encountered on the rare occasions in which a fracture is present but only a lipohemarthrosis is visualized. In these patients, CT or MRI is required to visualize the fracture. CT SCANSection 4 of 11
FindingsIn most patients, CT mimics the findings of conventional radiography. With reconstruction of the axial images into both coronal and sagittal planes, precise localization of surgical landmarks, as well all fracture fragments, is obtained. CT is critical in formulating a surgical plan for Schatzker type IV, V, and VI fractures. Degree of ConfidenceCT data usually is unequivocal for osseous injury. For full depiction of soft tissue injury, such as ligaments and menisci, MRI is superior. False Positives/NegativesCT generally is able to depict all fractures. False-negative errors can occur when only axial imaging is used. If a fracture predominates in the axial plane, it may be overlooked by CT. However, in most instances, sagittal and coronal reconstructions of axial data are used to avoid this problem (see Image 13, Image 17). By reconstructing the initial data set into different planes, additional information such as articular depression and diastasis may be obtained easily. False positives are not common with CT. MRISection 5 of 11
FindingsThe role of MRI in the acute management of tibial plateau fractures is under investigation. A recent study by Kode et al (1994) investigated the usefulness of CT and MRI in visualizing fracture patterns. MRI was superior to CT unless the fracture was extremely comminuted. Meniscal injuries, as well as injuries to the collateral and cruciate ligaments, are depicted better with MRI than with CT. The value of CT is in the speed and availability of the technique. In addition, most patients with extensive injuries also undergo CT of other portions of the body in the trauma setting. With current scanners, image thickness of 1 mm or less is possible, which generally yields unequivocal depiction of fracture patterns. Degree of ConfidenceMRI is very sensitive to the presence of osseous injury. Injuries to osseous structures manifest as areas of edema within bone marrow. However, fractures through the cortex are less well depicted, as cortical bone appears as an area of low signal (generally black) on MRI sequences. Thus, fractures through cortical bone can be difficult to depict with MRI. Complex and comminuted fractures with multiple cortical fragments are exceedingly difficult to analyze with MRI. False Positives/NegativesFalse negatives with MRI are uncommon. MRI is used routinely for the detection of occult fracture because of its superior depiction of bone marrow edema, a direct indicator of osseous injury. False-negative information may result when MRI data is analyzed for the presence of cortical fractures. Both false-negative and false-positive errors may occur if the incorrect MRI sequences are chosen. In general, a fluid sensitive sequence such as short tau inversion recovery is best to detect bone marrow edema rather than a simple T2-weighted sequence. ULTRASOUNDSection 6 of 11
FindingsUltrasound is not used in the diagnosis of tibial plateau fractures. NUCLEAR MEDICINESection 7 of 11
FindingsNuclear medicine studies are not used in the diagnosis of tibial plateau fractures, unless a stress-type fracture is suspected or concern for osteomyelitis exists. ANGIOGRAPHYSection 8 of 11
FindingsType IV fractures involving the medial tibial plateau raise concern for injury to the popliteal artery. These arterial injuries can be clinically silent or present with decreased peripheral pulses. If clinical concern exists for a popliteal artery injury with any fracture type, obtain an arteriogram (or possibly MR angiography). Surgical manipulation of the tissues surrounding an injured popliteal artery can result in thrombosis, with dire consequences unless the thrombosis is addressed immediately. However, angiography is not used for the primary detection of tibial plateau fractures. INTERVENTIONSection 9 of 11
Management of tibial plateau fractures is generally nonradiologic. Radiologic intervention may be needed when thrombosis of the popliteal artery is seen and an attempt is made to lyse the clot with percutaneous techniques; however, this is rare. Medical/Legal Pitfalls
See also the Medscape topic Medical Malpractice and Legal Issues. MULTIMEDIASection 10 of 11
REFERENCESSection 11 of 11
Tibial Plateau Fractures excerpt Article Last Updated: Jan 24, 2007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
